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equals.ts
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equals.ts
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import * as crypto from 'crypto';
/**
* Constant-time buffer comparison
*
* @param {Uint8Array} left
* @param {Uint8Array} right
* @returns {boolean}
*/
export function equals(left: Uint8Array, right: Uint8Array): boolean {
if (left.length !== right.length) {
return false;
}
let d: number = 0;
let i: number;
for (i = 0; i < left.length; i++) {
d |= left[i] ^ right[i];
}
return d === 0;
}
/**
* Constant-time equality even with an adversarial JIT compiler.
*
* @param {Uint8Array} left
* @param {Uint8Array} right
* @returns {boolean}
*/
export function hmac_equals(left: Uint8Array, right: Uint8Array): boolean {
return equals(
crypto.createHmac('sha256', hmacKey).update(left).digest(),
crypto.createHmac('sha256', hmacKey).update(right).digest()
);
}
const hmacKey = crypto.randomBytes(32);