awaforge

pdfSha1

AGPL-3.0-onlyRelease 2L4

SHA-1 (FIPS 180-4 §6.1) — PDF-local legacy hash, DSS /VRI keys only.

Module pdfSha1 | Source packages/front/office/pdf/src/sig/sha1.js | Deps bitArray, utf8 | Worker-safe yes

SHA-1 is cryptographically broken for collision resistance and must not be used for new signatures, MACs, or password hashing. This module exists solely because ISO 32000-2 §12.8.4.3 mandates SHA-1 of the signature value as the DSS /VRI dict key — kept in @awacloud/pdf rather than @awacloud/fw so the legacy-only nature stays obvious to anyone reading fw's hash family (sha256/sha384/sha512 only, no sha1). Exposes the same shape as fw's hash modules (hash(data) one-shot, fn() constructor) so dispatch code can treat it uniformly.

Resolve

const sha1 = runtime.resolve('pdfSha1');
// Returns: { fn, hash }

API

Method Signature Returns
hash (data: Uint8Array | bitArray | string) => bitArray One-shot digest (20 bytes as a fw bitArray).
fn (other?: HashState) => HashState Streaming constructor — { reset, update, finalize, blockSize: 512 }. Passing an existing instance clones its internal state.

update(data) accepts a string (UTF-8 encoded via utf8.toBytes then converted to a bitArray) or an already-encoded bitArray.

Examples

One-shot digest

const sha1 = runtime.resolve('pdfSha1');
const bitArrayMod = runtime.resolve('bitArray');
const digest = sha1.hash(bitArrayMod.ui8_to_ba(signatureValueBytes));
const bytes = bitArrayMod.ba_to_ui8(digest); // 20 bytes

Streaming

const sha1 = runtime.resolve('pdfSha1');
const ctx = sha1.fn();
ctx.update(chunk1).update(chunk2);
const digest = ctx.finalize();

Errors

None thrown. update() guards against hashing more than 2^53 − 1 bits by console.warn-ing and returning false instead of throwing — a limit that is unreachable for the DSS VRI-key use case (hashing a single signature value, at most a few KB).

See also

  • pdfDssBuilder — the only consumer, for /VRI key derivation.
  • pdfSignature — uses fw's sha256/sha384/sha512 for the actual signature digest.