import * as aeskw from './aeskw.js'; import * as ecdhes from './ecdhes.js'; import * as pbes2kw from './pbes2kw.js'; import * as rsaes from './rsaes.js'; import { decode as b64u } from '../util/base64url.js'; import { JOSENotSupported, JWEInvalid } from '../util/errors.js'; import { cekLength } from '../lib/cek.js'; import { importJWK } from '../key/import.js'; import { isObject } from './is_object.js'; import { unwrap as aesGcmKw } from './aesgcmkw.js'; import { assertCryptoKey } from './is_key_like.js'; export async function decryptKeyManagement(alg, key, encryptedKey, joseHeader, options) { switch (alg) { case 'dir': { if (encryptedKey !== undefined) throw new JWEInvalid('Encountered unexpected JWE Encrypted Key'); return key; } case 'ECDH-ES': if (encryptedKey !== undefined) throw new JWEInvalid('Encountered unexpected JWE Encrypted Key'); case 'ECDH-ES+A128KW': case 'ECDH-ES+A192KW': case 'ECDH-ES+A256KW': { if (!isObject(joseHeader.epk)) throw new JWEInvalid(`JOSE Header "epk" (Ephemeral Public Key) missing or invalid`); assertCryptoKey(key); if (!ecdhes.allowed(key)) throw new JOSENotSupported('ECDH with the provided key is not allowed or not supported by your javascript runtime'); const epk = await importJWK(joseHeader.epk, alg); assertCryptoKey(epk); let partyUInfo; let partyVInfo; if (joseHeader.apu !== undefined) { if (typeof joseHeader.apu !== 'string') throw new JWEInvalid(`JOSE Header "apu" (Agreement PartyUInfo) invalid`); try { partyUInfo = b64u(joseHeader.apu); } catch { throw new JWEInvalid('Failed to base64url decode the apu'); } } if (joseHeader.apv !== undefined) { if (typeof joseHeader.apv !== 'string') throw new JWEInvalid(`JOSE Header "apv" (Agreement PartyVInfo) invalid`); try { partyVInfo = b64u(joseHeader.apv); } catch { throw new JWEInvalid('Failed to base64url decode the apv'); } } const sharedSecret = await ecdhes.deriveKey(epk, key, alg === 'ECDH-ES' ? joseHeader.enc : alg, alg === 'ECDH-ES' ? cekLength(joseHeader.enc) : parseInt(alg.slice(-5, -2), 10), partyUInfo, partyVInfo); if (alg === 'ECDH-ES') return sharedSecret; if (encryptedKey === undefined) throw new JWEInvalid('JWE Encrypted Key missing'); return aeskw.unwrap(alg.slice(-6), sharedSecret, encryptedKey); } case 'RSA-OAEP': case 'RSA-OAEP-256': case 'RSA-OAEP-384': case 'RSA-OAEP-512': { if (encryptedKey === undefined) throw new JWEInvalid('JWE Encrypted Key missing'); assertCryptoKey(key); return rsaes.decrypt(alg, key, encryptedKey); } case 'PBES2-HS256+A128KW': case 'PBES2-HS384+A192KW': case 'PBES2-HS512+A256KW': { if (encryptedKey === undefined) throw new JWEInvalid('JWE Encrypted Key missing'); if (typeof joseHeader.p2c !== 'number') throw new JWEInvalid(`JOSE Header "p2c" (PBES2 Count) missing or invalid`); const p2cLimit = options?.maxPBES2Count || 10_000; if (joseHeader.p2c > p2cLimit) throw new JWEInvalid(`JOSE Header "p2c" (PBES2 Count) out is of acceptable bounds`); if (typeof joseHeader.p2s !== 'string') throw new JWEInvalid(`JOSE Header "p2s" (PBES2 Salt) missing or invalid`); let p2s; try { p2s = b64u(joseHeader.p2s); } catch { throw new JWEInvalid('Failed to base64url decode the p2s'); } return pbes2kw.unwrap(alg, key, encryptedKey, joseHeader.p2c, p2s); } case 'A128KW': case 'A192KW': case 'A256KW': { if (encryptedKey === undefined) throw new JWEInvalid('JWE Encrypted Key missing'); return aeskw.unwrap(alg, key, encryptedKey); } case 'A128GCMKW': case 'A192GCMKW': case 'A256GCMKW': { if (encryptedKey === undefined) throw new JWEInvalid('JWE Encrypted Key missing'); if (typeof joseHeader.iv !== 'string') throw new JWEInvalid(`JOSE Header "iv" (Initialization Vector) missing or invalid`); if (typeof joseHeader.tag !== 'string') throw new JWEInvalid(`JOSE Header "tag" (Authentication Tag) missing or invalid`); let iv; try { iv = b64u(joseHeader.iv); } catch { throw new JWEInvalid('Failed to base64url decode the iv'); } let tag; try { tag = b64u(joseHeader.tag); } catch { throw new JWEInvalid('Failed to base64url decode the tag'); } return aesGcmKw(alg, key, encryptedKey, iv, tag); } default: { throw new JOSENotSupported('Invalid or unsupported "alg" (JWE Algorithm) header value'); } } }