Crate structured_xades

Expand description

§structured-xades

Provider-neutral XAdES mechanisms with explicit memory and work accounting. The crate supports no_std + alloc and performs no implicit I/O.

An XML adapter supplies the original document, stable node identities, authenticated reference instructions and transformed byte streams. Cryptographic providers supply digest and signature operations: digests through the shared structured_asn1::digest::Digest contract, with certificate::DigestProvider adding only XML DigestMethod resolution and classification. Application code supplies trust inputs and decides whether the resulting evidence meets its policy.

§Processing the original signature

prepare::prepare binds the selected signature to its complete protected SignedProperties and inventories its original properties and references.
prepare::check_fields checks declared attributes, URI/OID fields, optional validation-reference scalar/binary syntax and the claimed signing time before certificate or provider effects. Unsigned certificate references remain a distinct model and cannot substitute for protected signing-certificate binding. validation separately compares original whole-artifact digests, RFC 4514 issuer/responder names and exact identifier time labels, and reads DER issuer/serial and OCSP byKey hints through the shared PKIX/CMS kernels. validation::compare_reference_catalogues visits every prepared reference and every compatible parsed XML material source, including certificates embedded in OCSP. It retains all comparison outcomes and original source ordinals while sharing finished hashes for identical artifacts and complete resolved algorithm identities. Responder-key matching uses the same OCSP identity kernel as response authentication; it does not repeat signatures. compare_reference_catalogues_with_tokens includes the separate original timestamp pool, including carried CRLs, whole OCSP envelopes and embedded certificates. Pool identities remain explicit and identical copies reuse one finished digest. reference_presence checks conditional incorporation against the complete original token/counter census; unavailable methods and identifier-only references remain unproven rather than becoming missing values. External parsed certificates, CRLs and whole OCSP responses can be compared through compare_reference_target without manufacturing XML copies. check_root_certificate_references covers the actual root CA/anchor path and excludes its signing certificate with the same digest memo. Its result does not assert the separate credential/TSA role rules. check_certificate_reference_roles checks ordinary references against the complete actual credential CA census, preserving shared TSA/signature uses and indeterminate older-certificate CA facts. It reuses the same lazy CA and digest kernels; it does not establish attribute-reference completeness. check_credential_certificate_references derives the required credential signer, ancestor and existing-anchor set from actual participant paths. Original protected and ordinary references can satisfy that set; redundant attribute copies remain a separate advisory finding. All sources share one certificate/provider memo, and absent optional properties need no catalogue. check_revocation_reference_roles applies the corresponding rule to actual status targets. It associates known basic OCSP bodies with their original whole XML/carried envelopes; missing envelopes remain unproven, with no payload substitution. It also retains every actual signer-path status contributor, including both lists of a delta source, and reports whether written ordinary references cover that required set. All comparisons reuse one exact-artifact/provider memo. Credential paths retain every non-anchor complete/delta or OCSP contributor too: ordinary and attribute references provide the A.1.4 alternatives, with redundant attribute copies reported as advisory. Attribute rows do not satisfy the signer’s ordinary-reference set. Missing original whole OCSP envelopes remain unproven in either role. Shared status uses retain all participant purposes; source presence alone does not validate identifier hints or grade. check_crl_reference and check_ocsp_reference compose original issuer/responder and issue/production time facts; OCSP uses its authenticated signer and preflights mandatory time syntax before provider effects. check_ocsp_envelope_reference also binds that authenticated body to the exact whole response whose digest is checked; an identifier from another signed response cannot satisfy that relation. Its receipt retains the original property/row, whole envelope and signed response/signer. identifies_response requires both identifier fields and the digest when written. A legitimate identifier-only reference remains distinguishable through digest(); it does not protect the whole contents against substitution or establish status or trust. check_crl_value_reference likewise binds optional issuer/time fields and the mandatory whole-list digest to one actual parsed CRL. Its receipt retains the original property, row and list; independently successful facts from two lists cannot be combined. Missing optional identifiers remain valid when the digest identifies the list, while unreadable time prevents provider dispatch. None of these facts alone establishes a grade.
certificate, counter, hashes, credential, timestamp and pki establish their respective source-bound facts. The participant census includes plain countersignatures and timestamps nested in countersignatures. The timestamp census also retains the optional Annex A signature/reference and reference-only timestamps; their implicit inputs preserve original preceding-property order rather than reusing archive coverage.
baseline::basic joins the checked fields, exact signing certificate, effective key, counter paths and actual hash uses. Every written protected, ordinary and attribute certificate-reference issuer hint uses the same DER reader. Located readable encoding faults prevent a positive basic predicate; original catalogue ordinals remain available through HintSource. A hint never replaces certificate digest binding. As specified in §5.2.2 Note 2, optional IssuerSerialV2 contents are retrieval hints: their agreement is not an additional binding requirement. The hint reports describe DER syntax, rather than asserting that their issuer/serial matches a selected certificate.
baseline::timestamped requires the complete token census and records each root signature timestamp’s static time association.
material::check_participants and material::credentials::check examine the complete participant/status closure. baseline::long_term joins those original reports with the preceding receipts.
For each archive, derive the preceding-participant closure and original element coverage. baseline::archive_material joins the X.509 and credential material reports for that archive; baseline::archives requires every root archive once, in original order. renewed::check_prepared separately processes every written root renewal’s original Manifest instructions and digest pairs, retaining failed comparisons alongside successful ones.
baseline::assess takes the stage reports of exactly the level that the preparation requested: Evidence::basic for B-B, Evidence::timestamped for B-T, Evidence::LongTerm for B-LT, and Evidence::Archival (the long_term and archives reports) for B-LTA. It refuses a different level, or an archive census built from another preparation or another authenticated credential census than the whole signature. The result states whether every condition of that level holds, including the earlier levels.

