Bounded Authority Protocol v2 Wire Profile

Document revision: rev 1 (2026-09-13). Status: normative. Contract-major 2, suite BAP2-Ed25519-SHA256. This profile is activated by ADR 0030 under the successor-major charter; the selector mechanism it activates is specified by ADR 0028.

The v2 profile is a complete closed wire profile parallel to the frozen v1 profile (bap-v1.md). Conformance language, the abstract data model, JSON decoding and canonical serialization, base64url, protected headers, claims, URI normalization, signing and digest inputs, the consumption chain and anchored export, the public verification contract, hard maxima, the untrusted key locator, typ values, and security/privacy considerations are INCORPORATED FROM v1 BY REFERENCE with the substitutions of §2 — every such section is normative for v2 exactly as for v1, with the named constants replaced. No section of the v1 profile is optional, open, or best-effort in v2. Sections 3–6 state the v2-specific normative rules in full, including the selector algebra with the two range kinds.

1. Suite identity and major detection {#suite}

The v2 profile's suite is BAP2-Ed25519-SHA256: EdDSA over Ed25519, SHA-256 digests, RFC 8785 JCS canonical bytes, and the BAP2-* domain separators — the same closed posture and algorithms as BAP1-Ed25519-SHA256 under the major-bound naming scheme BAP<contract-major>-<signature>-<digest>.

Every v2 artifact declares its contract-major mechanically: the payload v claim is exactly integer 2, the protected typ header carries the same closed values as v1, and the domain separators are version-bound. A conforming v2 verifier detects the profile of any artifact from its bytes alone.

Cross-major rules (REQ2-CORE-cross-major-reject): a v2 verifier rejects every artifact whose payload v is not exactly 2 — including all v1 artifacts — with the single closed error; the v1 profile rejects all v2 bytes symmetrically. There is no cross-major fallback, downgrade, or best-effort parsing in either direction. A holder presents artifacts of one major end-to-end: a v2 proof MUST pair with a v2 grant (REQ2-EVO-proof-major-equals-grant); mixed-major credentials are invalid by construction (REQ2-EVO-mixed-major-invalid).

2. Substitutions incorporated from v1 {#substitutions}

For every v1 section not restated below, the normative v2 text is the v1 text with exactly these substitutions (REQ2-CORE-v1-incorporation):

All bounds, key widths, claim member sets, header member sets, typ values (ba+cap, dpop+jwt, ba+chain-anchor, ba+key-transition), and requirement cross-references to the shared verification semantics are unchanged. The local-loopback application proof profile (bap-application-proof/local-loopback-http/v1) is bound to contract-major 1; it pairs with no v2 grant, and the v2 façade exposes no loopback functions.

3. Hard maxima {#maxima}

The v2 profile inherits every v1 bound unchanged (REQ2-BOUNDS-inherited): the ADR 0028 §4 review found that a range comparison consumes two decoder-bounded numbers and produces a boolean — it derives no new magnitude, so no new Bounds member is required. The complete bound set is the v1 §17 table, including the selector maxima restated in §5 below.

4. Selector algebra {#selectors}

Selectors are closed ordered objects with exactly one of three recognized member sets: {kind}, {kind,path,value}, or {kind,path,values} … the member-set discipline is v1 §12 verbatim (REQ2-SELECTOR-closed-set), with the kind selecting among FIVE kinds:

Range-kind rules (REQ2-SELECTOR-range-same-tag, REQ2-SELECTOR-range-inclusive, REQ2-SELECTOR-range-numeric):

• Both operands — the traversed value at path and the bound in value — MUST carry the same numeric tag: both integer-tagged or both float-tagged. A cross-tag pair does not match; it fails closed exactly as equals never collapses tags. This extends the v1 no-tag-collapse invariant from identity to ordering.
• Comparison is by numeric value on the closed numeric domain the bounded decoder admits (integers and floats within ±9007199254740991). Under IEEE 754 numeric comparison −0.0 = 0.0; because RFC 8785 serializes both as 0 (the ECMAScript Number::toString rule), signed zero distinguishes no authority in either the comparison or the canonical bytes, and a zero-valued operand re-derives from the wire with the integer tag (REQ2-SELECTOR-range-signed-zero).
• By the same serialization rule, an integral-valued float bound (e.g. 10.0) canonicalizes to 10 and decodes back integer-tagged: float-tagged bounds are wire-distinguishable only when non-integral. Issuers therefore express integer bounds as integers; the tag carries the operand domain, not a unit.
• Non-numeric operands fail closed: a string, boolean, null, array, or object value at the path never satisfies a range selector, and a non-numeric value member makes the whole grant {:error, :invalid} at decode (REQ2-SELECTOR-range-numeric). A missing path member fails closed exactly as for equals/one_of (REQ2-SELECTOR-range-path-required).
• An interval is the CONJUNCTIVE COMPOSITION of two one-sided selectors on the same path ({gte, path, lo} + {lte, path, hi}), exactly as any other conjunction composes. There is no compound range kind. Crossed endpoints (lo > hi) are not a special error: the conjunction is unsatisfiable and never matches (REQ2-SELECTOR-range-interval).
• Strict kinds (lt, gt) do not exist and are excluded permanently (REQ2-SELECTOR-no-strict-kinds): on integers a strict bound is derivable (amount < 100 ≡ amount ≤ 99), and no authority-named mandate requires a strict float bound.

Path discipline is identical to equals/one_of (REQ2-SELECTOR-path-shape): 1–32 object-member names, 1–128 UTF-8 bytes each, object traversal only, never array indexing. An operation carries 1–64 selectors unchanged (REQ2-SELECTOR-count). Selector matching is verdict-internal: the standalone grant verification checks signature, issuer, audience, and times only, and never evaluates selectors (REQ2-SELECTOR-verdict-internal). Facts are unchanged — a range bound is a payload magnitude read from the decoded grant of the same verified bytes, never a fact, and no selector grants business authorization (REQ2-SELECTOR-not-authorization).

Issuer guidance (informative). A range selector compares numbers only. When an argument's meaning depends on a unit carried in another member (a currency code, a scale, or a decimal exponent), the issuer pairs each range selector with an equals selector on that unit member; without that conjunct, a bound of 25000 authorizes 25000 in any unit. Because paths never index arrays, a bound cannot reach each element of a list; issuers shape arguments so that every bounded value is an object member.

Attenuation (when a successor major activates delegation) composes conjunctively over selector tuples and never inspects kind; the new kinds are new tuple inhabitants of the existing algebra, and a child that adds a cross-tag conjunct produces an unsatisfiable conjunction — fail closed, never a widening (REQ2-SELECTOR-attenuation-unchanged).

5. Requirement identifiers

The v2 profile carries its own REQ2-* range per ADR 0007; REQ1-* ids remain bound to the v1 profile and never apply to v2 behavior. The v2 MUST-to-cell traceability lives in the requirement map § v2.

6. Conformance corpus

The v2 conformance corpus is a certified artifact with its own identity (priv/conformance/v2/corpus, 268 cases across the 28 surfaces, 16 classes, revision 1). Its certified index SHA-256 is pinned in the verifier CLI and every SDK runner exactly as the v1 corpus is (ADR 0014 D4). Version-neutral primitive surfaces (JSON/JCS/base64url/JWK/URI/bounds) execute the same shared implementations the v1 corpus certifies, and their cases are carried into the v2 corpus byte-for-byte; the profile-bound surfaces carry v2-minted fixtures, the full range-selector applicability classes, and cross-major rejection vectors. Signed fixtures were minted with ephemeral in-memory Ed25519 keys; no private material is tracked (REQ2-CORPUS-certified-identity).