AIVS: Agentic Integrity Verification Standard
draft-stone-aivs-00

Individual Submission                                           B. Stone
Internet-Draft                                              SwarmSync.AI
Intended status: Informational                                March 2026
Expires: 18 September 2026

             AIVS: Agentic Integrity Verification Standard
                          draft-stone-aivs-00

Abstract

   This document specifies the Agentic Integrity Verification Standard
   (AIVS), a portable, self-verifiable archive format for cryptographic
   proof of AI agent sessions.  An AIVS proof bundle is a gzip-
   compressed tar archive containing a SHA-256 hash-chained audit log,
   an Ed25519 digital signature over the chain, a machine-readable
   manifest, and an embedded verification script that requires only the
   Python 3 standard library to execute.  AIVS also defines AIVS-Micro:
   a minimal six-field attestation (~200 bytes) for continuous
   monitoring and API contexts where a full session bundle is not
   required.  AIVS enables any party to independently verify that every
   action in an agent session is accounted for and unmodified, that no
   actions have been inserted, deleted, or reordered, and that the
   session was produced by a specific cryptographic identity — entirely
   offline, without installing any software beyond Python 3.

Status of This Memo

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   This Internet-Draft will expire on 2 September 2026.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  1.  Introduction  . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  1.1 Problem Statement . . . . . . . . . . . . . . . . . .   3
     1.2.  1.2 Design Goals  . . . . . . . . . . . . . . . . . . . .   3
     1.3.  1.3 Relationship to Existing Standards  . . . . . . . . .   4
     1.4.  1.4 Terminology . . . . . . . . . . . . . . . . . . . . .   4
   2.  2.  Hash Chain Specification  . . . . . . . . . . . . . . . .   4
     2.1.  2.1 Row Hash Computation  . . . . . . . . . . . . . . . .   4
     2.2.  2.2 Field Definitions . . . . . . . . . . . . . . . . . .   5
     2.3.  2.3 Chain Integrity Property  . . . . . . . . . . . . . .   5
     2.4.  2.4 Chain Hash Computation  . . . . . . . . . . . . . . .   5
   3.  3.  Audit Row Schema  . . . . . . . . . . . . . . . . . . . .   6
     3.1.  3.1 Row Format  . . . . . . . . . . . . . . . . . . . . .   6
     3.2.  3.2 Field Specifications  . . . . . . . . . . . . . . . .   6
     3.3.  3.3 Sensitive Input Redaction . . . . . . . . . . . . . .   6
     3.4.  3.4 Output Truncation . . . . . . . . . . . . . . . . . .   7
   4.  4.  Ed25519 Signature . . . . . . . . . . . . . . . . . . . .   7
     4.1.  4.1 Signing . . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  4.2 Identity Key Properties . . . . . . . . . . . . . . .   7
     4.3.  4.3 Signature File Format (session_sig.txt) . . . . . . .   7
     4.4.  4.4 Signature is Optional . . . . . . . . . . . . . . . .   7
   5.  5.  AIVS Full Bundle Format . . . . . . . . . . . . . . . . .   7
     5.1.  5.1 Archive Structure . . . . . . . . . . . . . . . . . .   7
     5.2.  5.2 manifest.json . . . . . . . . . . . . . . . . . . . .   8
     5.3.  5.3 verify.py Requirements  . . . . . . . . . . . . . . .   8
     5.4.  5.4 Bundle Chaining (Optional)  . . . . . . . . . . . . .   8
   6.  6.  AIVS-Micro  . . . . . . . . . . . . . . . . . . . . . . .   8
     6.1.  6.1 Purpose . . . . . . . . . . . . . . . . . . . . . . .   8
     6.2.  6.2 Micro Proof Format  . . . . . . . . . . . . . . . . .   8
     6.3.  6.3 Canonical Payload for Signing . . . . . . . . . . . .   9
     6.4.  6.4 Micro Proof Verification  . . . . . . . . . . . . . .   9
   7.  7.  Verification Algorithm  . . . . . . . . . . . . . . . . .   9
     7.1.  7.1 Hash Chain Verification (REQUIRED)  . . . . . . . . .   9
     7.2.  7.2 Ed25519 Signature Verification (OPTIONAL) . . . . . .  10
     7.3.  7.3 Exit Codes  . . . . . . . . . . . . . . . . . . . . .  10
   8.  8.  Security Considerations . . . . . . . . . . . . . . . . .  10
     8.1.  8.1 What AIVS Proves  . . . . . . . . . . . . . . . . . .  10
     8.2.  8.2 What AIVS Does NOT Prove  . . . . . . . . . . . . . .  10

