sneak
78fdabe54a
The implementation is exactly the decryption chain documented in the test file: deriveKEK -> decryptBox(masterKey) -> decryptBox(secretKey) -> decryptSealed(token) -> toBase64URL. Errors from the underlying crypto primitives propagate; the only added validation is the up-front check that the response actually contains both keyAttributes and encryptedToken (caller bug if not). Also re-exports the auth/unwrap and auth/types public surface from src/index.ts. All 38 tests pass; make check and make docker are green.
65 lines
1.9 KiB
TypeScript
65 lines
1.9 KiB
TypeScript
import {
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decryptBox,
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decryptSealed,
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deriveKEK,
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fromBase64,
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toBase64URL,
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} from "../crypto/index.js";
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import type { AuthorizationResponse } from "./types.js";
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export interface UnwrapResult {
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masterKey: Uint8Array;
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secretKey: Uint8Array;
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publicKey: Uint8Array;
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// URL-safe-no-padding base64 of the decrypted token bytes; this is the
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// exact value to put in the X-Auth-Token header on subsequent calls.
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token: string;
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}
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// Given a successful AuthorizationResponse and the user's password,
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// derive the KEK, decrypt the master key, decrypt the secret key, and
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// open the sealed auth token. See test/auth/unwrap.test.ts for the
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// complete protocol description.
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export const unwrapAuth = async (
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response: AuthorizationResponse,
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password: string,
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): Promise<UnwrapResult> => {
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if (!response.keyAttributes) {
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throw new Error(
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"unwrapAuth: response.keyAttributes is required (login may be incomplete: TOTP or passkey pending)",
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);
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}
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if (!response.encryptedToken) {
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throw new Error(
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"unwrapAuth: response.encryptedToken is required (login may be incomplete: TOTP or passkey pending)",
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);
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}
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const ka = response.keyAttributes;
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const kek = await deriveKEK(
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password,
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fromBase64(ka.kekSalt),
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ka.opsLimit,
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ka.memLimit,
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);
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const masterKey = decryptBox(
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fromBase64(ka.encryptedKey),
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fromBase64(ka.keyDecryptionNonce),
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kek,
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);
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const secretKey = decryptBox(
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fromBase64(ka.encryptedSecretKey),
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fromBase64(ka.secretKeyDecryptionNonce),
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masterKey,
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);
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const publicKey = fromBase64(ka.publicKey);
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const tokenBytes = decryptSealed(
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fromBase64(response.encryptedToken),
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publicKey,
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secretKey,
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);
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const token = toBase64URL(tokenBytes);
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return { masterKey, secretKey, publicKey, token };
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};
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