The AEGIS Family of Authenticated Encryption Algorithms
draft-irtf-cfrg-aegis-aead-10
| Document | Type | Active Internet-Draft (cfrg RG) | |
|---|---|---|---|
| Authors | Frank Denis , Samuel Lucas | ||
| Last updated | 2024-01-20 | ||
| Replaces | draft-denis-aegis-aead | ||
| RFC stream | Internet Research Task Force (IRTF) | ||
| Intended RFC status | Informational | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| Stream | IRTF state | Active RG Document | |
| Consensus boilerplate | Unknown | ||
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draft-irtf-cfrg-aegis-aead-10
Crypto Forum F. Denis
Internet-Draft Fastly Inc.
Intended status: Informational S. Lucas
Expires: 23 July 2024 Individual Contributor
20 January 2024
The AEGIS Family of Authenticated Encryption Algorithms
draft-irtf-cfrg-aegis-aead-10
Abstract
This document describes the AEGIS-128L, AEGIS-256, AEGIS-128X, and
AEGIS-256X AES-based authenticated encryption algorithms designed for
high-performance applications.
The document is a product of the Crypto Forum Research Group (CFRG).
It is not an IETF product and is not a standard.
Discussion Venues
This note is to be removed before publishing as an RFC.
Source for this draft and an issue tracker can be found at
https://github.com/cfrg/draft-irtf-cfrg-aegis-aead.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 23 July 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 5
3. The AEGIS-128L Algorithm . . . . . . . . . . . . . . . . . . 8
3.1. Authenticated Encryption . . . . . . . . . . . . . . . . 8
3.2. Authenticated Decryption . . . . . . . . . . . . . . . . 9
3.3. The Init Function . . . . . . . . . . . . . . . . . . . . 10
3.4. The Update Function . . . . . . . . . . . . . . . . . . . 11
3.5. The Absorb Function . . . . . . . . . . . . . . . . . . . 12
3.6. The Enc Function . . . . . . . . . . . . . . . . . . . . 12
3.7. The Dec Function . . . . . . . . . . . . . . . . . . . . 13
3.8. The DecPartial Function . . . . . . . . . . . . . . . . . 13
3.9. The Finalize Function . . . . . . . . . . . . . . . . . . 14
4. The AEGIS-256 Algorithm . . . . . . . . . . . . . . . . . . . 15
4.1. Authenticated Encryption . . . . . . . . . . . . . . . . 15
4.2. Authenticated Decryption . . . . . . . . . . . . . . . . 16
4.3. The Init Function . . . . . . . . . . . . . . . . . . . . 18
4.4. The Update Function . . . . . . . . . . . . . . . . . . . 19
4.5. The Absorb Function . . . . . . . . . . . . . . . . . . . 20
4.6. The Enc Function . . . . . . . . . . . . . . . . . . . . 20
4.7. The Dec Function . . . . . . . . . . . . . . . . . . . . 20
4.8. The DecPartial Function . . . . . . . . . . . . . . . . . 21
4.9. The Finalize Function . . . . . . . . . . . . . . . . . . 22
5. Parallel Modes . . . . . . . . . . . . . . . . . . . . . . . 22
5.1. Additional Conventions and Definitions . . . . . . . . . 23
5.2. Authenticated Encryption . . . . . . . . . . . . . . . . 23
5.3. Authenticated Decryption . . . . . . . . . . . . . . . . 24
5.4. AEGIS-128X . . . . . . . . . . . . . . . . . . . . . . . 25
5.4.1. The Init Function . . . . . . . . . . . . . . . . . . 25
5.4.2. The Update Function . . . . . . . . . . . . . . . . . 26
5.4.3. The Absorb Function . . . . . . . . . . . . . . . . . 27
5.4.4. The Enc Function . . . . . . . . . . . . . . . . . . 27
5.4.5. The Dec Function . . . . . . . . . . . . . . . . . . 28
5.4.6. The DecPartial Function . . . . . . . . . . . . . . . 28
5.4.7. The Finalize Function . . . . . . . . . . . . . . . . 29
5.5. AEGIS-256X . . . . . . . . . . . . . . . . . . . . . . . 30
5.5.1. The Init Function . . . . . . . . . . . . . . . . . . 30
5.5.2. The Update Function . . . . . . . . . . . . . . . . . 31
5.5.3. The Absorb Function . . . . . . . . . . . . . . . . . 31
5.5.4. The Enc Function . . . . . . . . . . . . . . . . . . 31
5.5.5. The Dec Function . . . . . . . . . . . . . . . . . . 32
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5.5.6. The DecPartial Function . . . . . . . . . . . . . . . 32
5.5.7. The Finalize Function . . . . . . . . . . . . . . . . 33
5.6. Implementation Considerations . . . . . . . . . . . . . . 34
5.7. Operational Considerations . . . . . . . . . . . . . . . 34
6. Encoding (ct, tag) Tuples . . . . . . . . . . . . . . . . . . 35
7. AEGIS as a Stream Cipher . . . . . . . . . . . . . . . . . . 35
8. Implementation Status . . . . . . . . . . . . . . . . . . . . 36
9. Security Considerations . . . . . . . . . . . . . . . . . . . 36
9.1. Usage Guidelines . . . . . . . . . . . . . . . . . . . . 36
9.1.1. Key and Nonce Selection . . . . . . . . . . . . . . . 36
9.1.2. Key Commitment . . . . . . . . . . . . . . . . . . . 36
9.1.3. Multi-User Security . . . . . . . . . . . . . . . . . 37
9.1.4. Other Uses of AEGIS . . . . . . . . . . . . . . . . . 37
9.2. Implementation Security . . . . . . . . . . . . . . . . . 37
9.3. Security Guarantees . . . . . . . . . . . . . . . . . . . 38
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 38
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 39
11.1. Normative References . . . . . . . . . . . . . . . . . . 39
11.2. Informative References . . . . . . . . . . . . . . . . . 40
Appendix A. Test Vectors . . . . . . . . . . . . . . . . . . . . 41
A.1. AESRound Test Vector . . . . . . . . . . . . . . . . . . 41
A.2. AEGIS-128L Test Vectors . . . . . . . . . . . . . . . . . 41
A.2.1. Update Test Vector . . . . . . . . . . . . . . . . . 41
A.2.2. Test Vector 1 . . . . . . . . . . . . . . . . . . . . 42
A.2.3. Test Vector 2 . . . . . . . . . . . . . . . . . . . . 42
A.2.4. Test Vector 3 . . . . . . . . . . . . . . . . . . . . 43
A.2.5. Test Vector 4 . . . . . . . . . . . . . . . . . . . . 43
A.2.6. Test Vector 5 . . . . . . . . . . . . . . . . . . . . 44
A.2.7. Test Vector 6 . . . . . . . . . . . . . . . . . . . . 44
A.2.8. Test Vector 7 . . . . . . . . . . . . . . . . . . . . 45
A.2.9. Test Vector 8 . . . . . . . . . . . . . . . . . . . . 45
A.2.10. Test Vector 9 . . . . . . . . . . . . . . . . . . . . 46
A.3. AEGIS-256 Test Vectors . . . . . . . . . . . . . . . . . 46
A.3.1. Update Test Vector . . . . . . . . . . . . . . . . . 46
A.3.2. Test Vector 1 . . . . . . . . . . . . . . . . . . . . 46
A.3.3. Test Vector 2 . . . . . . . . . . . . . . . . . . . . 47
A.3.4. Test Vector 3 . . . . . . . . . . . . . . . . . . . . 47
A.3.5. Test Vector 4 . . . . . . . . . . . . . . . . . . . . 48
A.3.6. Test Vector 5 . . . . . . . . . . . . . . . . . . . . 48
A.3.7. Test Vector 6 . . . . . . . . . . . . . . . . . . . . 49
A.3.8. Test Vector 7 . . . . . . . . . . . . . . . . . . . . 49
A.3.9. Test Vector 8 . . . . . . . . . . . . . . . . . . . . 50
A.3.10. Test Vector 9 . . . . . . . . . . . . . . . . . . . . 50
A.4. AEGIS-128X2 Test Vectors . . . . . . . . . . . . . . . . 51
A.4.1. Initial State . . . . . . . . . . . . . . . . . . . . 51
A.4.2. Test Vector 1 . . . . . . . . . . . . . . . . . . . . 52
A.4.3. Test Vector 2 . . . . . . . . . . . . . . . . . . . . 52
A.5. AEGIS-128X4 Test Vectors . . . . . . . . . . . . . . . . 53
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A.5.1. Initial State . . . . . . . . . . . . . . . . . . . . 53
A.5.2. Test Vector 1 . . . . . . . . . . . . . . . . . . . . 54
A.5.3. Test Vector 2 . . . . . . . . . . . . . . . . . . . . 55
A.6. AEGIS-256X2 Test Vectors . . . . . . . . . . . . . . . . 55
A.6.1. Initial State . . . . . . . . . . . . . . . . . . . . 56
A.6.2. Test Vector 1 . . . . . . . . . . . . . . . . . . . . 56
A.6.3. Test Vector 2 . . . . . . . . . . . . . . . . . . . . 57
A.7. AEGIS-256X4 Test Vectors . . . . . . . . . . . . . . . . 58
A.7.1. Initial State . . . . . . . . . . . . . . . . . . . . 58
A.7.2. Test Vector 1 . . . . . . . . . . . . . . . . . . . . 59
A.7.3. Test Vector 2 . . . . . . . . . . . . . . . . . . . . 60
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 60
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 61
1. Introduction
This document describes the AEGIS family of authenticated encryption
with associated data (AEAD) algorithms [AEGIS], which were chosen as
additional finalists for high-performance applications in the
Competition for Authenticated Encryption: Security, Applicability,
and Robustness (CAESAR). Whilst AEGIS-128 was selected as a winner
for this use case, AEGIS-128L has a better security margin alongside
improved performance and AEGIS-256 uses a 256-bit key [LIMS21]. All
variants of AEGIS are inverse-free and constructed from the AES
encryption round function [FIPS-AES]. This document specifies:
* AEGIS-128L, which has a 128-bit key, a 128-bit nonce, a 1024-bit
state, a 128- or 256-bit authentication tag, and processes 256-bit
input blocks.