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     8.3.  8.3 Threat Model  . . . . . . . . . . . . . . . . . . . .  11
   9.  9.  IANA Considerations . . . . . . . . . . . . . . . . . . .  11
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     10.2.  Informative References . . . . . . . . . . . . . . . . .  11
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  12

1.  1.  Introduction

1.1.  1.1 Problem Statement

   AI agents increasingly perform consequential actions on behalf of
   humans: navigating websites, filling forms, executing JavaScript,
   extracting data, and making purchases.  Existing observability
   platforms (OpenTelemetry, LangSmith, Langfuse) log these actions but
   provide no cryptographic guarantees that the logs are complete,
   unmodified, or authentic.

   Regulatory frameworks mandate audit trails but do not prescribe
   formats:

   EU AI Act Article 19 requires automatically generated logs for high-
   risk AI systems but specifies no format.

   ISO/IEC 42001:2023 Annex A.6.2.8 requires event logging but defines
   no data structure.

   NIST AI RMF requires documentation and audit trails but deliberately
   avoids prescribing formats.

   This creates a gap: organizations that must prove what their AI
   agents did have no standard way to produce, exchange, or verify that
   proof.

1.2.  1.2 Design Goals

| Goal              | Rationale                                              |
|-------------------|--------------------------------------------------------|
| Self-verifiable   | Bundles verifiable without contacting any server,      |
|                   | blockchain, or authority.                              |
| Portable          | A single file that can be emailed, stored, or          |
|                   | submitted to any system.                               |
| Tamper-evident    | Modifying any action in the log must be detectable.    |
| Zero dependencies | Verification requires only Python 3 standard library.  |
| Session-level     | Covers an entire session (sequence of actions).        |
| Lightweight       | AIVS-Micro provides ~200-byte attestation for          |
| profile           | high-frequency monitoring.                             |
| Domain-agnostic   | Applicable to any AI agent performing any action.      |

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1.3.  1.3 Relationship to Existing Standards

| Standard              | Scope                        | AIVS Relationship              |
|-----------------------|------------------------------|--------------------------------|
| W3C VC 2.0            | Identity claims              | AIVS bundles may be wrapped    |
|                       |                              | as VC credentialSubject        |
| IETF SCITT            | Supply chain transparency    | AIVS bundles may be registered |
|                       |                              | as SCITT signed statements     |
| C2PA v2.2             | Media asset provenance       | AIVS applies the same          |
|                       |                              | manifest-chain concept to      |
|                       |                              | agent actions                  |
| Certificate           | Append-only Merkle logs      | AIVS hash chain is a           |
| Transparency RFC 6962 |                              | simplified linear variant      |
| EU AI Act Art. 19     | Audit log requirements       | AIVS is a concrete format      |
|                       |                              | satisfying Article 19          |

1.4.  1.4 Terminology

| Term               | Definition                                              |
|--------------------|--------------------------------------------------------|
| Session            | A bounded sequence of actions performed by a single    |
|                    | AI agent instance, identified by a session_id.         |
| Action             | A single operation performed by the agent (e.g.,       |
|                    | navigate to URL, click element, execute JavaScript).   |
| Audit Row          | A JSON object recording one action with its inputs,    |
|                    | outputs, timestamp, cost, and hash chain fields.       |
| Hash Chain         | A sequence of audit rows where each row's hash         |
|                    | depends on the previous row's hash.                    |
| Chain Hash         | A single SHA-256 hash computed over all row hashes,    |
|                    | serving as a fingerprint of the entire session.        |
| Proof Bundle       | A .tar.gz archive containing the audit log, signature, |
|                    | manifest, public key, and verifier script.             |
| AIVS-Micro         | A minimal 6-field JSON proof (~200 bytes) for a        |
|                    | single-URL scan attestation.                           |
| Identity Key       | An Ed25519 keypair used to sign the chain hash.        |

2.  2.  Hash Chain Specification

2.1.  2.1 Row Hash Computation

   Each audit row is identified by a deterministic SHA-256 hash.  The
   hash input is a colon-separated string of exactly seven fields in
   this order:

row_hash = SHA-256(
    "{row_id}:{session_id}:{action_type}:{tool_name}:{cost_cents}:{timestamp}:{prev_hash}"
)

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   The hash is represented as a lowercase hexadecimal string (64
   characters).

