PKIX Working Group Daniel R. L. Brown,
INTERNET-DRAFT Certicom Corp.
Expires April 4, 2007 October 4, 2006
Additional Algorithms and Identifiers
for use of Elliptic Curve Cryptography with PKIX
<draft-ietf-pkix-ecc-pkalgs-03.txt>
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Copyright (C) The Internet Society (2006).
Abstract
This document gives additional algorithms and associated ASN.1
identifiers for elliptic curve cryptography (ECC) used with the
Internet X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile (PKIX). The algorithms
and identifiers here are consistent with both ANSI X9.62-2005 and
X9.63-2001, and shall be consistent with the forthcoming revisions
of these documents. Consistency shall also be maintained with SEC1
and SEC2, and any revisions or successors of such documents.
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Table of Contents
1 Introduction ............................................... 3
1.1 Terminology ........................................... 3
1.2 Elliptic Curve Cryptography ........................... 3
1.3 Algorithm Identifiers ................................. 4
2 Auxiliary Functions ........................................ 5
2.1 Hash Functions ........................................ 5
2.2 Key Derivation Functions .............................. 6
2.3 Key Wrap Functions .................................... 7
2.4 Message Authentication Codes .......................... 8
2.5 Key Confirmation Methods ... .......................... 9
3 Elliptic Curve Domain Parameters ...........................10
4 ECC Algorithms ............................................ 12
4.1 Signature Schemes .................................... 12
4.1.1 ECDSA ........................................... 12
4.2 Key Agreement Schemes ................................ 14
4.2.1 1-Pass ECDH ..................................... 14
4.2.2 Full and 1-Pass ECMQV ........................... 15
4.3 ECC Algorithm Set .................................... 17
5 ECC Keys .................................................. 17
5.1 Public Keys .......................................... 17
5.2 Private Keys ......................................... 19
6 ASN.1 Module .............................................. 19
7 References ................................................ 20
8 Security Considerations ................................... 21
9 Acknowledgments ........................................... 21
10 Authors' Addresses ........................................ 21
11 Full Copyright Statement .................................. 21
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1 Introduction
This document supplements [RFC 3279], "Algorithms and
Identifiers for the Internet X.509 Public Key Infrastructure
Certificate and Certificate Revocation List (CRL) Profile "
This document specifies supplementary algorithm identifiers and
ASN.1 encoding formats for digital signatures and subject public
keys used in the Internet X.509 Public Key Infrastructure (PKIX).
The supplementary formats specified are used to indicate the
auxiliary functions, such as the new hash functions specified in
[FIPS 180-2] including SHA-256, that are to be used with elliptic
curve public keys.
Furthermore, this document specifies formats to indicate that an
elliptic curve public key is to be restricted for use with an
indicated set of elliptic curve cryptography algorithms.
Note: Previous standards, such as [X9.63] and [SEC1], suggested
that the extended key usage field could be used for purposes above.
Because such a practice was regarded as improper, a new means to
accomplish the objectives is being introduced both in this document
and revisions of the standards above.
1.1 Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in [RFC 2119].
1.2 Elliptic Curve Cryptography
Elliptic Curve Cryptography (ECC) is a family of cryptographic
algorithms. Several algorithms, such as Diffie-Hellman (DH) key
agreement and the Digital Signature Algorithm (DSA), have analogues
in ECC. The analogy is that the cryptographic group is an elliptic
curve group over a finite field rather the multiplicative group of
(invertible) integers modulo a large prime.
Because an EC group and its elements are different from DH and DSA
groups and elements, ECC requires a slightly different syntax from
DSA and DH.
Because a single ECC public key in a certificate might
potentially be used for multiple different ECC algorithms, a
mechanism for indicating algorithm usage is important.
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1.3 Algorithm Identifiers
The parameters field of the ASN.1 type AlgorithmIdentifier is
optional when using ECC. When the parameters field is not used
meaningfully, it SHOULD be absent, but MAY be NULL if it is
necessary to interoperate with legacy implementations that do not
support an optional parameters field. Absent and NULL parameters
SHOULD both be accepted as valid and MUST then be considered to
have the same meaning.
The following ASN.1 information object class helps to parameterize
the AlgorithmIdentifier type with sets of legal values.
