pdfPermissions

/P decoding + /Perms verification — ISO 32000-2 §7.6.3.2 Table 22.

Module pdfPermissions | Source packages/front/office/pdf/src/crypto/permissions.js | Deps pdfErrors, aes | Worker-safe yes

The /P field is a signed 32-bit integer whose bits encode permissions (bit 3 = print, 4 = modify, 5 = copy/extract, 6 = annotate, 9 = fill forms, 10 = accessibility extraction, 11 = assemble, 12 = high-quality print). verifyPermsField decrypts the 16-byte /Perms string (AES-256-ECB with the FEK) and checks that it encodes the same /P — a de facto MAC protecting against post-encryption tampering.

Resolve

const perms = runtime.resolve('pdfPermissions');
// Returns: { decodePermissions, verifyPermsField }

API

Shape PermFlags

{
    raw: number,
    print: boolean,             // bit 3
    modify: boolean,            // bit 4
    copy: boolean,               // bit 5
    annot: boolean,              // bit 6
    formFill: boolean,           // bit 9
    accessible: boolean,         // bit 10 — accessibility extraction
    assemble: boolean,           // bit 11
    printHighQuality: boolean    // bit 12
}

Examples

Decoding the flags

const p = runtime.resolve('pdfPermissions').decodePermissions(enc.P);
if (!p.copy) viewer.disableTextSelection();

MAC verification

const v = perms.verifyPermsField(enc, fek);
if (!v.ok) throw new Error('permissions tampered');
v.encryptMetadata === enc.EncryptMetadata;

Errors

See also

• pdfSecurity · pdfStandardV5 · pdfStandardV6