* AEGIS-256, which has a 256-bit key, a 256-bit nonce, a 768-bit
state, a 128- or 256-bit authentication tag, and processes 128-bit
input blocks.
* AEGIS-128X, which is a mode based on AEGIS-128L, specialized for
CPUs with large vector registers and vector AES instructions.
* AEGIS-256X, which is a mode based on AEGIS-256, specialized for
CPUs with large vector registers and vector AES instructions.
The AEGIS cipher family offers performance that significantly exceeds
that of AES-GCM with hardware support for parallelizable AES block
encryption [AEGIS]. Similarly, software implementations can also be
faster, although to a lesser extent.
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Unlike with AES-GCM, nonces can be safely chosen at random with no
practical limit when using AEGIS-256 and AEGIS-256X. AEGIS-128L and
AEGIS-128X also allow for more messages to be safely encrypted when
using random nonces.
With some existing AEAD schemes, such as AES-GCM, an attacker can
generate a ciphertext that successfully decrypts under multiple
different keys (a partitioning oracle attack) [LGR21]. This ability
to craft a (ciphertext, authentication tag) pair that verifies under
multiple keys significantly reduces the number of required
interactions with the oracle in order to perform an exhaustive
search, making it practical if the key space is small. For example,
with password-based encryption, an attacker can guess a large number
of passwords at a time by recursively submitting such a ciphertext to
an oracle, which speeds up a password search by reducing it to a
binary search.
In AEGIS, finding distinct (key, nonce) pairs that successfully
decrypt a given (associated data, ciphertext, authentication tag)
tuple is believed to have a complexity that depends on the tag size.
A 128-bit tag provides 64-bit committing security, which is generally
acceptable for interactive protocols. With a 256-bit tag, finding a
collision becomes impractical.
Unlike most other AES-based AEAD constructions, leaking a state does
not leak the key nor previous states.
Finally, an AEGIS key is not required after the setup phase, and
there is no key schedule. Thus, ephemeral keys can be erased from
memory before any data has been encrypted or decrypted, mitigating
cold boot attacks.
Note that an earlier version of Hongjun Wu and Bart Preneel’s paper
introducing AEGIS specified AEGIS-128L and AEGIS-256 sporting
differences with regards to the computation of the authentication tag
and the number of rounds in the Finalize() function. We follow the
specification of [AEGIS], which can be found in the References
section of this document.
2. Conventions and Definitions
The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”,
“SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “NOT RECOMMENDED”, “MAY”, and
“OPTIONAL” in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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Throughout this document, “byte” is used interchangeably with “octet”
and refers to an 8-bit sequence.
Primitives:
* {}: an empty bit array.
* |x|: the length of x in bits.
* a ^ b: the bitwise exclusive OR operation between a and b.
* a & b: the bitwise AND operation between a and b.
* a || b: the concatenation of a and b.
* a mod b: the remainder of the Euclidean division between a as the
dividend and b as the divisor.
* LE64(x): the little-endian encoding of unsigned 64-bit integer x.
* ZeroPad(x, n): padding operation. Trailing zeros are concatenated
to x until the total length is a multiple of n bits.
* Truncate(x, n): truncation operation. The first n bits of x are
kept.
* Split(x, n): splitting operation. x is split into n-bit blocks,
ignoring partial blocks.
* Tail(x, n): returns the last n bits of x.
* AESRound(in, rk): a single round of the AES encryption round
function, which is the composition of the SubBytes, ShiftRows,
MixColums and AddRoundKey transformations, as defined in section 5
of [FIPS-AES]. Here, in is the 128-bit AES input state, and rk is
the 128-bit round key.
* Repeat(n, F): n sequential evaluations of the function F.
* CtEq(a, b): compares a and b in constant-time, returning True for
an exact match, False otherwise.
AEGIS internal functions:
* Update(M0, M1) or Update(M): the state update function.
* Init(key, nonce): the initialization function.
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* Absorb(ai): the input block absorption function.
* Enc(xi): the input block encryption function.
* Dec(ci): the input block decryption function.
* DecPartial(cn): the input block decryption function for the last
ciphertext bits when they do not fill an entire block.
* Finalize(ad_len_bits, msg_len_bits): the authentication tag
generation function.
Input blocks are 256 bits for AEGIS-128L and 128 bits for AEGIS-256.
AES blocks:
* Si: the i-th AES block of the current state.
* S'i: the i-th AES block of the next state.
* {Si, ...Sj}: the vector of the i-th AES block of the current state
to the j-th block of the current state.
* C0: an AES block built from the following bytes in hexadecimal
format: { 0x00, 0x01, 0x01, 0x02, 0x03, 0x05, 0x08, 0x0d, 0x15,
0x22, 0x37, 0x59, 0x90, 0xe9, 0x79, 0x62 }.
* C1: an AES block built from the following bytes in hexadecimal
format: { 0xdb, 0x3d, 0x18, 0x55, 0x6d, 0xc2, 0x2f, 0xf1, 0x20,
0x11, 0x31, 0x42, 0x73, 0xb5, 0x28, 0xdd }.
AES blocks are always 128 bits in length.
Input and output values:
* key: the encryption key (128 bits for AEGIS-128L, 256 bits for
AEGIS-256).
* nonce: the public nonce (128 bits for AEGIS-128L, 256 bits for
AEGIS-256).
* ad: the associated data.
* msg: the plaintext.
* ct: the ciphertext.
* tag: the authentication tag (128 or 256 bits).
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3. The AEGIS-128L Algorithm
AEGIS-128L has a 1024-bit state, made of eight 128-bit blocks {S0,
...S7}.
The parameters for this algorithm, whose meaning is defined in
[RFC5116], Section 4 are:
* K_LEN (key length) is 16 bytes (128 bits).
* P_MAX (maximum length of the plaintext) is 2^61 bytes (2^64 bits).
* A_MAX (maximum length of the associated data) is 2^61 bytes (2^64
bits).
* N_MIN (minimum nonce length) = N_MAX (maximum nonce length) = 16
bytes (128 bits).
* C_MAX (maximum ciphertext length) = P_MAX + tag length = 2^61 + 16
or 32 bytes (2^64 + 128 or 256 bits).
Distinct associated data inputs, as described in [RFC5116], Section 3
shall be unambiguously encoded as a single input. It is up to the
application to create a structure in the associated data input if
needed.
3.1. Authenticated Encryption
Encrypt(msg, ad, key, nonce)
The Encrypt function encrypts a message and returns the ciphertext
along with an authentication tag that verifies the authenticity of
the message and associated data, if provided.
Security:
* For a given key, the nonce MUST NOT be reused under any
circumstances; doing so allows an attacker to recover the internal
state.
* The key MUST be randomly chosen from a uniform distribution.
Inputs:
* msg: the message to be encrypted (length MUST be less than P_MAX).
* ad: the associated data to authenticate (length MUST be less than
A_MAX).
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* key: the encryption key.
* nonce: the public nonce.
Outputs:
* ct: the ciphertext.
* tag: the authentication tag.
Steps:
Init(key, nonce)
ct = {}
ad_blocks = Split(ZeroPad(ad, 256), 256)
for ai in ad_blocks:
Absorb(ai)
msg_blocks = Split(ZeroPad(msg, 256), 256)
for xi in msg_blocks:
ct = ct || Enc(xi)
tag = Finalize(|ad|, |msg|)
ct = Truncate(ct, |msg|)
return ct and tag
3.2. Authenticated Decryption
Decrypt(ct, tag, ad, key, nonce)
The Decrypt function decrypts a ciphertext, verifies that the
authentication tag is correct, and returns the message on success or
an error if tag verification failed.
Security:
* If tag verification fails, the decrypted message and wrong message
authentication tag MUST NOT be given as output. The decrypted
message MUST be overwritten with zeros.
* The comparison of the input tag with the expected_tag MUST be done
in constant time.
Inputs:
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* ct: the ciphertext to be decrypted (length MUST be less than
C_MAX).
* tag: the authentication tag.
* ad: the associated data to authenticate (length MUST be less than
A_MAX).
* key: the encryption key.
* nonce: the public nonce.
Outputs:
* Either the decrypted message msg or an error indicating that the
authentication tag is invalid for the given inputs.
Steps:
Init(key, nonce)
msg = {}
ad_blocks = Split(ZeroPad(ad, 256), 256)
for ai in ad_blocks:
Absorb(ai)
ct_blocks = Split(ct, 256)
cn = Tail(ct, |ct| mod 256)
for ci in ct_blocks:
msg = msg || Dec(ci)
if cn is not empty:
msg = msg || DecPartial(cn)
expected_tag = Finalize(|ad|, |msg|)
if CtEq(tag, expected_tag) is False:
erase msg
return "verification failed" error
else:
return msg
3.3. The Init Function
Init(key, nonce)
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The Init function constructs the initial state {S0, ...S7} using the
given key and nonce.
Inputs:
* key: the encryption key.
* nonce: the public nonce.
Defines:
* {S0, ...S7}: the initial state.
Steps:
S0 = key ^ nonce
S1 = C1
S2 = C0
S3 = C1
S4 = key ^ nonce
S5 = key ^ C0
S6 = key ^ C1
S7 = key ^ C0
Repeat(10, Update(nonce, key))
3.4. The Update Function
Update(M0, M1)
The Update function is the core of the AEGIS-128L algorithm. It
updates the state {S0, ...S7} using two 128-bit values.
Inputs:
* M0: the first 128-bit block to be absorbed.
* M1: the second 128-bit block to be absorbed.
Modifies:
* {S0, ...S7}: the state.
Steps:
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S'0 = AESRound(S7, S0 ^ M0)
S'1 = AESRound(S0, S1)
S'2 = AESRound(S1, S2)
S'3 = AESRound(S2, S3)
S'4 = AESRound(S3, S4 ^ M1)
S'5 = AESRound(S4, S5)
S'6 = AESRound(S5, S6)
S'7 = AESRound(S6, S7)
S0 = S'0
S1 = S'1
S2 = S'2
S3 = S'3
S4 = S'4
S5 = S'5
S6 = S'6
S7 = S'7
3.5. The Absorb Function
Absorb(ai)
The Absorb function absorbs a 256-bit input block ai into the state
{S0, ...S7}.
