2025-12-03 20:54:35 +01:00

188 lines
7.7 KiB
JavaScript

import { FlattenedEncrypt } from '../flattened/encrypt.js';
import { unprotected } from '../../lib/private_symbols.js';
import { JOSENotSupported, JWEInvalid } from '../../util/errors.js';
import { generateCek } from '../../lib/cek.js';
import { isDisjoint } from '../../lib/is_disjoint.js';
import { encryptKeyManagement } from '../../lib/encrypt_key_management.js';
import { encode as b64u } from '../../util/base64url.js';
import { validateCrit } from '../../lib/validate_crit.js';
import { normalizeKey } from '../../lib/normalize_key.js';
import { checkKeyType } from '../../lib/check_key_type.js';
class IndividualRecipient {
#parent;
unprotectedHeader;
keyManagementParameters;
key;
options;
constructor(enc, key, options) {
this.#parent = enc;
this.key = key;
this.options = options;
}
setUnprotectedHeader(unprotectedHeader) {
if (this.unprotectedHeader) {
throw new TypeError('setUnprotectedHeader can only be called once');
}
this.unprotectedHeader = unprotectedHeader;
return this;
}
setKeyManagementParameters(parameters) {
if (this.keyManagementParameters) {
throw new TypeError('setKeyManagementParameters can only be called once');
}
this.keyManagementParameters = parameters;
return this;
}
addRecipient(...args) {
return this.#parent.addRecipient(...args);
}
encrypt(...args) {
return this.#parent.encrypt(...args);
}
done() {
return this.#parent;
}
}
export class GeneralEncrypt {
#plaintext;
#recipients = [];
#protectedHeader;
#unprotectedHeader;
#aad;
constructor(plaintext) {
this.#plaintext = plaintext;
}
addRecipient(key, options) {
const recipient = new IndividualRecipient(this, key, { crit: options?.crit });
this.#recipients.push(recipient);
return recipient;
}
setProtectedHeader(protectedHeader) {
if (this.#protectedHeader) {
throw new TypeError('setProtectedHeader can only be called once');
}
this.#protectedHeader = protectedHeader;
return this;
}
setSharedUnprotectedHeader(sharedUnprotectedHeader) {
if (this.#unprotectedHeader) {
throw new TypeError('setSharedUnprotectedHeader can only be called once');
}
this.#unprotectedHeader = sharedUnprotectedHeader;
return this;
}
setAdditionalAuthenticatedData(aad) {
this.#aad = aad;
return this;
}
async encrypt() {
if (!this.#recipients.length) {
throw new JWEInvalid('at least one recipient must be added');
}
if (this.#recipients.length === 1) {
const [recipient] = this.#recipients;
const flattened = await new FlattenedEncrypt(this.#plaintext)
.setAdditionalAuthenticatedData(this.#aad)
.setProtectedHeader(this.#protectedHeader)
.setSharedUnprotectedHeader(this.#unprotectedHeader)
.setUnprotectedHeader(recipient.unprotectedHeader)
.encrypt(recipient.key, { ...recipient.options });
const jwe = {
ciphertext: flattened.ciphertext,
iv: flattened.iv,
recipients: [{}],
tag: flattened.tag,
};
if (flattened.aad)
jwe.aad = flattened.aad;
if (flattened.protected)
jwe.protected = flattened.protected;
if (flattened.unprotected)
jwe.unprotected = flattened.unprotected;
if (flattened.encrypted_key)
jwe.recipients[0].encrypted_key = flattened.encrypted_key;
if (flattened.header)
jwe.recipients[0].header = flattened.header;
return jwe;
}
let enc;
for (let i = 0; i < this.#recipients.length; i++) {
const recipient = this.#recipients[i];
if (!isDisjoint(this.#protectedHeader, this.#unprotectedHeader, recipient.unprotectedHeader)) {
throw new JWEInvalid('JWE Protected, JWE Shared Unprotected and JWE Per-Recipient Header Parameter names must be disjoint');
}
const joseHeader = {
...this.#protectedHeader,
...this.#unprotectedHeader,
...recipient.unprotectedHeader,
};
const { alg } = joseHeader;
if (typeof alg !== 'string' || !alg) {
throw new JWEInvalid('JWE "alg" (Algorithm) Header Parameter missing or invalid');
}
if (alg === 'dir' || alg === 'ECDH-ES') {
throw new JWEInvalid('"dir" and "ECDH-ES" alg may only be used with a single recipient');
}
if (typeof joseHeader.enc !== 'string' || !joseHeader.enc) {
throw new JWEInvalid('JWE "enc" (Encryption Algorithm) Header Parameter missing or invalid');
}
if (!enc) {
enc = joseHeader.enc;
}
else if (enc !== joseHeader.enc) {
throw new JWEInvalid('JWE "enc" (Encryption Algorithm) Header Parameter must be the same for all recipients');
}
validateCrit(JWEInvalid, new Map(), recipient.options.crit, this.#protectedHeader, joseHeader);
if (joseHeader.zip !== undefined) {
throw new JOSENotSupported('JWE "zip" (Compression Algorithm) Header Parameter is not supported.');
}
}
const cek = generateCek(enc);
const jwe = {
ciphertext: '',
recipients: [],
};
for (let i = 0; i < this.#recipients.length; i++) {
const recipient = this.#recipients[i];
const target = {};
jwe.recipients.push(target);
if (i === 0) {
const flattened = await new FlattenedEncrypt(this.#plaintext)
.setAdditionalAuthenticatedData(this.#aad)
.setContentEncryptionKey(cek)
.setProtectedHeader(this.#protectedHeader)
.setSharedUnprotectedHeader(this.#unprotectedHeader)
.setUnprotectedHeader(recipient.unprotectedHeader)
.setKeyManagementParameters(recipient.keyManagementParameters)
.encrypt(recipient.key, {
...recipient.options,
[unprotected]: true,
});
jwe.ciphertext = flattened.ciphertext;
jwe.iv = flattened.iv;
jwe.tag = flattened.tag;
if (flattened.aad)
jwe.aad = flattened.aad;
if (flattened.protected)
jwe.protected = flattened.protected;
if (flattened.unprotected)
jwe.unprotected = flattened.unprotected;
target.encrypted_key = flattened.encrypted_key;
if (flattened.header)
target.header = flattened.header;
continue;
}
const alg = recipient.unprotectedHeader?.alg ||
this.#protectedHeader?.alg ||
this.#unprotectedHeader?.alg;
checkKeyType(alg === 'dir' ? enc : alg, recipient.key, 'encrypt');
const k = await normalizeKey(recipient.key, alg);
const { encryptedKey, parameters } = await encryptKeyManagement(alg, enc, k, cek, recipient.keyManagementParameters);
target.encrypted_key = b64u(encryptedKey);
if (recipient.unprotectedHeader || parameters)
target.header = { ...recipient.unprotectedHeader, ...parameters };
}
return jwe;
}
}