ALGORITHM ::= CLASS {
&id OBJECT IDENTIFIER UNIQUE,
&Type OPTIONAL
}
WITH SYNTAX { OID &id [PARMS &Type] }
The type AlgorithmIdentifier is parameterized to allow legal sets
of values to be specified by constraining the type with an
information object set.
AlgorithmIdentifier {ALGORITHM:IOSet} ::= SEQUENCE {
algorithm ALGORITHM.&id({IOSet}),
parameters ALGORITHM.&Type({IOSet}{@algorithm}) OPTIONAL
}
In practice, AlgorithmIdentifier is a sequence of an OID and an
optional second field with syntax depending on the OID. In this
document, the use of AlgorithmIdentifier will be constrained form.
For example, when a hash function needs to be identified, a
constrained form of AlgorithmIdentifier is used that only permits
the OIDs for hash functions. The constraints also dictate the
syntax for the parameters field for a given OID. Constraints are
useful for disallowing insertion of illegal OIDs and for more
efficient PER encoding.
Note: Older syntax for AlgorithmIdentifier had a mandatory
parameters field, which was customarily set to NULL when parameters
field had nothing to convey. However, in the new syntax, in such
situations the absent parameters are preferred to NULL parameters
when the parameters field does not carry any meaning. This
document specifies exactly what is permitted in the parameters
field.
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2 Auxiliary Functions
A number of different auxiliary functions are used in ECC. When
two entities use an ECC algorithm in their communications with each
other, they need to use matching auxiliary functions in order to
successfully interoperate. Standards for ECC generally recommend
or require certain choices of auxiliary functions, usually
according to the elliptic curve key size in use. The following
syntax helps to indicate, if needed, which auxiliary functions are
to be used.
2.1 Hash Functions
Most notable among the auxiliary functions are hash functions,
which are used in several different ways: message digesting for
signatures, verifiably random domain parameter generation, building
key derivation functions, building message authentication codes, as
well as building random number generators.
The hash functions SHA-1, SHA-224, SHA-256, SHA-384 and SHA-512 can
be used with ECC. They are specified in [FIPS 180-2].
Hash functions are identified with the following object
identifiers.
sha-1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)
oiw(14) secsig(3) algorithm(2) sha1(26) }
id-sha224 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16)
us(840) organization(1) gov(101) csor(3) nistalgorithm(4)
hashalgs(2) 4 }
id-sha256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16)
us(840) organization(1) gov(101) csor(3) nistalgorithm(4)
hashalgs(2) 1 }
id-sha384 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16)
us(840) organization(1) gov(101) csor(3) nistalgorithm(4)
hashalgs(2) 2 }
id-sha512 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16)
us(840) organization(1) gov(101) csor(3) nistalgorithm(4)
hashalgs(2) 3 }
Others may be added.
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The following information object set is used to constrain the
AlgorithmIdentifier type for hash functions.
HashFunctions ALGORITHM ::= {
{OID sha-1} | {OID sha-1 PARMS NULL } |
{OID id-sha224} | {OID id-sha224 PARMS NULL } |
{OID id-sha256} | {OID id-sha256 PARMS NULL } |
{OID id-sha384} | {OID id-sha384 PARMS NULL } |
{OID id-sha512} | {OID id-sha512 PARMS NULL } ,
... -- Additional hashes may be added
}
The constrained AlgorithmIdentifier syntax to identify a hash
function is:
HashAlgorithm ::= AlgorithmIdentifier {{HashFunctions}}
The parameters SHOULD be absent but MAY be NULL.
2.2 Key Derivation Functions
<<< Rough version, only. Anticipate using a more flexible
syntax in next update of this draft ... >>>
Crucial to key establishment, a Key Derivation Function (KDF) takes
input of a raw elliptic curve point and other information such as
identifiers, and then derives a key. A KDF helps to eliminate any
structure from the key. (Elliptic curve points generally have some
structure and cannot be regarded as pseudorandom.)
The KDFs to use with ECC are specified in [X9.63], except that the
hash function SHA-1 can be replaced by one of SHA-1, SHA-224,
SHA-256, SHA-384, or SHA-512, and in [SP 800-56]. In particular,
the KDF is determined entirely by the hash function it is built
from, so the following syntax is adopted.
KeyDerivationFunction ::= HashAlgorithm
That certain protocols might use a different KDF, such as KDF1 in
IEEE 1363-2000, only means that the specifications here are
overridden in these protocols. Such KDFs ought to be deprecated.