Inputs:
* ai: the 256-bit input block.
Steps:
t0, t1 = Split(ai, 128)
Update(t0, t1)
3.6. The Enc Function
Enc(xi)
The Enc function encrypts a 256-bit input block xi using the state
{S0, ...S7}.
Inputs:
* xi: the 256-bit input block.
Outputs:
* ci: the 256-bit encrypted block.
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Steps:
z0 = S6 ^ S1 ^ (S2 & S3)
z1 = S2 ^ S5 ^ (S6 & S7)
t0, t1 = Split(xi, 128)
out0 = t0 ^ z0
out1 = t1 ^ z1
Update(t0, t1)
ci = out0 || out1
return ci
3.7. The Dec Function
Dec(ci)
The Dec function decrypts a 256-bit input block ci using the state
{S0, ...S7}.
Inputs:
* ci: the 256-bit encrypted block.
Outputs:
* xi: the 256-bit decrypted block.
Steps:
z0 = S6 ^ S1 ^ (S2 & S3)
z1 = S2 ^ S5 ^ (S6 & S7)
t0, t1 = Split(ci, 128)
out0 = t0 ^ z0
out1 = t1 ^ z1
Update(out0, out1)
xi = out0 || out1
return xi
3.8. The DecPartial Function
DecPartial(cn)
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The DecPartial function decrypts the last ciphertext bits cn using
the state {S0, ...S7} when they do not fill an entire block.
Inputs:
* cn: the encrypted input.
Outputs:
* xn: the decryption of cn.
Steps:
z0 = S6 ^ S1 ^ (S2 & S3)
z1 = S2 ^ S5 ^ (S6 & S7)
t0, t1 = Split(ZeroPad(cn, 256), 128)
out0 = t0 ^ z0
out1 = t1 ^ z1
xn = Truncate(out0 || out1, |cn|)
v0, v1 = Split(ZeroPad(xn, 256), 128)
Update(v0, v1)
return xn
3.9. The Finalize Function
Finalize(ad_len_bits, msg_len_bits)
The Finalize function computes a 128- or 256-bit tag that
authenticates the message and associated data.
Inputs:
* ad_len_bits: the length of the associated data in bits.
* msg_len_bits: the length of the message in bits.
Outputs:
* tag: the authentication tag.
Steps:
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t = S2 ^ (LE64(ad_len_bits) || LE64(msg_len_bits))
Repeat(7, Update(t, t))
if tag_length == 16: # 128 bits
tag = S0 ^ S1 ^ S2 ^ S3 ^ S4 ^ S5 ^ S6
else: # 256 bits
tag = (S0 ^ S1 ^ S2 ^ S3) || (S4 ^ S5 ^ S6 ^ S7)
return tag
4. The AEGIS-256 Algorithm
AEGIS-256 has a 768-bit state, made of six 128-bit blocks {S0,
...S5}.
The parameters for this algorithm, whose meaning is defined in
[RFC5116], Section 4 are:
* K_LEN (key length) is 32 bytes (256 bits).
* P_MAX (maximum length of the plaintext) is 2^61 bytes (2^64 bits).
* A_MAX (maximum length of the associated data) is 2^61 bytes (2^64
bits).
* N_MIN (minimum nonce length) = N_MAX (maximum nonce length) = 32
bytes (256 bits).
* C_MAX (maximum ciphertext length) = P_MAX + tag length = 2^61 + 16
or 32 bytes (2^64 + 128 or 256 bits).
Distinct associated data inputs, as described in [RFC5116], Section 3
shall be unambiguously encoded as a single input. It is up to the
application to create a structure in the associated data input if
needed.
4.1. Authenticated Encryption
Encrypt(msg, ad, key, nonce)
The Encrypt function encrypts a message and returns the ciphertext
along with an authentication tag that verifies the authenticity of
the message and associated data, if provided.
Security:
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* For a given key, the nonce MUST NOT be reused under any
circumstances; doing so allows an attacker to recover the internal
state.
* The key MUST be randomly chosen from a uniform distribution.
Inputs:
* msg: the message to be encrypted (length MUST be less than P_MAX).
* ad: the associated data to authenticate (length MUST be less than
A_MAX).
* key: the encryption key.
* nonce: the public nonce.
Outputs:
* ct: the ciphertext.
* tag: the authentication tag.
Steps:
Init(key, nonce)
ct = {}
ad_blocks = Split(ZeroPad(ad, 128), 128)
for ai in ad_blocks:
Absorb(ai)
msg_blocks = Split(ZeroPad(msg, 128), 128)
for xi in msg_blocks:
ct = ct || Enc(xi)
tag = Finalize(|ad|, |msg|)
ct = Truncate(ct, |msg|)
return ct and tag
4.2. Authenticated Decryption
Decrypt(ct, tag, ad, key, nonce)
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The Decrypt function decrypts a ciphertext, verifies that the
authentication tag is correct, and returns the message on success or
an error if tag verification failed.
Security:
* If tag verification fails, the decrypted message and wrong message
authentication tag MUST NOT be given as output. The decrypted
message MUST be overwritten with zeros.
* The comparison of the input tag with the expected_tag MUST be done
in constant time.
Inputs:
* ct: the ciphertext to be decrypted (length MUST be less than
C_MAX).
* tag: the authentication tag.
* ad: the associated data to authenticate (length MUST be less than
A_MAX).
* key: the encryption key.
* nonce: the public nonce.
Outputs:
* Either the decrypted message msg or an error indicating that the
authentication tag is invalid for the given inputs.
Steps:
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Init(key, nonce)
msg = {}
ad_blocks = Split(ZeroPad(ad, 128), 128)
for ai in ad_blocks:
Absorb(ai)
ct_blocks = Split(ZeroPad(ct, 128), 128)
cn = Tail(ct, |ct| mod 128)
for ci in ct_blocks:
msg = msg || Dec(ci)
if cn is not empty:
msg = msg || DecPartial(cn)
expected_tag = Finalize(|ad|, |msg|)
if CtEq(tag, expected_tag) is False:
erase msg
return "verification failed" error
else:
return msg
4.3. The Init Function
Init(key, nonce)
The Init function constructs the initial state {S0, ...S5} using the
given key and nonce.
Inputs:
* key: the encryption key.
* nonce: the public nonce.
Defines:
* {S0, ...S5}: the initial state.
Steps:
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k0, k1 = Split(key, 128)
n0, n1 = Split(nonce, 128)
S0 = k0 ^ n0
S1 = k1 ^ n1
S2 = C1
S3 = C0
S4 = k0 ^ C0
S5 = k1 ^ C1
Repeat(4,
Update(k0)
Update(k1)
Update(k0 ^ n0)
Update(k1 ^ n1)
)
4.4. The Update Function
Update(M)
The Update function is the core of the AEGIS-256 algorithm. It
updates the state {S0, ...S5} using a 128-bit value.
Inputs:
* msg: the block to be absorbed.
Modifies:
* {S0, ...S5}: the state.
Steps:
S'0 = AESRound(S5, S0 ^ M)
S'1 = AESRound(S0, S1)
S'2 = AESRound(S1, S2)
S'3 = AESRound(S2, S3)
S'4 = AESRound(S3, S4)
S'5 = AESRound(S4, S5)
S0 = S'0
S1 = S'1
S2 = S'2
S3 = S'3
S4 = S'4
S5 = S'5
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4.5. The Absorb Function
Absorb(ai)
The Absorb function absorbs a 128-bit input block ai into the state
{S0, ...S5}.
Inputs:
* ai: the input block.
Steps:
Update(ai)
4.6. The Enc Function
Enc(xi)
The Enc function encrypts a 128-bit input block xi using the state
{S0, ...S5}.
Inputs:
* xi: the input block.
Outputs:
* ci: the encrypted input block.
Steps:
z = S1 ^ S4 ^ S5 ^ (S2 & S3)
Update(xi)
ci = xi ^ z
return ci
4.7. The Dec Function
Dec(ci)
The Dec function decrypts a 128-bit input block ci using the state
{S0, ...S5}.
Inputs:
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* ci: the encrypted input block.
Outputs:
* xi: the decrypted block.
Steps:
z = S1 ^ S4 ^ S5 ^ (S2 & S3)
xi = ci ^ z
Update(xi)
return xi
4.8. The DecPartial Function
DecPartial(cn)
The DecPartial function decrypts the last ciphertext bits cn using
the state {S0, ...S5} when they do not fill an entire block.
Inputs:
* cn: the encrypted input.
Outputs:
* xn: the decryption of cn.
Steps:
z = S1 ^ S4 ^ S5 ^ (S2 & S3)
t = ZeroPad(cn, 128)
out = t ^ z
xn = Truncate(out, |cn|)
v = ZeroPad(xn, 128)
Update(v)
return xn
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4.9. The Finalize Function
Finalize(ad_len_bits, msg_len_bits)
The Finalize function computes a 128- or 256-bit tag that
authenticates the message and associated data.
Inputs:
* ad_len_bits: the length of the associated data in bits.
* msg_len_bits: the length of the message in bits.
Outputs:
* tag: the authentication tag.
Steps:
t = S3 ^ (LE64(ad_len_bits) || LE64(msg_len_bits))
Repeat(7, Update(t))
if tag_length == 16: # 128 bits
tag = S0 ^ S1 ^ S2 ^ S3 ^ S4 ^ S5
else: # 256 bits
tag = (S0 ^ S1 ^ S2) || (S3 ^ S4 ^ S5)
return tag
5. Parallel Modes
Some CPUs, such as Intel and Intel-compatible CPUs with the VAES
extensions, include instructions to efficiently apply the AES round
function to a vector of AES blocks.
AEGIS-128X and AEGIS-256X are optional, specialized modes designed to
take advantage of these instructions. They share the same properties
as the ciphers they are based on but can be significantly faster on
these platforms, even for short messages.
AEGIS-128X and AEGIS-256X are parallel evaluations of multiple AEGIS-
128L and AEGIS-256 instances respectively, with distinct initial
states. On CPUs with wide vector registers, different states can be
stored in different 128-bit lanes of the same vector register,
allowing parallel updates using vector instructions.
