@li0ard/kupyna/dist/modes/kmac.js

Kupyna (DSTU 7564:2014) hash function in pure TypeScript

import { dpad } from "../const.js";
import { uint64sToBytes } from "../utils.js";
/** Abstract class for Kupyna KMAC */
export class KupynaKMAC {
    key;
    outputLen;
    blockLen;
    threshold;
    h;
    ik;
    len;
    constructor(hash, kpad, key) {
        this.key = key;
        this.len = 0n;
        this.h = hash();
        this.outputLen = this.h.outputLen;
        this.blockLen = this.h.blockLen;
        if (key.length != this.h.outputLen)
            throw new Error("Invalid key length");
        this.h.update(key);
        this.h.update(kpad);
        this.ik = new Uint8Array(key.length);
        for (let i = 0; i < key.length; i++)
            this.ik[i] = ~key[i] & 0xFF;
        this.threshold = this.blockLen - 12;
    }
    /** Update hash buffer */
    update(data) {
        this.len += BigInt(data.length);
        this.h.update(data);
        return this;
    }
    /** Finalize hash computation and return result as Uint8Array */
    digest() { return this.clone().final(); }
    final() {
        let n = this.len;
        let pad_size;
        if (n < BigInt(this.threshold))
            pad_size = (BigInt(this.threshold) - 1n) - n;
        else
            pad_size = (BigInt(this.blockLen) - 1n) - ((n - BigInt(this.threshold)) % BigInt(this.blockLen));
        n *= 8n;
        this.h.update(dpad.slice(0, Number(pad_size + 1n)));
        this.h.update(uint64sToBytes(new BigUint64Array([n])));
        this.h.update(dpad.slice(16, 20));
        this.h.update(this.ik);
        return this.h.digest();
    }
}