No ASN.1 syntax is given here to support such KDFs, making
protocols that use such KDFs provide their own mechanisms to
indicate use of them.
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2.3 Key Wrap Functions
Key wrap functions can be used to transform a key agreement scheme
into a key transport scheme.
The following constrained algorithm identifier is used to identify
a key wrap algorithm.
KeyWrapAlgorithm ::=
AlgorithmIdentifier {{ KeyWrapAlgorithms }}
The information object set used to constrain the algorithm
identifier for key wrap algorithms is
KeyWrapAlgorithms ::= ALGORITHM {
{OID id-tdes-wrap } |
{OID id-aes128-wrap } |
{OID id-aes192-wrap } |
{OID id-aes256-wrap } ,
... -- More may be added
}
The object identifiers above are
id-tdes-wrap OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840)
rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) alg(3) 6 }
id-ase128-wrap OBJECT IDENTIFIER ::= { nistAlgorithm aes(1)
aes128-Wrap(5) }
id-ase192-wrap OBJECT IDENTIFIER ::= { nistAlgorithm aes(1)
aes128-Wrap(5) }
id-ase256-wrap OBJECT IDENTIFIER ::= { nistAlgorithm aes(1)
aes128-Wrap(5) }
where the base object identifier used above is
nistAlgorithm OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)
country(16) us(840) organization(1) gov(101) csor(3)
nistAlgorithm(4) }
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2.4 Message Authentication Codes
Some ECC algorithms use a Message Authentication Code (MAC), for
example, as part of key confirmation.
The following constrainted algorithm identifier syntax is used to
identify use of a MAC:
MessageAuthenticationCode ::=
AlgorithmIdentifier {{ MessageAuthenticationCodes }}
The infomation object set defining the constraints is given is by
MessageAuthenticationCodes ::= ALGORITHM {
{OID id-hmac-sha1} |
{OID id-hmac-sha1 PARMS INTEGER} |
{OID id-hmac-sha224} |
{OID id-hmac-sha224 PARMS INTEGER} |
{OID id-hmac-sha256} |
{OID id-hmac-sha256 PARMS INTEGER} |
{OID id-hmac-sha384} |
{OID id-hmac-sha384 PARMS INTEGER} |
{OID id-hmac-sha512} |
{OID id-hmac-sha512 PARMS INTEGER},
... -- More MACs may be added
}
The optional parameter is use to indicate that the the HMAC output
should be truncated.
Example candidates for future expansion include GCM and UMAC.
The following object identifiers identify a specific MAC.
id-hmac-sha1 OBJECT IDENTIFIER ::= {
iso(1) identified-organization(3) dod(6)
internet(1) security(5) mechanisms(5) 8 1 2 }
id-hmac-sha224 OBJECT IDENTIFIER ::= {id-hmac 8}
id-hmac-sha256 OBJECT IDENTIFIER ::= {id-hmac 9}
id-hmac-sha384 OBJECT IDENTIFIER ::= {id-hmac 10}
id-hmac-sha512 OBJECT IDENTIFIER ::= {id-hamc 11}
where id-hmac is to be determined.
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2.5 Key Confirmation Methods
<<< To be added. Unilateral, bilateral, etc.>>>
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3 Elliptic Curve Domain Parameters
Elliptic curve domain parameters include the elliptic curve group
used, as well as a particular element of this group, called base
point or generator, and further includes the way the finite field
elements in the elliptic curve points are represented. Elliptic
domain parameters usually include further information such as order
of the base point, a number called the cofactor, a value called
seed which is used to select the curve, and possibly the base
point, verifiably at random. Verifiably random domain parameters
require an auxiliary hash function.
A few changes to elliptic curve domain parameters as originally
specified in ANSI X9.62-2005 and ANSI X9.63-2001 mean that the
corresponding ASN.1 syntax needs the following revisions.
The ASN.1 syntax to represent finite field elements and elliptic
curve points remains unchanged.
The following new ASN.1 type provides the version numbers for
explicitly specifying elliptic curve (EC) domain parameters.
SpecifiedECDomainVersion ::= INTEGER {
ecdpVer1(1), ecdpVer2(2), ecdpVer3(3) }
The ASN.1 type for identifying an elliptic curve remains the same
except the presence of its optional field is governed by the
version number above.