2.2.  2.2 Field Definitions

| Field        | Type    | Description                                     |
|--------------|---------|-------------------------------------------------|
| row_id       | Integer | Monotonically increasing row identifier          |
|              |         | (1-indexed).                                    |
| session_id   | String  | Unique identifier for the session.              |
| action_type  | String  | Classification of the action.                   |
|              |         | Default: "tool_call".                           |
| tool_name    | String  | Namespaced tool identifier                      |
|              |         | (e.g., "browser.navigate").                     |
| cost_cents   | Integer | Cost of the action in cents. 0 for free         |
|              |         | actions.                                        |
| timestamp    | Float   | Unix timestamp with fractional seconds.         |
| prev_hash    | String  | row_hash of the immediately preceding row.      |
|              |         | Empty string for the first row.                 |

2.3.  2.3 Chain Integrity Property

   For a chain of N rows, modifying any field of row K invalidates
   row_hash[K], which invalidates prev_hash[K+1], and so on through
   row_hash[N].  This means:

   Insertion of a row is detectable (changes all subsequent row_id
   values and hashes).

   Deletion of a row is detectable (breaks the prev_hash link).

   Reordering of rows is detectable (changes prev_hash linkage).

   Modification of any field is detectable (changes the affected row's
   hash and all subsequent hashes).

2.4.  2.4 Chain Hash Computation

  If rows is empty:
      chain_hash = SHA-256(b"empty")
  Else:
      combined = concatenate(row_hash[1], row_hash[2], ..., row_hash[N])
      chain_hash = SHA-256(combined.encode("utf-8"))

   The chain hash is represented as a lowercase hexadecimal string (64
   characters).

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3.  3.  Audit Row Schema

3.1.  3.1 Row Format

   {
     "id":           1,
     "session_id":   "sess-abc123",
     "action_type":  "tool_call",
     "tool_name":    "browser.navigate",
     "inputs_json":  "{\"url\": \"https://example.com\"}",
     "outputs_json": "{\"title\": \"Example Domain\"}",
     "cost_cents":   0,
     "error":        "",
     "timestamp":    1710252645.123456,
     "prev_hash":    "",
     "row_hash":     "a1b2c3d4e5f6..."
   }

3.2.  3.2 Field Specifications

| Field        | Type    | Required | Description                        |
|--------------|---------|----------|------------------------------------|
| id           | Integer | Yes      | Row identifier, 1-indexed,         |
|              |         |          | monotonically increasing.          |
| session_id   | String  | Yes      | Session identifier.                |
| action_type  | String  | Yes      | Action classification.             |
| tool_name    | String  | Yes      | Namespaced tool identifier.        |
| inputs_json  | String  | Yes      | JSON-encoded action inputs.        |
|              |         |          | Sensitive keys MUST be redacted.   |
| outputs_json | String  | Yes      | JSON-encoded action outputs.       |
|              |         |          | MAY be truncated.                  |
| cost_cents   | Integer | Yes      | Action cost in cents.              |
| error        | String  | Yes      | Error message; empty if success.   |
| timestamp    | Float   | Yes      | Unix timestamp, fractional secs.   |
| prev_hash    | String  | Yes      | Previous row's row_hash.           |
| row_hash     | String  | Yes      | This row's computed SHA-256 hash.  |

3.3.  3.3 Sensitive Input Redaction

   Before computing the row hash, implementations MUST redact values for
   input keys matching any of the following case-insensitive substrings:

   password, token, api_key, secret, key, authorization,
   bearer, credential, passwd, passphrase

   Redacted values MUST be replaced with the string "[REDACTED]".

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3.4.  3.4 Output Truncation

   Implementations MAY truncate outputs_json to a maximum length.  The
   reference implementation truncates to 2000 characters.  Truncation
   does not affect the hash chain because outputs_json is not included
   in the row hash computation.

