ZPK1 - Protocol

ZEUS PROOF KERNEL v1 - Canonical Proof Formatting

Status: Stable Version Prefix: ZPK1 Introduced In: zeus-time 0.3.0

Example

ZPK1|canon=json_sorted_compact|algo=blake3|tag=invoice:v1|digest=91ab4e8f4c2b7f...

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Purpose

ZPK1 defines a deterministic, portable, human-readable packaging format for pre-hashed payloads intended for temporal attestation by ZEUS.

ZPK1 exists to:

• Eliminate JSON formatting ambiguity\

• Prevent whitespace and encoding drift\

• Avoid raw payload transmission\

• Ensure strict cross-language reproducibility\

• Bind canonicalization and algorithm choice into the attested object

ZPK1 contains no raw payload data. It contains only metadata and a digest.

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Canonical String Format

ZPK1 is a UTF-8 encoded, pipe-delimited string with strict field ordering.

Without tag

ZPK1|canon=<mode>|algo=<algorithm>|digest=<hex>

With optional tag

ZPK1|canon=<mode>|algo=<algorithm>|tag=<label>|digest=<hex>

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Structural Rules

The following rules are mandatory:

1. The string MUST begin with the literal prefix ZPK1

2. Fields MUST appear in exact order

3. No additional fields are permitted

4. No whitespace is permitted anywhere in the string

5. The delimiter between fields is |

6. The delimiter between key and value is =

7. Field names are lowercase and case-sensitive

8. The string MUST be valid UTF-8

9. Empty fields are not allowed

ZPK1 is intentionally strict. No auto-correction is permitted.

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Required Fields

1

canon

Specifies the canonicalization method applied before hashing.

Allowed values:

• utf8_exact

• json_sorted_compact

• bytes_b64

Each canonicalization mode MUST be deterministic.

2

algo

Specifies the hashing algorithm used to generate the digest.

Allowed values:

• blake3

• sha256

The algorithm MUST be explicitly declared. There are no implicit defaults.

3

digest

Lowercase hexadecimal representation of the hash output.

Rules:

• Must contain only [0-9a-f]

• Uppercase hex is invalid

• Must be exactly 64 characters long

• For blake3, output is fixed at 32 bytes (64 hex chars)

• Extendable output mode (XOF) is not permitted

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Optional Field

tag

Optional short descriptor.

Rules:

• Must not contain |

• Must not contain =

• Must not be empty

• UTF-8 encoded

• Recommended maximum length: 64 characters

• Must not contain sensitive data

• Does not affect digest calculation

If present, tag MUST appear between algo and digest.

Correct ordering:

ZPK1|canon=...|algo=...|tag=...|digest=...

If omitted, the field must be removed entirely.

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Determinism Requirements

Given identical input and canonicalization method:

• The resulting digest MUST be byte-identical

• The resulting ZPK1 string MUST be byte-identical

• Tag MUST NOT influence digest

• Repacking identical data MUST produce identical ZPK1 output

ZPK1 is deterministic by design.

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Validation Requirements

Any compliant validator MUST reject:

• Incorrect prefix

• Incorrect field order

• Missing required fields

• Extra fields

• Unsupported canon values

• Unsupported algo values

• Uppercase hexadecimal

• Incorrect digest length

• Whitespace anywhere

• Empty or malformed tag

• Malformed key/value structure

Validation must be strict. Silent normalization is not allowed.

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Attestation Behavior (ZEUS Verify)

When a ZPK1 string is submitted to ZEUS Verify:

• The entire string MUST be stamped exactly as received

• Receipt binding is to the full packed string, not just the digest

• Verification requires exact string match

ZPK1 enables privacy-preserving timestamping without transmitting raw payload data.

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Versioning Policy

• ZPK1 is the protocol version marker

• Structural breaking changes require a new prefix, e.g. ZPK2

• Backward compatibility between major ZPK versions is not guaranteed

• ZPK1 behavior is fixed once published

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Design Principles

ZPK1 is:

• Minimal\

• Deterministic\

• Strict\

• Human-readable\

• Machine-parseable\

• Privacy-preserving\

• Non-extensible within a version

ZPK1 intentionally avoids hidden defaults and ambiguous parsing.