Curve ::= SEQUENCE {
a FieldElement,
b FieldElement,
seed BIT STRING OPTIONAL
}
The ASN.1 type for specifying EC domain parameters has been revised
to include a field to identify the hash function used to generate
the elliptic domain parameters verifiably at random, as follows.
SpecifiedECDomain ::= SEQUENCE {
version SpecifiedECDomainVersion (ecdpVer1 | ecdpVer2 | ecdpVer3),
fieldID FieldID {{FieldTypes}},
curve Curve,
base ECPoint,
order INTEGER,
cofactor INTEGER OPTIONAL,
hash HashAlgorithm OPTIONAL -- New field
}
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A version value of ecdpVer1 is used when either the domain
parameters are not verifiably random or when the curve (not the
base point) is verifiably random (from curve.seed). A version value
of ecdpVer2 is used when the curve and the base point are both
verifiably random (derived from curve.seed). A version value of
ecdpVer3 is used when the base point, but not the curve, is
verifiably random (derived from curve.seed).
If the hash is omitted then, the hash algorithm to be used is
SHA-1.
The object identifiers for NIST recommended curves extend the
object identifiers primeCurve and secgCurve whose values are
primeCurve OBJECT IDENTIFIER ::=
{ iso(1) member-body(2) us(840) 10045 curves(3) prime(1) }
secgCurve OBJECT IDENTIFIER ::=
{ iso(1) identified-organization(3) certicom(132) curve(0) }
The values of the object identifiers for the fifteen NIST
recommended curves are
ansiX9p192r1 OBJECT IDENTIFIER ::= { primeCurve 1 }
ansiX9t163k1 OBJECT IDENTIFIER ::= { secgCurve 1 }
ansiX9t163r2 OBJECT IDENTIFIER ::= { secgCurve 15 }
ansiX9p224r1 OBJECT IDENTIFIER ::= { secgCurve 33 }
ansiX9t233k1 OBJECT IDENTIFIER ::= { secgCurve 26 }
ansiX9t233r1 OBJECT IDENTIFIER ::= { secgCurve 27 }
ansiX9p256r1 OBJECT IDENTIFIER ::= { primeCurve 7 }
ansiX9t283k1 OBJECT IDENTIFIER ::= { secgCurve 16 }
ansiX9t283r1 OBJECT IDENTIFIER ::= { secgCurve 17 }
ansiX9p384r1 OBJECT IDENTIFIER ::= { secgCurve 34 }
ansiX9t409k1 OBJECT IDENTIFIER ::= { secgCurve 36 }
ansiX9t409r1 OBJECT IDENTIFIER ::= { secgCurve 37 }
ansiX9p521r1 OBJECT IDENTIFIER ::= { secgCurve 35 }
ansiX9t571k1 OBJECT IDENTIFIER ::= { secgCurve 38 }
ansiX9t571r1 OBJECT IDENTIFIER ::= { secgCurve 39 }
The following information object class helps to constrain an
field below to identify only a certain EC domain parameters.
ECDOMAIN ::= CLASS { &id OBJECT IDENTIFIER UNIQUE }
WITH SYNTAX { ID &id }
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The following information object set is used to constrain
an AlgorithmIdentifier for identifying EC domain parameters.
ANSINamedECDomains ECDOMAIN ::= {
{ ID ansiX9p192r1 } | { ID ansiX9t163k1 } | { ID ansiX9t163r2 } |
{ ID ansiX9p224r1 } | { ID ansiX9t233k1 } | { ID ansiX9t233r1 } |
{ ID ansiX9p256r1 } | { ID ansiX9t283k1 } | { ID ansiX9t283r1 } |
{ ID ansiX9p384r1 } | { ID ansiX9t409k1 } | { ID ansiX9t409r1 } |
{ ID ansiX9p521r1 } | { ID ansiX9t571k1 } | { ID ansiX9t571r1 } ,
... -- Additional EC domain parameters may be added
}
The ASN.1 type for specifying elliptic curve domain parameters,
whether explicitly, by name, or implicitly, is slightly revised as
follows.
ECDomainParameters ::= CHOICE {
specified SpecifiedECDomain,
named ECDOMAIN.&id({ANSINamedECDomains}),
implicitCA NULL
}
4 ECC Algorithms
ECC algorithms can be identified using algorithm identifiers, in
places such as PKIX certificates (and also in CMS).
In the new syntax here, the parameters field of these algorithm
identifiers sometimes identifies the auxiliary functions.
