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- import { hash as assertHash, bytes as assertBytes, exists as assertExists } from './_assert.js';
- import { Hash, toBytes } from './utils.js';
- // HMAC (RFC 2104)
- export class HMAC extends Hash {
- constructor(hash, _key) {
- super();
- this.finished = false;
- this.destroyed = false;
- assertHash(hash);
- const key = toBytes(_key);
- this.iHash = hash.create();
- if (typeof this.iHash.update !== 'function')
- throw new Error('Expected instance of class which extends utils.Hash');
- this.blockLen = this.iHash.blockLen;
- this.outputLen = this.iHash.outputLen;
- const blockLen = this.blockLen;
- const pad = new Uint8Array(blockLen);
- // blockLen can be bigger than outputLen
- pad.set(key.length > blockLen ? hash.create().update(key).digest() : key);
- for (let i = 0; i < pad.length; i++)
- pad[i] ^= 0x36;
- this.iHash.update(pad);
- // By doing update (processing of first block) of outer hash here we can re-use it between multiple calls via clone
- this.oHash = hash.create();
- // Undo internal XOR && apply outer XOR
- for (let i = 0; i < pad.length; i++)
- pad[i] ^= 0x36 ^ 0x5c;
- this.oHash.update(pad);
- pad.fill(0);
- }
- update(buf) {
- assertExists(this);
- this.iHash.update(buf);
- return this;
- }
- digestInto(out) {
- assertExists(this);
- assertBytes(out, this.outputLen);
- this.finished = true;
- this.iHash.digestInto(out);
- this.oHash.update(out);
- this.oHash.digestInto(out);
- this.destroy();
- }
- digest() {
- const out = new Uint8Array(this.oHash.outputLen);
- this.digestInto(out);
- return out;
- }
- _cloneInto(to) {
- // Create new instance without calling constructor since key already in state and we don't know it.
- to || (to = Object.create(Object.getPrototypeOf(this), {}));
- const { oHash, iHash, finished, destroyed, blockLen, outputLen } = this;
- to = to;
- to.finished = finished;
- to.destroyed = destroyed;
- to.blockLen = blockLen;
- to.outputLen = outputLen;
- to.oHash = oHash._cloneInto(to.oHash);
- to.iHash = iHash._cloneInto(to.iHash);
- return to;
- }
- destroy() {
- this.destroyed = true;
- this.oHash.destroy();
- this.iHash.destroy();
- }
- }
- /**
- * HMAC: RFC2104 message authentication code.
- * @param hash - function that would be used e.g. sha256
- * @param key - message key
- * @param message - message data
- */
- export const hmac = (hash, key, message) => new HMAC(hash, key).update(message).digest();
- hmac.create = (hash, key) => new HMAC(hash, key);
- //# sourceMappingURL=hmac.js.map
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