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The modes are parameterized by the parallelism degree. With 256-bit
registers, 2 parallel operations can be applied to 128-bit AES
blocks. With 512-bit registers, the number of instances can be
raised to 4.
The state of a parallel mode is represented as a vector of AEGIS-128L
or AEGIS-256 states.
5.1. Additional Conventions and Definitions
* D: the degree of parallelism.
* R: the absorption and output rate of the mode. With AEGIS-128X,
the rate is 2 * 128 * D bits. With AEGIS-256X, the rate is 128 *
D bits.
* V[j,i]: the j-th AES block of the i-th state. i is in the [0..D)
range. For AEGIS-128X, j is in the [0..8) range, while for AEGIS-
256, j is in the [0..6) range.
* V'[j,i]: the j-th AES block of the next i-th state.
* ctx[i]: the i-th context separator. This is a 128-bit mask, made
of a byte representing the state index, followed by a byte
representing the highest index and 112 all-zero bits.
* Byte(x): the value x encoded as 8 bits.
5.2. Authenticated Encryption
Encrypt(msg, ad, key, nonce)
The Encrypt function of AEGIS-128X resembles that of AEGIS-128L, and
similarly, the Encrypt function of AEGIS-256X mirrors that of AEGIS-
256, but processes R-bit input blocks per update.
Steps:
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Init(key, nonce)
ct = {}
ad_blocks = Split(ZeroPad(ad, R), R)
for ai in ad_blocks:
Absorb(ai)
msg_blocks = Split(ZeroPad(msg, R), R)
for xi in msg_blocks:
ct = ct || Enc(xi)
tag = Finalize(|ad|, |msg|)
ct = Truncate(ct, |msg|)
return ct and tag
5.3. Authenticated Decryption
Decrypt(ct, tag, ad, key, nonce)
The Decrypt function of AEGIS-128X resembles that of AEGIS-128L, and
similarly, the Decrypt function of AEGIS-256X mirrors that of AEGIS-
256, but processes R-bit input blocks per update.
Steps:
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Init(key, nonce)
msg = {}
ad_blocks = Split(ZeroPad(ad, R), R)
for ai in ad_blocks:
Absorb(ai)
ct_blocks = Split(ct, R)
cn = Tail(ct, |ct| mod R)
for ci in ct_blocks:
msg = msg || Dec(ci)
if cn is not empty:
msg = msg || DecPartial(cn)
expected_tag = Finalize(|ad|, |msg|)
if CtEq(tag, expected_tag) is False:
erase msg
return "verification failed" error
else:
return msg
5.4. AEGIS-128X
5.4.1. The Init Function
Init(key, nonce)
The Init function initializes a vector of D AEGIS-128L states with
the same key and nonce but a different context ctx[i]. The context
is added to the state before every update.
Steps:
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for i in 0..D:
V[0,i] = key ^ nonce
V[1,i] = C1
V[2,i] = C0
V[3,i] = C1
V[4,i] = key ^ nonce
V[5,i] = key ^ C0
V[6,i] = key ^ C1
V[7,i] = key ^ C0
nonce_v = {}
key_v = {}
for i in 0..D:
nonce_v = nonce_v || nonce
key_v = key_v || key
Repeat(10,
for i in 0..D:
ctx[i] = ZeroPad(Byte(i) || Byte(D - 1), 128)
V[3,i] = V[3,i] ^ ctx[i]
V[7,i] = V[7,i] ^ ctx[i]
Update(nonce_v, key_v)
)
5.4.2. The Update Function
Update(M0, M1)
The AEGIS-128X Update function is similar to the AEGIS-128L Update
function, but absorbs R (2 * 128 * D) bits at once. M0 and M1 are
128 * D bits instead of 128 bits but are split into 128-bit blocks,
each of them updating a different AEGIS-128L state.
Steps:
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m0 = Split(M0, 128)
m1 = Split(M1, 128)
for i in 0..D:
V'[0,i] = AESRound(V[7,i], V[0,i] ^ m0[i])
V'[1,i] = AESRound(V[0,i], V[1,i])
V'[2,i] = AESRound(V[1,i], V[2,i])
V'[3,i] = AESRound(V[2,i], V[3,i])
V'[4,i] = AESRound(V[3,i], V[4,i] ^ m1[i])
V'[5,i] = AESRound(V[4,i], V[5,i])
V'[6,i] = AESRound(V[5,i], V[6,i])
V'[7,i] = AESRound(V[6,i], V[7,i])
V[0,i] = V'[0,i]
V[1,i] = V'[1,i]
V[2,i] = V'[2,i]
V[3,i] = V'[3,i]
V[4,i] = V'[4,i]
V[5,i] = V'[5,i]
V[6,i] = V'[6,i]
V[7,i] = V'[7,i]
5.4.3. The Absorb Function
Absorb(ai)
The Absorb function is similar to the AEGIS-128L Absorb function, but
absorbs R bits instead of 256 bits.
Steps:
t0, t1 = Split(ai, R)
Update(t0, t1)
5.4.4. The Enc Function
Enc(xi)
The Enc function is similar to the AEGIS-128L Enc function, but
encrypts R bits instead of 256 bits.
Steps:
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z0 = {}
z1 = {}
for i in 0..D:
z0 = z0 || (V[6,i] ^ V[1,i] ^ (V[2,i] & V[3,i]))
z1 = z1 || (V[2,i] ^ V[5,i] ^ (V[6,i] & V[7,i]))
t0, t1 = Split(xi, R)
out0 = t0 ^ z0
out1 = t1 ^ z1
Update(t0, t1)
ci = out0 || out1
return ci
5.4.5. The Dec Function
Dec(ci)
The Dec function is similar to the AEGIS-128L Dec function, but
decrypts R bits instead of 256 bits.
Steps:
z0 = {}
z1 = {}
for i in 0..D:
z0 = z0 || (V[6,i] ^ V[1,i] ^ (V[2,i] & V[3,i]))
z1 = z1 || (V[2,i] ^ V[5,i] ^ (V[6,i] & V[7,i]))
t0, t1 = Split(ci, R)
out0 = t0 ^ z0
out1 = t1 ^ z1
Update(out0, out1)
xi = out0 || out1
return xi
5.4.6. The DecPartial Function
DecPartial(cn)
The DecPartial function is similar to the AEGIS-128L DecPartial
function, but decrypts up to R bits instead of 256 bits.
Steps:
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z0 = {}
z1 = {}
for i in 0..D:
z0 = z0 || (V[6,i] ^ V[1,i] ^ (V[2,i] & V[3,i]))
z1 = z1 || (V[2,i] ^ V[5,i] ^ (V[6,i] & V[7,i]))
t0, t1 = Split(ZeroPad(cn, R), 128 * D)
out0 = t0 ^ z0
out1 = t1 ^ z1
xn = Truncate(out0 || out1, |cn|)
v0, v1 = Split(ZeroPad(xn, R), 128 * D)
Update(v0, v1)
return xn
5.4.7. The Finalize Function
Finalize(ad_len_bits, msg_len_bits)
The Finalize function finalizes every AEGIS-128L instance and
combines the resulting authentication tags using the bitwise
exclusive OR operation.
Steps:
t = {}
u = LE64(ad_len_bits) || LE64(msg_len_bits)
for i in 0..D:
t = t || (V[2,i] ^ u)
Repeat(7, Update(t, t))
if tag_length == 16: # 128 bits
tag = ZeroPad({}, 128)
for i in 0..D:
tag = tag ^ V[0,i] ^ V[1,i] ^ V[2,i] ^ V[3,i] ^ V[4,i] ^ V[5,i] ^ V[6,i]
else: # 256 bits
tag0 = ZeroPad({}, 128)
tag1 = ZeroPad({}, 128)
for i in 0..D:
tag0 = tag0 ^ V[0,i] ^ V[1,i] ^ V[2,i] ^ V[3,i]
tag1 = tag1 ^ V[4,i] ^ V[5,i] ^ V[6,i] ^ V[7,i]
tag = tag0 || tag1
return tag
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5.5. AEGIS-256X
5.5.1. The Init Function
Init(key, nonce)
The Init function initializes a vector of D AEGIS-256 states with the
same key and nonce but a different context ctx[i]. The context is
added to the state before every update.
Steps:
k0, k1 = Split(key, 128)
n0, n1 = Split(nonce, 128)
for i in 0..D:
V[0,i] = k0 ^ n0
V[1,i] = k1 ^ n1
V[2,i] = C1
V[3,i] = C0
V[4,i] = k0 ^ C0
V[5,i] = k1 ^ C1
k0_v, k1_v = {}, {}
k0n0_v, k1n1_v = {}, {}
for i in 0..D:
k0_v = k0_v || k0
k1_v = k1_v || k1
k0n0_v = k0n0_v || (k0 ^ n0)
k1n1_v = k1n1_v || (k1 ^ n1)
Repeat(4,
for i in 0..D:
ctx[i] = ZeroPad(Byte(i) || Byte(D - 1), 128)
V[3,i] = V[3,i] ^ ctx[i]
V[5,i] = V[5,i] ^ ctx[i]
Update(k0_v)
V[3,i] = V[3,i] ^ ctx[i]
V[5,i] = V[5,i] ^ ctx[i]
Update(k1_v)
V[3,i] = V[3,i] ^ ctx[i]
V[5,i] = V[5,i] ^ ctx[i]
Update(k0n0_v)
V[3,i] = V[3,i] ^ ctx[i]
V[5,i] = V[5,i] ^ ctx[i]
Update(k1n1_v)
)
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5.5.2. The Update Function
Update(M)
The AEGIS-256X Update function is similar to the AEGIS-256 Update
function, but absorbs R (128 * D) bits at once. M is 128 * D bits
instead of 128 bits and is split into 128-bit blocks, each of them
updating a different AEGIS-256 state.
Steps:
m = Split(M, 128)
for i in 0..D:
V'[0,i] = AESRound(V[5,i], V[0,i] ^ m[i])
V'[1,i] = AESRound(V[0,i], V[1,i])
V'[2,i] = AESRound(V[1,i], V[2,i])
V'[3,i] = AESRound(V[2,i], V[3,i])
V'[4,i] = AESRound(V[3,i], V[4,i])
V'[5,i] = AESRound(V[4,i], V[5,i])
V[0,i] = V'[0,i]
V[1,i] = V'[1,i]
V[2,i] = V'[2,i]
V[3,i] = V'[3,i]
V[4,i] = V'[4,i]
V[5,i] = V'[5,i]
5.5.3. The Absorb Function
Absorb(ai)
The Absorb function is similar to the AEGIS-256 Absorb function, but
absorbs R bits instead of 128 bits.