4.1 Signature Schemes
4.1.1 ECDSA
To identify use of ECDSA with ASN.1, the auxiliary hash function
for computing the message digest is necessary, which shall be
implicit from the object identifier for ECDSA, and possibly as well
as the corresponding public key, or shall be explicitly given in
the parameters field, as detailed below.
The following object identifier serves as the root for further
object identifier in this section.
id-ecSigType OBJECT IDENTIFIER ::=
{ iso(1) member-body(2) us(840) 10045 signatures(4) }
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The following object identifier identifies SHA1 to be used for
message digesting:
ecdsa-with-Sha1 OBJECT IDENTIFIER ::= { id-ecSigType sha1(1) }
The following new object identifier identifies the hash function to
be used for message digesting is the one recommended for the public
key size:
ecdsa-with-Recommended OBJECT IDENTIFIER ::=
{ id-ecSigType recommended(2) }
The recommended hash functions are given in the draft revision of
X9.62, and is determined as follows. Among the hash functions
SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, the recommended one has
the largest bit size that does not require bit truncation during
the signing process. Bit truncation occurs the hash output bit
length is greater than the bit length of n, the order of the base
point G. (Note: even if bit truncation does not occur, modular
reduction can occur.)
The following new object identifier identifies the hash function to
be used for message digesting is the one specified in the
parameters field of the algorithm identifier:
ecdsa-with-Specified OBJECT IDENTIFIER ::= {
id-ecSigType specified(3) }
The following new object identifiers directly identify the hash
function to be used for message digesting.
ecdsa-with-Sha224 OBJECT IDENTIFIER ::=
{ id-ecSigType specified(3) 1 }
ecdsa-with-Sha256 OBJECT IDENTIFIER ::=
{ id-ecSigType specified(3) 2 }
ecdsa-with-Sha384 OBJECT IDENTIFIER ::=
{ id-ecSigType specified(3) 3 }
ecdsa-with-Sha512 OBJECT IDENTIFIER ::=
{ id-ecSigType specified(3) 4 }
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The following information object set helps specify the legal set of
algorithm identifiers for ECDSA.
ECDSAAlgorithmSet ALGORITHM ::= {
{OID ecdsa-with-Sha1} |
{OID ecdsa-with-Sha1 PARMS NULL} |
{OID ecdsa-with-Recommended} |
{OID ecdsa-with-Recommended PARMS NULL} |
{OID ecdsa-with-Specified PARMS HashAlgorithm } |
{OID ecdsa-with-Sha224} |
{OID ecdsa-with-Sha256} |
{OID ecdsa-with-Sha384} |
{OID ecdsa-with-Sha512} ,
... -- More algorithms need to be added
}
The following type is the constrained AlgorithmIdentifier {} that
identifies ECDSA:
ECDSAAlgorithm ::= AlgorithmIdentifier {{ECDSAAlgorithmSet}}
4.2 Key Agreement Schemes
The standard [X9.63] and draft standards [SP 800-56] and
[DSEC1-v1.5] specify some ECC key agreement schemes. The standard
[X9.63] also specifies some ASN.1 syntax, but this will be revised,
as indicated below, in order to accommodate new hash functions such
as SHA-256.
The following object identifiers are used as the root of other
object identifiers that identify cryptographic schemes:
x9-63-scheme OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) ansi-x9-63(63) schemes(0) }
secg-scheme OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) certicom(132) schemes(1) }
4.2.1 1-Pass ECDH
<<< In progress ... >>>
In the 1-Pass Elliptic Curve Diffie-Hellman (ECDH) key agreement
scheme, the initiator sends an ephemeral EC public key to the
responder who has a static EC public key, typically in a
certificate.
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The following object identifiers from ANSI X9.63 identify the use
of 1-Pass ECDH:
dhSinglePass-stdDH-sha1kdf OBJECT IDENTIFIER ::= {x9-63-scheme 2}
dhSinglePass-cofactorDH-sha1kdf OBJECT IDENTIFIER ::=
{x9-63-scheme 3}
dhSinglePass-cofactorDH-recommendedKDF OBJECT IDENTIFIER ::=
{secg-scheme 1}
dhSinglePass-cofactorDH-specifiedKDF OBJECT IDENTIFIER ::=
{secg-scheme 2}
The following information object set helps specify the legal set of
algorithm identifiers for ECDH.