4.  4.  Ed25519 Signature

4.1.  4.1 Signing

 signature_bytes = Ed25519_Sign(private_key, chain_hash.encode("utf-8"))
 signature_b64   = Base64_Encode(signature_bytes)

4.2.  4.2 Identity Key Properties

   | Property            | Value                                     |
   |---------------------|-------------------------------------------|
   | Algorithm           | Ed25519 (RFC 8032)                        |
   | Private key size    | 32 bytes                                  |
   | Public key size     | 32 bytes                                  |
   | Storage format      | Raw bytes (not PEM)                       |
   | Public key repr.    | 64-character lowercase hexadecimal string |
   | File permissions    | 0600 (owner read/write only)              |

4.3.  4.3 Signature File Format (session_sig.txt)

   chain_hash:{64-char-hex-chain-hash}
   signature:{base64-encoded-signature}

4.4.  4.4 Signature is Optional

   Implementations MAY produce bundles without Ed25519 signatures.  The
   hash chain provides tamper-evidence independent of the signature.
   The signature adds identity binding (proof of who produced the
   bundle).

5.  5.  AIVS Full Bundle Format

5.1.  5.1 Archive Structure

   aivs_proof_{session_prefix}_{unix_timestamp}.tar.gz
   └── session_proof/
       ├── audit_log.jsonl       # Hash-chained action log
       ├── manifest.json         # Bundle metadata
       ├── session_sig.txt       # Ed25519 signature
       ├── public_key.pem        # Signer's public key
       └── verify.py             # Self-contained verifier (stdlib only)

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5.2.  5.2 manifest.json

   {
     "session_id":    "sess-abc123",
     "exported_at":   "2026-03-14T15:30:45Z",
     "action_count":  42,
     "chain_hash":    "a1b2c3d4...",
     "aivs_version":  "1.0",
     "generator":     "ExampleAgent",
     "generator_url": "https://github.com/example/agent"
   }

5.3.  5.3 verify.py Requirements

   The embedded verifier script MUST:

   Verify the hash chain using only Python 3 standard library (hashlib,
   json, sys, pathlib).

   Exit with code 0 on successful verification.

   Exit with code 1 if the hash chain is broken or the signature is
   invalid.

   Print human-readable verification results to stdout.

   The embedded verifier MAY verify the Ed25519 signature if the
   cryptography library is available.

5.4.  5.4 Bundle Chaining (Optional)

   When a session produces multiple sequential bundles, each bundle MAY
   reference its predecessor via previous_bundle_hash.txt, containing
   the SHA-256 hex digest of the prior .tar.gz file.  This forms a scan
   chain: a tamper-evident sequence of bundles where each bundle
   cryptographically references its predecessor.

6.  6.  AIVS-Micro

6.1.  6.1 Purpose

   AIVS-Micro is a minimal single-URL scan attestation (~200 bytes)
   designed for use cases where a full session bundle is impractical:
   continuous monitoring, embedded score widgets, API responses, and DNS
   TXT record verification.

6.2.  6.2 Micro Proof Format

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   {
     "url":                  "https://example.com",
     "dom_hash":             "sha256:a1b2c3d4e5f6...",
     "timestamp":            "2026-03-14T10:22:01.000000000Z",
     "signature":            "ed25519:BASE64_ENCODED_SIGNATURE",
     "scanner_version_hash": "sha256:def456...",
     "scan_origin":          "local"
   }

6.3.  6.3 Canonical Payload for Signing

   {url}|{dom_hash}|{timestamp}|{scanner_version_hash}|{scan_origin}

6.4.  6.4 Micro Proof Verification

1. Reconstruct canonical payload:
   payload = "{url}|{dom_hash}|{timestamp}|{scanner_version_hash}|{scan_origin}"

2. Decode signature:
   sig_b64 = micro_proof["signature"].removeprefix("ed25519:")
   sig_bytes = Base64_Decode(sig_b64)

3. Verify:
   Ed25519_Verify(public_key, sig_bytes, payload.encode("utf-8"))

4. If verification succeeds: PASS
5. If verification fails:   FAIL
6. If signature == "unsigned": SKIP

7.  7.  Verification Algorithm

7.1.  7.1 Hash Chain Verification (REQUIRED)

  Input:  audit_log.jsonl
  Output: PASS or FAIL with row number

  prev_hash = ""
  for each row in audit_log.jsonl (ordered by id):
      expected = SHA-256(
          "{row.id}:{row.session_id}:{row.action_type}:"
          "{row.tool_name}:{row.cost_cents}:{row.timestamp}:{prev_hash}"
      )
      if row.row_hash != expected:
          FAIL at row.id
      prev_hash = row.row_hash