Steps:
Update(ai)
5.5.4. The Enc Function
Enc(xi)
The Enc function is similar to the AEGIS-256 Enc function, but
encrypts R bits instead of 128 bits.
Steps:
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z = {}
for i in 0..D:
z = z || (V[1,i] ^ V[4,i] ^ V[5,i] ^ (V[2,i] & V[3,i]))
Update(xi)
ci = xi ^ z
return ci
5.5.5. The Dec Function
Dec(ci)
The Dec function is similar to the AEGIS-256 Dec function, but
decrypts R bits instead of 128 bits.
Steps:
z = {}
for i in 0..D:
z = z || (V[1,i] ^ V[4,i] ^ V[5,i] ^ (V[2,i] & V[3,i]))
xi = ci ^ z
Update(xi)
return xi
5.5.6. The DecPartial Function
DecPartial(cn)
The DecPartial function is similar to the AEGIS-256 DecPartial
function, but decrypts up to R bits instead of 128 bits.
Steps:
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z = {}
for i in 0..D:
z = z || (V[1,i] ^ V[4,i] ^ V[5,i] ^ (V[2,i] & V[3,i]))
t = ZeroPad(cn, R)
out = t ^ z
xn = Truncate(out, |cn|)
v = ZeroPad(xn, 128 * D)
Update(v)
return xn
5.5.7. The Finalize Function
Finalize(ad_len_bits, msg_len_bits)
The Finalize function finalizes every AEGIS-256 instance and combines
the resulting authentication tags using the bitwise exclusive OR
operation.
Steps:
t = {}
u = LE64(ad_len_bits) || LE64(msg_len_bits)
for i in 0..D:
t = t || (V[3,i] ^ u)
Repeat(7, Update(t))
if tag_length == 16: # 128 bits
tag = ZeroPad({}, 128)
for i in 0..D:
tag = tag ^ V[0,i] ^ V[1,i] ^ V[2,i] ^ V[3,i] ^ V[4,i] ^ V[5,i]
else: # 256 bits
tag0 = ZeroPad({}, 128)
tag1 = ZeroPad({}, 128)
for i in 0..D:
tag0 = tag0 ^ V[0,i] ^ V[1,i] ^ V[2,i]
tag1 = tag1 ^ V[3,i] ^ V[4,i] ^ V[5,i]
tag = tag0 || tag1
return tag
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5.6. Implementation Considerations
AEGIS-128X and AEGIS-256X with a degree of 1 are identical to AEGIS-
128L and AEGIS-256. This property can be used to reduce the code
size of a generic implementation.
In AEGIS-128X, V can be represented as eight 256-bit registers (when
D = 2) or eight 512-bit registers (when D = 4). In AEGIS-256X, V can
be represented as six 256-bit registers (when D = 2) or six 512-bit
registers (when D = 4). With this representation, loops over 0..D in
the above pseudocode can be replaced by vector instructions.
5.7. Operational Considerations
The AEGIS parallel modes are specialized and can only improve
performance on specific CPUs.
The degrees of parallelism implementations are encouraged to support
are 2 (for CPUs with 256-bit registers) and 4 (for CPUs with 512-bit
registers). The resulting algorithms are called AEGIS-128X2, AEGIS-
128X4, AEGIS-256X2, and AEGIS-256X4.
The following table summarizes how many bits are processed in
parallel (rate), the memory requirements (state size), and the
minimum vector register sizes a CPU should support for optimal
performance.
+=============+=============+=======================+============+
| Algorithm | Rate (bits) | Optimal Register Size | State Size |
| | | | (bits) |
+=============+=============+=======================+============+
| AEGIS-128L | 256 | 128 bits | 1024 |
+-------------+-------------+-----------------------+------------+
| AEGIS-128X2 | 512 | 256 bits | 2048 |
+-------------+-------------+-----------------------+------------+
| AEGIS-128X4 | 1024 | 512 bits | 4096 |
+-------------+-------------+-----------------------+------------+
| AEGIS-256 | 128 | 128 bits | 768 |
+-------------+-------------+-----------------------+------------+
| AEGIS-256X2 | 256 | 256 bits | 1536 |
+-------------+-------------+-----------------------+------------+
| AEGIS-256X4 | 512 | 512 bits | 3072 |
+-------------+-------------+-----------------------+------------+
Table 1
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Note that architectures with smaller vector registers but with many
registers and large pipelines may still benefit from the parallel
modes.
Protocols SHOULD opt for a parallel mode only when all the involved
parties agree on a specific variant. AEGIS-128L and AEGIS-256 SHOULD
remain the default choices.
Implementations MAY choose not to include the parallel AEGIS modes.
6. Encoding (ct, tag) Tuples
Applications MAY keep the ciphertext and the authentication tag in
distinct structures or encode both as a single string.
In the latter case, the tag MUST immediately follow the ciphertext:
combined_ct = ct || tag
7. AEGIS as a Stream Cipher
All AEGIS variants can also be used as stream ciphers.
Stream(len, key, nonce)
The Stream function expands a key and an optional nonce into a
variable-length, secure keystream.
Inputs:
* len: the length of the keystream to generate in bits.
* key: the AEGIS key.
* nonce: the nonce. If unspecified, it is set to N_MAX zero bytes.
Outputs:
* stream: the keystream.
Steps:
stream, tag = Encrypt(ZeroPad({}, len), {}, key, nonce)
return stream
This is equivalent to encrypting a len all-zero bits message without
associated data, and discarding the authentication tag.
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Instead of relying on the generic Encrypt function, implementations
can skip the finalization step.
After initialization, the Update function is called with constant
parameters, allowing further optimizations.
8. Implementation Status
_This note is to be removed before publishing as an RFC._
Multiple implementations of the schemes described in this document
have been developed and verified for interoperability.
A comprehensive list of known implementations and integrations can be
found at https://github.com/cfrg/draft-irtf-cfrg-aegis-aead, which
includes reference implementations closely aligned with the
pseudocode provided in this document.
9. Security Considerations
9.1. Usage Guidelines
9.1.1. Key and Nonce Selection
All AEGIS variants MUST be used in a nonce-respecting setting: for a
given key, a nonce MUST only be used once. Failure to do so would
immediately reveal the bitwise difference between two messages.
Every key MUST be randomly chosen from a uniform distribution.
The nonce MAY be public or predictable. It can be a counter, the
output of a permutation, or a generator with a long period.
With AEGIS-128L and AEGIS-128X, random nonces can safely encrypt up
to 2^48 messages using the same key with negligible (~ 2^-33, to
align with NIST guidelines) collision probability.
With AEGIS-256 and AEGIS-256X, random nonces can be used with no
practical limits.
9.1.2. Key Commitment
An authentication tag may verify under multiple keys, nonces, or
associated data, but AEGIS is assumed to be key committing in the
receiver-binding game, preventing common attacks when used with low-
entropy keys such as passwords. Finding distinct keys and/or nonces
that successfully verify the same (ad, ct, tag) tuple is expected to
require ~2^64 attempts with a 128-bit authentication tag and ~2^128
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attempts with a 256-bit tag.
It is fully committing in the restricted setting where an adversary
cannot control the associated data. As shown in [IR23], with the
ability to alter the associated data, it is possible to efficiently
find multiple keys that will verify the same authenticated
ciphertext.
Protocols mandating a fully committing scheme without that
restriction can provide the associated data as input to a
cryptographic hash function and use the output as the ad parameter of
the Encrypt and Decrypt functions. The selected hash function must
ensure a minimum of 128-bit preimage resistance. An instance of such
a function is SHA-256 [RFC6234].
9.1.3. Multi-User Security
AEGIS nonces match the size of the key. AEGIS-128L and AEGIS-128X
feature 128-bit nonces, offering an extra 32 bits compared to the
commonly used AEADs in IETF protocols. The AEGIS-256 and AEGIS-256X
variants provide even larger nonces. With 192 random bits, 64 bits
remain available to optionally encode additional information.
In all these variants, unused nonce bits can encode a key identifier,
enhancing multi-user security. If every key has a unique identifier,
multi-target attacks don’t provide any advantage over single-target
attacks.
9.1.4. Other Uses of AEGIS
All variants can be used as a MAC by calling the Encrypt() function
with the message as the ad and leaving msg empty, resulting in just a
tag. However, they MUST NOT be used as a hash function; if the key
is known, inputs generating state collisions can easily be crafted.
Similarly, as opposed to hash-based MACs, tags MUST NOT be used for
key derivation as there is no proof they are uniformly random.
9.2. Implementation Security
If tag verification fails, the unverified plaintext and the computed
message authentication tag MUST NOT be released. As shown in [VV18],
even a partial leak of the plaintext without verification would
facilitate chosen ciphertext attacks.
The security of AEGIS against timing and physical attacks is limited
by the implementation of the underlying AESRound() function. Failure
to implement AESRound() in a fashion safe against timing and physical
attacks, such as differential power analysis, timing analysis, or
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fault injection attacks, may lead to leakage of secret key material
or state information. The exact mitigations required for timing and
physical attacks also depend on the threat model in question.
Regardless of the variant, the key and nonce are only required by the
Init function; other functions only depend on the resulting state.
Therefore, implementations can overwrite ephemeral keys with zeros
right after the last Update call of the initialization function.
9.3. Security Guarantees
AEGIS-256 offers 256-bit message security against plaintext and state
recovery, whereas AEGIS-128L offers 128-bit security.
Under the assumption that the secret key is unknown to the attacker,
all AEGIS variants target 128-bit security against forgery attacks
regardless of the tag size.
Encrypting the same message with the same key and nonce but different
associated data generates distinct ciphertexts that do not reveal any
additional information about the message.
AEGIS has been shown to have reforgeability resilience in [FLLW17].
Without the ability to set the associated data, a successful forgery
does not increase the probability of subsequent forgeries.