ECDHAlgorithmSet ALGORITHM ::= {
{OID dhSinglePass-stdDH-sha1kdf} |
{OID dhSinglePass-stdDH-sha1kdf PARMS NULL} |
{OID dhSinglePass-cofactorDH-sha1kdf} |
{OID dhSinglePass-cofactorDH-sha1kdf PARMS NULL} |
{OID dhSinglePass-cofactorDH-recommendedKDF} |
{OID dhSinglePass-cofactorDH-specifiedKDF
PARMS KeyDerivationFunction} ,
... -- Future combinations may be added
}
The following type is the constrained AlgorithmIdentifier {} that
legally identifies 1-Pass ECDH:
ECDHAlgorithm ::= AlgorithmIdentifier {{ECDHAlgorithmSet}}
4.2.2 Full and 1-Pass ECMQV
<<< In progress.>>>
In the Full and 1-Pass Elliptic Curve Menezes-Qu-Vanstone (ECMQV)
key agreement schemes, both the initiator and responder have static
EC public keys, typically in certificates, and the initiator sends
an ephemeral EC public key to the responder. In Full ECMQV,
the responder sends the initiator an ephemeral EC public key, but
in 1-Pass ECMQV the sender does not.
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The following object identifiers from ANSI X9.63 identify the
mqvSinglePass-sha1kdf OBJECT IDENTIFIER ::= {x9-63-scheme 16}
mqvSinglePass-recommendedKDF OBJECT IDENTIFIER ::= {secg-scheme 3}
mqvSinglePass-specifiedKDF OBJECT IDENTIFIER ::= {secg-scheme 4}
mqvFull-sha1kdf OBJECT IDENTIFIER ::= {x9-63-scheme 17}
mqvFull-recommendedKDF OBJECT IDENTIFIER ::= {secg-scheme 5}
mqvFull-specifiedKDF OBJECT IDENTIFIER ::= {secg-scheme 6}
The following information object set helps specify the legal set of
algorithm identifiers for ECMQV.
ECMQVAlgorithmSet ALGORITHM ::= {
{OID mqvSinglePass-sha1kdf} |
{OID mqvSinglePass-recommendedKDF} |
{OID mqvSinglePass-specifiedKDF PARMS KeyDerivationFunction} |
{OID mqvFull-sha1kdf} |
{OID mqvFull-recommendedKDF} |
{OID mqvFull-specifiedKDF PARMS KeyDerivationFunction} ,
... -- Future combinations may be added
}
The following type is the constrained AlgorithmIdentifier {} that
legally identifies 1-Pass and Full ECMQV:
ECMQVAlgorithm ::= AlgorithmIdentifier {{ECMQVAlgorithmSet}}
i
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4.3 ECC Algorithm Set
The following information object set helps specify a legal set of
ECC algorithms.
ECCAlgorithmSet ALGORITHM ::= {
ECDSAAlgorithmSet |
ECDHAlgorithmSet |
ECMQVAlgorithmSet ,
... -- Future combinations may be added
}
The following type is the constrained AlgorithmIdentifier {} that
legally identifies an ECC algorithm:
ECCAlgorithm ::= AlgorithmIdentifier {{ECCAlgorithmSet}}
The following type permits a sequence of ECC algorithm identifier
to given.
ECCAlgorithms ::= SEQUENCE OF ECCAlgorithm
The order of the sequence SHOULD indicate an order of preference
for which algorithm to used, where appropriate.
5 ECC Keys
Keys in ECC generally need to be associated with additional
information such as domain parameters as well as, possibly,
restrictions or preferences on algorithms that key can be used
with.
5.1 Public Keys
Public keys are generally contained in certificates or stored in
trusted memory, often in self-signed certificated format.
Certificates are conveyed between parties or accessed from
directories.
For certificates containing elliptic curve subject public keys, or
certificates signed with elliptic curve issuer public keys using
ECDSA, it is often necessary to identify the particular ECC
algorithms and elliptic curve domain parameters that are used.
Certificates with ECC subject public keys can either restrict or
not restrict the set of ECC algorithms with which they are used.