  PASS: all N rows verified

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7.2.  7.2 Ed25519 Signature Verification (OPTIONAL)

   Input:  session_sig.txt, public_key.pem
   Output: PASS, FAIL, or SKIP

   1. Parse chain_hash and signature from session_sig.txt
   2. Parse public key hex from public_key.pem
   3. If no signing key configured: SKIP
   4. Reconstruct Ed25519PublicKey from raw bytes
   5. Verify: Ed25519_Verify(public_key, signature,
              chain_hash.encode("utf-8"))
   6. If verification succeeds: PASS
   7. If verification fails:    FAIL (exit 1)
   8. If cryptography library unavailable: SKIP with notice

7.3.  7.3 Exit Codes

| Code | Meaning                                                       |
|------|---------------------------------------------------------------|
| 0    | Hash chain verified. Signature verified (if available).       |
| 1    | Hash chain broken OR signature invalid.                       |

8.  8.  Security Considerations

8.1.  8.1 What AIVS Proves

   Integrity: The sequence of actions has not been modified since the
   bundle was created.

   Completeness: No actions have been inserted or deleted from the
   chain.

   Ordering: Actions occurred in the recorded sequence.

   Identity (with signature): The bundle was produced by the holder of a
   specific Ed25519 private key.

8.2.  8.2 What AIVS Does NOT Prove

   Truthfulness: AIVS does not prove that the recorded inputs/outputs
   actually occurred.  A malicious agent could fabricate actions and
   produce a valid chain.

   Timeliness: Timestamps are self-reported.  Implementations requiring
   trusted timestamps SHOULD layer RFC 3161 on top.

   Key authenticity: AIVS does not include a PKI or certificate chain.
   The public key in the bundle is self-asserted.

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8.3.  8.3 Threat Model

| Threat                            | Mitigated By                          |
|-----------------------------------|---------------------------------------|
| Post-hoc modification of log      | Hash chain (Section 2)                |
| Deletion of actions               | Sequential prev_hash chaining         |
| Insertion of actions              | Sequential row_id + prev_hash         |
| Reordering of actions             | prev_hash depends on previous hash    |
| Impersonation of agent identity   | Ed25519 signature (Section 4)         |
| Exposure of sensitive inputs      | Mandatory redaction (Section 3.3)     |
| Replay of old proof bundle        | session_id + timestamp uniqueness     |

9.  9.  IANA Considerations

   This document defines no new IANA registries.  The following existing
   standards are referenced: SHA-256 (FIPS 180-4), Ed25519 (RFC 8032),
   JSON (RFC 8259), gzip (RFC 1952).

10.  References

10.1.  Normative References

   [RFC1952]  Deutsch, P., "GZIP file format specification version 4.3",
              RFC 1952, May 1996,
              <https://www.rfc-editor.org/rfc/rfc1952>.

   [RFC8032]  Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital
              Signature Algorithm (EdDSA)", RFC 8032, January 2017,
              <https://www.rfc-editor.org/rfc/rfc8032>.

   [RFC8259]  Bray, T., "The JavaScript Object Notation (JSON) Data
              Interchange Format", RFC 8259, December 2017,
              <https://www.rfc-editor.org/rfc/rfc8259>.

10.2.  Informative References

   [I-D.rosenberg-oauth-aauth]
              Rosenberg, J., "OAuth for Agentic AI Authorization", Work
              in Progress, Internet-Draft, draft-rosenberg-oauth-aauth-
              01, 2026, <https://datatracker.ietf.org/doc/html/draft-
              rosenberg-oauth-aauth-01>.

   [I-D.stone-vcap]
              Stone, B., "VCAP: Verified Commerce for Agent Protocols",
              Work in Progress, Internet-Draft, draft-stone-vcap-00,
              2026, <https://datatracker.ietf.org/doc/html/draft-stone-
              vcap-00>.

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   [RFC3161]  Adams, C., "Internet X.509 Public Key Infrastructure Time-
              Stamp Protocol (TSP)", RFC 3161, August 2001,
              <https://www.rfc-editor.org/rfc/rfc3161>.

   [RFC6962]  Laurie, B., Langley, A., and E. Kasper, "Certificate
              Transparency", RFC 6962, June 2013,
              <https://www.rfc-editor.org/rfc/rfc6962>.

Author's Address

   Ben Stone
   SwarmSync.AI
   Email: benstone@swarmsync.ai

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