AEGIS-128X and AEGIS-256X share the same security properties and
requirements as AEGIS-128L and AEGIS-256 respectively. In
particular, the security level and usage limits remain the same
[D23].
AEGIS is considered secure against guess-and-determine attacks aimed
at recovering the state from observed ciphertexts. This resilience
extends to quantum adversaries in the Q1 model, wherein quantum
attacks do not confer any practical advantage for decrypting
previously recorded ciphertexts or achieving key recovery.
Security analyses of AEGIS can be found in [AEGIS], [M14], [FLLW17],
[ENP19], [LIMS21], [JLD21], [STSI23], [IR23], and [BS23].
10. IANA Considerations
IANA has assigned the following identifiers in the AEAD Algorithms
Registry:
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+================+====+
| Algorithm Name | ID |
+================+====+
| AEAD_AEGIS128L | 32 |
+----------------+----+
| AEAD_AEGIS256 | 33 |
+----------------+----+
Table 2: AEGIS entries
in the AEAD Algorithms
Registry
IANA is requested to update the references of these entries to refer
to the final version of this document.
IANA is also requested to register the following identifiers in the
AEAD Algorithms Registry:
* AEAD_AEGIS128X2
* AEAD_AEGIS128X4
* AEAD_AEGIS256X2
* AEAD_AEGIS256X4
11. References
11.1. Normative References
[FIPS-AES] NIST, "Advanced encryption standard (AES)", NIST Federal
Information Processing Standards Publications 197,
DOI 10.6028/NIST.FIPS.197, November 2001,
<https://nvlpubs.nist.gov/nistpubs/FIPS/
NIST.FIPS.197.pdf>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC5116] McGrew, D., "An Interface and Algorithms for Authenticated
Encryption", RFC 5116, DOI 10.17487/RFC5116, January 2008,
<https://www.rfc-editor.org/rfc/rfc5116>.
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[RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
(SHA and SHA-based HMAC and HKDF)", RFC 6234,
DOI 10.17487/RFC6234, May 2011,
<https://www.rfc-editor.org/rfc/rfc6234>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
11.2. Informative References
[AEGIS] Wu, H. and B. Preneel, "AEGIS: A Fast Authenticated
Encryption Algorithm (v1.1)", 2016,
<https://competitions.cr.yp.to/round3/aegisv11.pdf>.
[BS23] Bonnetain, X. and A. Schrottenloher, "Single-query Quantum
Hidden Shift Attacks", Cryptology ePrint Archive, Paper
2023/1306, 2023, <https://eprint.iacr.org/2023/1306>.
[D23] Denis, F., "Adding more parallelism to the AEGIS
authenticated encryption algorithms", Cryptology ePrint
Archive, Paper 2023/523, 2023,
<https://eprint.iacr.org/2023/523>.
[ENP19] Eichlseder, M., Nageler, M., and R. Primas, "Analyzing the
Linear Keystream Biases in AEGIS", IACR Transactions on
Symmetric Cryptology, 2019(4), pp. 348–368,
DOI 10.13154/tosc.v2019.i4.348-368, 2020,
<https://doi.org/10.13154/tosc.v2019.i4.348-368>.
[FLLW17] Forler, C., List, E., Lucks, S., and J. Wenzel,
"Reforgeability of Authenticated Encryption Schemes",
Cryptology ePrint Archive, Paper 2017/332, 2017,
<https://eprint.iacr.org/2017/332>.
[IR23] Isobe, T. and M. Rahman, "Key Committing Security Analysis
of AEGIS", Cryptology ePrint Archive, Paper 2023/1495,
2023, <https://eprint.iacr.org/2023/1495>.
[JLD21] Jiao, L., Li, Y., and S. Du, "Guess-and-Determine Attacks
on AEGIS", The Computer Journal, vol 65, 2022(8), pp.
2221–2230, DOI 10.1093/comjnl/bxab059, 2021,
<https://doi.org/10.1093/comjnl/bxab059>.
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[LGR21] Len, J., Grubbs, P., and T. Ristenpart, "Partitioning
Oracle Attacks", 30th USENIX Security Symposium (USENIX
Security 21), pp. 195–212, 2021,
<https://www.usenix.org/conference/usenixsecurity21/
presentation/len>.
[LIMS21] Liu, F., Isobe, T., Meier, W., and K. Sakamoto, "Weak Keys
in Reduced AEGIS and Tiaoxin", IACR Transactions on
Symmetric Cryptology, 2021(2), pp. 104–139,
DOI 10.46586/tosc.v2021.i2.104-139, 2021,
<https://doi.org/10.46586/tosc.v2021.i2.104-139>.
[M14] Minaud, B., "Linear Biases in AEGIS Keystream", Selected
Areas in Cryptography. SAC 2014. Lecture Notes in Computer
Science, vol 8781, pp. 290–305,
DOI 10.1007/978-3-319-13051-4_18, 2014,
<https://doi.org/10.1007/978-3-319-13051-4_18>.
[STSI23] Shiraya, T., Takeuchi, N., Sakamoto, K., and T. Isobe,
"MILP-based security evaluation for AEGIS/Tiaoxin-346/
Rocca", IET Information Security, vol 17, 2023(3), pp.
458-467, DOI 10.1049/ise2.12109, 2023,
<https://doi.org/10.1049/ise2.12109>.
[VV18] Vaudenay, S. and D. Vizár, "Can Caesar Beat Galois?",
Applied Cryptography and Network Security. ACNS 2018.
Lecture Notes in Computer Science, vol 10892, pp. 476–494,
DOI 10.1007/978-3-319-93387-0_25, 2018,
<https://doi.org/10.1007/978-3-319-93387-0_25>.
Appendix A. Test Vectors
A.1. AESRound Test Vector
in : 000102030405060708090a0b0c0d0e0f
rk : 101112131415161718191a1b1c1d1e1f
out : 7a7b4e5638782546a8c0477a3b813f43
A.2. AEGIS-128L Test Vectors
A.2.1. Update Test Vector
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S0 : 9b7e60b24cc873ea894ecc07911049a3
S1 : 330be08f35300faa2ebf9a7b0d274658
S2 : 7bbd5bd2b049f7b9b515cf26fbe7756c
S3 : c35a00f55ea86c3886ec5e928f87db18
S4 : 9ebccafce87cab446396c4334592c91f
S5 : 58d83e31f256371e60fc6bb257114601
S6 : 1639b56ea322c88568a176585bc915de
S7 : 640818ffb57dc0fbc2e72ae93457e39a
M0 : 033e6975b94816879e42917650955aa0
M1 : 033e6975b94816879e42917650955aa0
After Update:
S0 : 596ab773e4433ca0127c73f60536769d
S1 : 790394041a3d26ab697bde865014652d
S2 : 38cf49e4b65248acd533041b64dd0611
S3 : 16d8e58748f437bfff1797f780337cee
S4 : 69761320f7dd738b281cc9f335ac2f5a
S5 : a21746bb193a569e331e1aa985d0d729
S6 : 09d714e6fcf9177a8ed1cde7e3d259a6
S7 : 61279ba73167f0ab76f0a11bf203bdff
A.2.2. Test Vector 1
key : 10010000000000000000000000000000
nonce : 10000200000000000000000000000000
ad :
msg : 00000000000000000000000000000000
ct : c1c0e58bd913006feba00f4b3cc3594e
tag128: abe0ece80c24868a226a35d16bdae37a
tag256: 25835bfbb21632176cf03840687cb968
cace4617af1bd0f7d064c639a5c79ee4
A.2.3. Test Vector 2
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key : 10010000000000000000000000000000
nonce : 10000200000000000000000000000000
ad :
msg :
ct :
tag128: c2b879a67def9d74e6c14f708bbcc9b4
tag256: 1360dc9db8ae42455f6e5b6a9d488ea4
f2184c4e12120249335c4ee84bafe25d
A.2.4. Test Vector 3
key : 10010000000000000000000000000000
nonce : 10000200000000000000000000000000
ad : 0001020304050607
msg : 000102030405060708090a0b0c0d0e0f
101112131415161718191a1b1c1d1e1f
ct : 79d94593d8c2119d7e8fd9b8fc77845c
5c077a05b2528b6ac54b563aed8efe84
tag128: cc6f3372f6aa1bb82388d695c3962d9a
tag256: 022cb796fe7e0ae1197525ff67e30948
4cfbab6528ddef89f17d74ef8ecd82b3
A.2.5. Test Vector 4
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key : 10010000000000000000000000000000
nonce : 10000200000000000000000000000000
ad : 0001020304050607
msg : 000102030405060708090a0b0c0d
ct : 79d94593d8c2119d7e8fd9b8fc77
tag128: 5c04b3dba849b2701effbe32c7f0fab7
tag256: 86f1b80bfb463aba711d15405d094baf
4a55a15dbfec81a76f35ed0b9c8b04ac
A.2.6. Test Vector 5
key : 10010000000000000000000000000000
nonce : 10000200000000000000000000000000
ad : 000102030405060708090a0b0c0d0e0f
101112131415161718191a1b1c1d1e1f
20212223242526272829
msg : 101112131415161718191a1b1c1d1e1f
202122232425262728292a2b2c2d2e2f
3031323334353637
ct : b31052ad1cca4e291abcf2df3502e6bd
b1bfd6db36798be3607b1f94d34478aa
7ede7f7a990fec10
tag128: 7542a745733014f9474417b337399507
tag256: b91e2947a33da8bee89b6794e647baf0
fc835ff574aca3fc27c33be0db2aff98
A.2.7. Test Vector 6
This test MUST return a “verification failed” error.