Receipts keep detailed negative findings. A material-presence predicate does not establish usable revocation status, historical trust, timestamp chronology or algorithm longevity. The requested structural B-B/B-T/B-LT/B-LTA requirements remain distinct from verified evidence and application acceptance. Extra containers do not promote a result to a higher level.

§Current-operation accounting

Every query receives its current Work, including queries over previously retained document data. For example, base-datatype validation delegates to the XML owner’s original scalar kernel:

use structured_asn1::memory::Work;
use structured_xades::{
    reference::LexicalSource,
    scalar::{self, Datatype, ScalarResult, ScalarXml},
    xml::Access,
};

fn check_original_uri<X: ScalarXml, W: Work>(
    access: &Access<'_, X, W>,
    node: X::Id,
) -> ScalarResult<X> {
    scalar::check(access, node, LexicalSource::SimpleContent, Datatype::AnyUri)
}

Allocation capacity remains charged for its lifetime. New traversal, normalization, copying and provider work require admission before execution; retained facts provide no credit for later work. Scoped normalized values cannot escape their visitor. Source/generation changes, resource failures and callback errors remain processing failures, separate from malformed, unsupported, missing or mismatching evidence.

§Adapter boundary

An adapter must preserve original signature selection, reference identity, namespace interpretation, canonicalization choices and transformed bytes. QName syntax, original namespace resolution and scalar normalization belong to the XML owner. QNameXml retains the original lexical reading and separates an unbound prefix from malformed text and processing refusal. The attribute kernel accepts an explicit type equal to the actual pinned declaration, including contextual Cert/CertifiedRole/RecomputedDigestValue declarations. Overriding types needing other derivation/content validation remain explicitly unassessed; a resolved name alone never certifies them. Schema hints do not trigger fetches. The generic core contains no second XML parser, canonicalizer, URI resolver or crypto backend. Synthetic XML fixtures exercise the generic contracts; actual XML adapter and interoperability qualification are separate requirements.

The repository’s scripts/qualify-xades-corpus.py checks SHA256-pinned public DSS fixtures (B-B, B-LT and B-LTA, negative and signature-wrapping cases, and a document with two signatures) using test-only xmlsec1/OpenSSL and libxml2 C14N through lxml. It compares the common signature/archive input streams byte-for-byte with independently canonicalized/transformed inputs and their signed token imprints, verifies XML/CMS and OCSP mathematics, including isolated signature and data mutations, and checks each negative fixture’s stated defect. Upstream payloads and their licence notice remain outside packages in target/. These external tools are test oracles; the Rust runtime gains no FFI dependency. Historical trust, revocation acceptance and the bounded native XML adapter remain separate checks.

Modules§

attributes: Original XAdES attribute declarations and their base-datatype obligations.
baseline: Composition of source-bound baseline facts, separate from caller trust.
binary: Scoped ASN.1 carried by original XML nodes, without retaining decoded buffers.
binding: Selected-signature binding, separate from property validation and path trust.
certificate: Original signing-certificate references, before digest/path validation.
commitment: Original signed commitments and their authenticated Reference associations.
container: Original direct-incorporation containers of a selected XML signature.
counter: Original enveloped countersignature selection and XMLDSig coverage binding.
credential: Source-bound independent credentials and their actual authority paths.
digest: Streaming XML digest checks through the caller’s selected provider.
format: Baseline data-object format structure, reference coverage and object agreement.
hashes: Baseline MD5 guard over actual XML-owner hash-use receipts.
header: Baseline XMLDSig header requirements, separate from selected-key/path trust.
identifier: The one original-source ObjectIdentifierType structural kernel.
material: Original embedded validation material, separate from authentication/completeness.
pki: Original certificate-path facts for validation-material accounting.
policy: Original signature-policy declarations, distinct from application policy.
prepare: One original-source preparation path for subsequent baseline execution.
properties: Bound original signed-property roles, before their scalar/PKI checks.
reference: Authenticated reference resolution shared by signed property mechanisms.
renewed: Original renewed detached-object digests, before reference/hash comparisons.
role: Original signed role claims, distinct from independently validated credentials.
scalar: Original XML base-datatype syntax, separate from authenticated properties.
timestamp: Timestamp input selection and streaming over original XML owner ranges.
unsigned: Complete unsigned-property inventory and requested-profile presence rules.
validation: Validation-data containers and non-authoritative timestamp association hints.
xml: Scoped XML access without retaining DOM or callback-local string borrows.