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Unrestricted public keys are identified by the following OID:
id-ecPublicKey OBJECT IDENTIFIER ::= {
iso(1) member-body(2) us(840) 10045 keyType(2) unrestricted(1)
}
This OID is used in an algorithm identifier as follows:
ecPublicKeyType ALGORITHM ::= {
OID id-ecPublicKey PARMS ECDomainParameters
}
The following new syntax identifies ECC subject keys restricted to
a certain subset of ECC algorithms. Firstly, the following OID is
used:
id-ecPublicKeyRestricted OBJECT IDENTIFIER ::= {
iso(1) member-body(2) us(840) 10045 keyType(2) restricted(2)
}
The following new syntax permits both elliptic curve domain
parameters and a sequence of algorithm restrictions to be
associated with an ECC public key:
ECPKRestrictions ::= SEQUENCE {
ecDomain ECDomainParameters,
eccAlgorithms ECCAlgorithms
}
The new OID and new type are used in an algorithm identifier as
follows:
ecPublicKeyTypeRestricted ALGORITHM ::= {
OID id-ecPublicKeyRestricted PARMS ECPKRestrictions
}
The following information object set ECPKAlgorithmSet specifies the
legal set of algorithm identifiers to identify an ECC public key:
ECPKAlgorithmSet ::= {
ecPublicKeyType | ecPublicKeyTypeRestricted ,
... -- Further ECC public key types might be added
}
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The following type uses the set above to constrain a algorithm
identifier accordingly:
ECPKAlgorithm ::= AlgorithmIdentifier {ECPKAlgorithmSet}
In a PKIX certificate with an ECC subject public key, the
SubjectPublicKeyInfo type shall use the following syntax:
SubjectPublicKeyInfo ::= SEQUENCE {
algorithm ECPKAlgorithm,
subjectPublicKey BIT STRING
}
The elliptic curve public key (a value of type ECPoint which is an
OCTET STRING) is mapped to a subjectPublicKey (a value of type BIT
STRING) as follows: the most significant bit of the OCTET STRING
value becomes the most significant bit of the BIT STRING value, and
so on; the least significant bit of the OCTET STRING becomes the
least significant bit of the BIT STRING.
5.2 Private Keys
<<< To be added. Perhaps unnecessary for PKIX. >>>
6 ASN.1 Module(s)
<<< To be added, once ASN.1 decided. >>>
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7 References
[FIPS 180-2] U.S. Department of Commerce/National Institute of
Standards and Technology. Secure Hash Standard (SHS), FIPS
PUB 180-2, Change Notice 1,
http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdf
[FIPS 186-2] U.S. Department of Commerce/National Institute of
Standards and Technology. Digital Signature Standard (DSS), FIPS
PUB 186-2, January 2000.
http://csrc.nist.gov/publications/fips/fips186-2/fips186-2-change1.pdf
[RFC 3279] W. Polk, R. Housley and L. Bassham. Algorithms and
Identifiers for the Internet X.509 Public Key Infrastructure
Certificate and Certificate Revocation List (CRL) Profile, April
2002.
[RFC 3278] S. Blake-Wilson, D. Brown, and P. Lambert. Use of ECC
Algorithms in CMS, April 2002.
[SEC1v1] Standards for Efficient Cryptography Group. SEC 1 - Elliptic
Curve Cryptography, Version 1.0. September,
2000. (http://www.secg.org)
[DSEC1-v1.5] Standards for Efficient Cryptography Group. SEC 1 -
Elliptic Curve Cryptography, Draft Version 1.5. February,
2005. (http://www.secg.org)
[SEC2] Standards for Efficient Cryptography Group. SEC 2 -
Recommended Elliptic Curve Domain Parameters, Version
1.0. September, 2000. (http://www.secg.org)
[SP 800-56] E. Barker, D. Johnson, and M. SmidNIST Special
Publication 800-56A, Recommendation for Pair-Wise Key
Establishment Schemes Using Discrete Logarithm
Cryptography. March, 2006.
[X9.62] American National Standard for Financial Services. ANSI
X9.62-2005, Public Key Cryptography for the Financial Services
Industry: The Elliptic Curve Digital Signature Algorithm.
November, 2005.
[X9.63] American National Standard for Financial Services. ANSI
X9.63-2001, Public Key Cryptography for the Financial Services
Industry: Key Agreement and Key Transport using Elliptic Curve
Cryptography. November, 2001.
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8 Security Considerations
<<< To be added later. >>>
9 Acknowledgments
To be added later.
10 Authors' Addresses
Authors:
Daniel R. L. Brown
Certicom Corp.
dbrown@certicom.com
11 Full Copyright Statement
Copyright (C) The Internet Society (2006).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on
an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT
THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR
ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE.
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