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key : 10000200000000000000000000000000
nonce : 10010000000000000000000000000000
ad : 0001020304050607
ct : 79d94593d8c2119d7e8fd9b8fc77
tag128: 5c04b3dba849b2701effbe32c7f0fab7
tag256: 86f1b80bfb463aba711d15405d094baf
4a55a15dbfec81a76f35ed0b9c8b04ac
A.2.8. Test Vector 7
This test MUST return a “verification failed” error.
key : 10010000000000000000000000000000
nonce : 10000200000000000000000000000000
ad : 0001020304050607
ct : 79d94593d8c2119d7e8fd9b8fc78
tag128: 5c04b3dba849b2701effbe32c7f0fab7
tag256: 86f1b80bfb463aba711d15405d094baf
4a55a15dbfec81a76f35ed0b9c8b04ac
A.2.9. Test Vector 8
This test MUST return a “verification failed” error.
key : 10010000000000000000000000000000
nonce : 10000200000000000000000000000000
ad : 0001020304050608
ct : 79d94593d8c2119d7e8fd9b8fc77
tag128: 5c04b3dba849b2701effbe32c7f0fab7
tag256: 86f1b80bfb463aba711d15405d094baf
4a55a15dbfec81a76f35ed0b9c8b04ac
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A.2.10. Test Vector 9
This test MUST return a “verification failed” error.
key : 10010000000000000000000000000000
nonce : 10000200000000000000000000000000
ad : 0001020304050607
ct : 79d94593d8c2119d7e8fd9b8fc77
tag128: 6c04b3dba849b2701effbe32c7f0fab8
tag256: 86f1b80bfb463aba711d15405d094baf
4a55a15dbfec81a76f35ed0b9c8b04ad
A.3. AEGIS-256 Test Vectors
A.3.1. Update Test Vector
S0 : 1fa1207ed76c86f2c4bb40e8b395b43e
S1 : b44c375e6c1e1978db64bcd12e9e332f
S2 : 0dab84bfa9f0226432ff630f233d4e5b
S3 : d7ef65c9b93e8ee60c75161407b066e7
S4 : a760bb3da073fbd92bdc24734b1f56fb
S5 : a828a18d6a964497ac6e7e53c5f55c73
M : b165617ed04ab738afb2612c6d18a1ec
After Update:
S0 : e6bc643bae82dfa3d991b1b323839dcd
S1 : 648578232ba0f2f0a3677f617dc052c3
S2 : ea788e0e572044a46059212dd007a789
S3 : 2f1498ae19b80da13fba698f088a8590
S4 : a54c2ee95e8c2a2c3dae2ec743ae6b86
S5 : a3240fceb68e32d5d114df1b5363ab67
A.3.2. Test Vector 1
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key : 10010000000000000000000000000000
00000000000000000000000000000000
nonce : 10000200000000000000000000000000
00000000000000000000000000000000
ad :
msg : 00000000000000000000000000000000
ct : 754fc3d8c973246dcc6d741412a4b236
tag128: 3fe91994768b332ed7f570a19ec5896e
tag256: 1181a1d18091082bf0266f66297d167d
2e68b845f61a3b0527d31fc7b7b89f13
A.3.3. Test Vector 2
key : 10010000000000000000000000000000
00000000000000000000000000000000
nonce : 10000200000000000000000000000000
00000000000000000000000000000000
ad :
msg :
ct :
tag128: e3def978a0f054afd1e761d7553afba3
tag256: 6a348c930adbd654896e1666aad67de9
89ea75ebaa2b82fb588977b1ffec864a
A.3.4. Test Vector 3
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key : 10010000000000000000000000000000
00000000000000000000000000000000
nonce : 10000200000000000000000000000000
00000000000000000000000000000000
ad : 0001020304050607
msg : 000102030405060708090a0b0c0d0e0f
101112131415161718191a1b1c1d1e1f
ct : f373079ed84b2709faee373584585d60
accd191db310ef5d8b11833df9dec711
tag128: 8d86f91ee606e9ff26a01b64ccbdd91d
tag256: b7d28d0c3c0ebd409fd22b4416050307
3a547412da0854bfb9723020dab8da1a
A.3.5. Test Vector 4
key : 10010000000000000000000000000000
00000000000000000000000000000000
nonce : 10000200000000000000000000000000
00000000000000000000000000000000
ad : 0001020304050607
msg : 000102030405060708090a0b0c0d
ct : f373079ed84b2709faee37358458
tag128: c60b9c2d33ceb058f96e6dd03c215652
tag256: 8c1cc703c81281bee3f6d9966e14948b
4a175b2efbdc31e61a98b4465235c2d9
A.3.6. Test Vector 5
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key : 10010000000000000000000000000000
00000000000000000000000000000000
nonce : 10000200000000000000000000000000
00000000000000000000000000000000
ad : 000102030405060708090a0b0c0d0e0f
101112131415161718191a1b1c1d1e1f
20212223242526272829
msg : 101112131415161718191a1b1c1d1e1f
202122232425262728292a2b2c2d2e2f
3031323334353637
ct : 57754a7d09963e7c787583a2e7b859bb
24fa1e04d49fd550b2511a358e3bca25
2a9b1b8b30cc4a67
tag128: ab8a7d53fd0e98d727accca94925e128
tag256: a3aca270c006094d71c20e6910b5161c
0826df233d08919a566ec2c05990f734
A.3.7. Test Vector 6
This test MUST return a “verification failed” error.
key : 10000200000000000000000000000000
00000000000000000000000000000000
nonce : 10010000000000000000000000000000
00000000000000000000000000000000
ad : 0001020304050607
ct : f373079ed84b2709faee37358458
tag128: c60b9c2d33ceb058f96e6dd03c215652
tag256: 8c1cc703c81281bee3f6d9966e14948b
4a175b2efbdc31e61a98b4465235c2d9
A.3.8. Test Vector 7
This test MUST return a “verification failed” error.
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key : 10010000000000000000000000000000
00000000000000000000000000000000
nonce : 10000200000000000000000000000000
00000000000000000000000000000000
ad : 0001020304050607
ct : f373079ed84b2709faee37358459
tag128: c60b9c2d33ceb058f96e6dd03c215652
tag256: 8c1cc703c81281bee3f6d9966e14948b
4a175b2efbdc31e61a98b4465235c2d9
A.3.9. Test Vector 8
This test MUST return a “verification failed” error.
key : 10010000000000000000000000000000
00000000000000000000000000000000
nonce : 10000200000000000000000000000000
00000000000000000000000000000000
ad : 0001020304050608
ct : f373079ed84b2709faee37358458
tag128: c60b9c2d33ceb058f96e6dd03c215652
tag256: 8c1cc703c81281bee3f6d9966e14948b
4a175b2efbdc31e61a98b4465235c2d9
A.3.10. Test Vector 9
This test MUST return a “verification failed” error.
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key : 10010000000000000000000000000000
00000000000000000000000000000000
nonce : 10000200000000000000000000000000
00000000000000000000000000000000
ad : 0001020304050607
ct : f373079ed84b2709faee37358458
tag128: c60b9c2d33ceb058f96e6dd03c215653
tag256: 8c1cc703c81281bee3f6d9966e14948b
4a175b2efbdc31e61a98b4465235c2da
A.4. AEGIS-128X2 Test Vectors
A.4.1. Initial State
key : 000102030405060708090a0b0c0d0e0f
nonce : 101112131415161718191a1b1c1d1e1f
ctx[0]: 00010000000000000000000000000000
ctx[1]: 01010000000000000000000000000000
After initialization:
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V[0,0]: a4fc1ad9a72942fb88bd2cabbba6509a
V[0,1]: 80a40e392fc71084209b6c3319bdc6cc
V[1,0]: 380f435cf801763b1f0c2a2f7212052d
V[1,1]: 73796607b59b1b650ee91c152af1f18a
V[2,0]: 6ee1de433ea877fa33bc0782abff2dcb
V[2,1]: b9fab2ab496e16d1facaffd5453cbf14
V[3,0]: 85f94b0d4263bfa86fdf45a603d8b6ac
V[3,1]: 90356c8cadbaa2c969001da02e3feca0
V[4,0]: 09bd69ad3730174bcd2ce9a27cd1357e
V[4,1]: e610b45125796a4fcf1708cef5c4f718
V[5,0]: fcdeb0cf0a87bf442fc82383ddb0f6d6
V[5,1]: 61ad32a4694d6f3cca313a2d3f4687aa
V[6,0]: 571c207988659e2cdfbdaae77f4f37e3
V[6,1]: 32e6094e217573bf91fb28c145a3efa8
V[7,0]: ca549badf8faa58222412478598651cf
V[7,1]: 3407279a54ce76d2e2e8a90ec5d108eb
A.4.2. Test Vector 1
key : 000102030405060708090a0b0c0d0e0f
nonce : 101112131415161718191a1b1c1d1e1f
ad :
msg :
ct :
tag128: 63117dc57756e402819a82e13eca8379
tag256: b92c71fdbd358b8a4de70b27631ace90
cffd9b9cfba82028412bac41b4f53759
A.4.3. Test Vector 2
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key : 000102030405060708090a0b0c0d0e0f
nonce : 101112131415161718191a1b1c1d1e1f
ad : 0102030401020304
msg : 04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
0405060704050607
ct : 5795544301997f93621b278809d6331b
3bfa6f18e90db12c4aa35965b5e98c5f
c6fb4e54bcb6111842c20637252eff74
7cb3a8f85b37de80919a589fe0f24872
bc926360696739e05520647e390989e1
eb5fd42f99678a0276a498f8c454761c
9d6aacb647ad56be62b29c22cd4b5761
b38f43d5a5ee062
tag128: 1aebc200804f405cab637f2adebb6d77
tag256: c471876f9b4978c44f2ae1ce770cdb11
a094ee3feca64e7afcd48bfe52c60eca
A.5. AEGIS-128X4 Test Vectors
A.5.1. Initial State
key : 000102030405060708090a0b0c0d0e0f
nonce : 101112131415161718191a1b1c1d1e1f
ctx[0]: 00030000000000000000000000000000
ctx[1]: 01030000000000000000000000000000
ctx[2]: 02030000000000000000000000000000
ctx[3]: 03030000000000000000000000000000
After initialization:
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V[0,0]: 924eb07635003a37e6c6575ba8ce1929
V[0,1]: c8b6a5d91475445e936d48e794be0ce2
V[0,2]: fcd37d050e24084befe3bbb219d64760
V[0,3]: 2e9f58cfb893a8800220242c373a8b18
V[1,0]: 1a1f60c4fab64e5471dc72edfcf6fe6b
V[1,1]: c1e525ebea2d6375a9edd045dce96381
V[1,2]: 97a3e25abd228a44d4a14a6d3fe9185c
V[1,3]: c2d4cf7f4287a98744645674265d4ca8
V[2,0]: 7bb50c534f6ec4780530ff1cce8a16e8
V[2,1]: 7b08d57557da0b5ef7b5f7d98b0ba189
V[2,2]: 6bfcac34ddb68404821a4d665303cb0f
V[2,3]: d95626f6dfad1aed7467622c38529932
V[3,0]: af339fd2d50ee45fc47665c647cf6586
V[3,1]: d0669b39d140f0e118a4a511efe2f95a
V[3,2]: 7a94330f35c194fadda2a87e42cdeccc
V[3,3]: 233b640d1f4d56e2757e72c1a9d8ecb1
V[4,0]: 9f93737d699ba05c11e94f2b201bef5e
V[4,1]: 61caf387cf7cfd3f8300ac7680ccfd76
V[4,2]: 5825a671ecef03b7a9c98a601ae32115
V[4,3]: 87a1fe4d558161a8f4c38731f3223032
V[5,0]: 7a5aca78d636c05bbc702b2980196ab6
V[5,1]: 915d868408495d07eb527789f282c575
V[5,2]: d0947bfbc1d3309cdffc9be1503aea62
V[5,3]: 8834ea57a15b9fbdc0245464a4b8cbef
V[6,0]: e46f4cf71a95ac45b6f0823e3aba1a86
V[6,1]: 8c4ecef682fc44a8eba911b3fc7d99f9
V[6,2]: a4fb61e2c928a2ca760b8772f2ea5f2e
V[6,3]: 3d34ea89da73caa3016c280500a155a3
V[7,0]: 85075f0080e9d618e7eb40f57c32d9f7
V[7,1]: d2ab2b320c6e93b155a3787cb83e5281
V[7,2]: 0b3af0250ae36831a1b072e499929bcb
V[7,3]: 5cce4d00329d69f1aae36aa541347512
A.5.2. Test Vector 1
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key : 000102030405060708090a0b0c0d0e0f
nonce : 101112131415161718191a1b1c1d1e1f
ad :
msg :
ct :
tag128: 5bef762d0947c00455b97bb3af30dfa3
tag256: a4b25437f4be93cfa856a2f27e4416b4
2cac79fd4698f2cdbe6af25673e10a68
A.5.3. Test Vector 2
key : 000102030405060708090a0b0c0d0e0f
nonce : 101112131415161718191a1b1c1d1e1f
ad : 0102030401020304
msg : 04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
0405060704050607
ct : e836118562f4479c9d35c17356a83311
4c21f9aa39e4dda5e5c87f4152a00fce
9a7c38f832eafe8b1c12f8a7cf12a81a
1ad8a9c24ba9dedfbdaa586ffea67ddc
801ea97d9ab4a872f42d0e352e2713da
cd609f9442c17517c5a29daf3e2a3fac
4ff6b1380c4e46df7b086af6ce6bc1ed
594b8dd64aed2a7e
tag128: 0e56ab94e2e85db80f9d54010caabfb4
tag256: 69abf0f64a137dd6e122478d777e98bc
422823006cf57f5ee822dd78397230b2
A.6. AEGIS-256X2 Test Vectors
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A.6.1. Initial State
key : 000102030405060708090a0b0c0d0e0f
101112131415161718191a1b1c1d1e1f
nonce : 101112131415161718191a1b1c1d1e1f
202122232425262728292a2b2c2d2e2f
ctx[0]: 00010000000000000000000000000000
ctx[1]: 01010000000000000000000000000000
After initialization:
V[0,0]: eca2bf4538442e8712d4972595744039
V[0,1]: 201405efa9264f07911db58101903087
V[1,0]: 3e536a998799408a97f3479a6f779d48
V[1,1]: 0d79a7d822a5d215f78c3bf2feb33ae1
V[2,0]: cf8c63d6f2b4563cdd9231107c85950e
V[2,1]: 78d17ed7d8d563ff11bd202c76864839
V[3,0]: d7e0707e6bfbbad913bc94b6993a9fa0
V[3,1]: 097e4b1bff40d4c19cb29dfd125d62f2
V[4,0]: a373cf6d537dd66bc0ef0f2f9285359f
V[4,1]: c0d0ae0c48f9df3faaf0e7be7768c326
V[5,0]: 9f76560dcae1efacabdcce446ae283bc
V[5,1]: bd52a6b9c8f976a26ec1409df19e8bfe
A.6.2. Test Vector 1
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key : 000102030405060708090a0b0c0d0e0f
101112131415161718191a1b1c1d1e1f
nonce : 101112131415161718191a1b1c1d1e1f
202122232425262728292a2b2c2d2e2f
ad :
msg :
ct :
tag128: 62cdbab084c83dacdb945bb446f049c8
tag256: 25d7e799b49a80354c3f881ac2f1027f
471a5d293052bd9997abd3ae84014bb7
A.6.3. Test Vector 2
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key : 000102030405060708090a0b0c0d0e0f
101112131415161718191a1b1c1d1e1f
nonce : 101112131415161718191a1b1c1d1e1f
202122232425262728292a2b2c2d2e2f
ad : 0102030401020304
msg : 04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
0405060704050607
ct : 73110d21a920608fd77b580f1e442808
7a7365cb153b4eeca6b62e1a70f7f9a8
d1f31f17da4c3acfacb2517f2f5e1575
8c35532e33751a964d18d29a599d2dc0
7f9378339b9d8c9fa03d30a4d7837cc8
eb8b99bcbba2d11cd1a0f994af2b8f94
7ef18473bd519e5283736758480abc99
0e79d4ccab93dde9
tag128: 94a3bd44ad3381e36335014620ee638e
tag256: 0392c62b17ddb00c172a010b5a327d0f
97317b6fbaee31ef741f004d7adc1e81
A.7. AEGIS-256X4 Test Vectors
A.7.1. Initial State
key : 000102030405060708090a0b0c0d0e0f
101112131415161718191a1b1c1d1e1f
nonce : 101112131415161718191a1b1c1d1e1f
202122232425262728292a2b2c2d2e2f
ctx[0]: 00030000000000000000000000000000
ctx[1]: 01030000000000000000000000000000
ctx[2]: 02030000000000000000000000000000
ctx[3]: 03030000000000000000000000000000
After initialization:
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V[0,0]: 482a86e8436cd2361063a4b2702769b9
V[0,1]: d95a2be81c9245b22996f68eea0122f9
V[0,2]: 0c2a3b348b1a5e256c6751377318c41e
V[0,3]: f64436a21653fe7cf2e0829a177db383
V[1,0]: e705e8866267717d96092e58e78b574c
V[1,1]: d1dd412142df9806cc267af2fe1d830e
V[1,2]: 30e7dfd3c9941b8394e95bdf5bac99d9
V[1,3]: 9f27186f8a4fab86820689822c3c74d2
V[2,0]: e1aa6af5d9e31dde8d94a48a0810fa89
V[2,1]: 63555cdf0d98f18fb75b029ad80786c0
V[2,2]: a3ee0e4a3429a9539e4fcec385475608
V[2,3]: 28ea527d31ef61df498dc107fe02df99
V[3,0]: 37f06808410c8f3954525ae44584d3be
V[3,1]: 8fcc23bca2fe2209f93d34e2da35b33d
V[3,2]: 33156347df89eaa69ab11096362daccf
V[3,3]: bbe58d9dbe8c5b0469be5a87086db5d4
V[4,0]: d1c9eb37fecbc5ada7b351fa4f501f32
V[4,1]: 0b9b803283c1538628b507c8f6432434
V[4,2]: bfb8b6d4f87cce28825c7e92f54b8728
V[4,3]: 8917bb5b09c32f900c6a5a1d63c46264
V[5,0]: 4f6110c2ef0c3c687e90c1e5532ddf8e
V[5,1]: 031bd85d99f64684d23728a0453c72a1
V[5,2]: 10bc7ec34d4119b5bdeb6c7dfc458247
V[5,3]: 591ece530aeaa5c9867220156f5c25e3
A.7.2. Test Vector 1
key : 000102030405060708090a0b0c0d0e0f
101112131415161718191a1b1c1d1e1f
nonce : 101112131415161718191a1b1c1d1e1f
202122232425262728292a2b2c2d2e2f
ad :
msg :
ct :
tag128: 3b7fee6cee7bf17888ad11ed2397beb4
tag256: 6093a1a8aab20ec635dc1ca71745b01b
5bec4fc444c9ffbebd710d4a34d20eaf
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A.7.3. Test Vector 2
key : 000102030405060708090a0b0c0d0e0f
101112131415161718191a1b1c1d1e1f
nonce : 101112131415161718191a1b1c1d1e1f
202122232425262728292a2b2c2d2e2f
ad : 0102030401020304
msg : 04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
04050607040506070405060704050607
0405060704050607
ct : bec109547f8316d598b3b7d947ad4c0e
f5b98e217cffa0d858ad49ae34109a95
abc5b5fada820c4d6ae2fca0f5e2444e
52a04a1edb7bec71408de3e199500521
94506be3ba6a4de51a15a577ea0e4c14
f7539a13e751a555f48d0f49fecffb22
0525e60d381e2efa803b09b7164ba59f
dc66656affd51e06
tag128: ec44b512d713f745547be345bcc66b6c
tag256: ba3168ecd7f7120c5e204a7e0d616e39
5675ddfe00e4e5490a5ba93bb1a70555
Acknowledgments
The AEGIS authenticated encryption algorithm was invented by Hongjun
Wu and Bart Preneel.
The round function leverages the AES permutation invented by Joan
Daemen and Vincent Rijmen. They also authored the Pelican MAC that
partly motivated the design of the AEGIS MAC.
We would like to thank the following individuals for their
contributions:
* Eric Lagergren and Daniel Bleichenbacher for catching a broken
test vector and Daniel Bleichenbacher for many helpful
suggestions.
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* John Preuß Mattsson for his review of the draft, and for
suggesting how AEGIS should be used in the context of DTLS and
QUIC.
* Bart Mennink and Charlotte Lefevre as well as Takanori Isobe and
Mostafizar Rahman for investigating the commitment security of the
schemes specified in this document.
Authors' Addresses
Frank Denis
Fastly Inc.
Email: fde@00f.net
Samuel Lucas
Individual Contributor
Email: samuel-lucas6@pm.me
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