/*! noble-ciphers - MIT License (c) 2023 Paul Miller (paulmillr.com) */
// micro-noble-ciphers: more auditable, but slower version of salsa20, chacha & poly1305.
// Implements the same algorithms that are present in other files,
// but without unrolled loops (https://en.wikipedia.org/wiki/Loop_unrolling).
import * as u from './utils.js';
import { salsaBasic } from './_salsa.js';
// Utils
function hexToNumber(hex) {
    if (typeof hex !== 'string')
        throw new Error('hex string expected, got ' + typeof hex);
    // Big Endian
    return BigInt(hex === '' ? '0' : `0x${hex}`);
}
function bytesToNumberLE(bytes) {
    return hexToNumber(u.bytesToHex(Uint8Array.from(bytes).reverse()));
}
function numberToBytesLE(n, len) {
    return u.hexToBytes(n.toString(16).padStart(len * 2, '0')).reverse();
}
const rotl = (a, b) => (a << b) | (a >>> (32 - b));
// /Utils
function salsaQR(x, a, b, c, d) {
    x[b] ^= rotl((x[a] + x[d]) | 0, 7);
    x[c] ^= rotl((x[b] + x[a]) | 0, 9);
    x[d] ^= rotl((x[c] + x[b]) | 0, 13);
    x[a] ^= rotl((x[d] + x[c]) | 0, 18);
}
// prettier-ignore
function chachaQR(x, a, b, c, d) {
    x[a] = (x[a] + x[b]) | 0;
    x[d] = rotl(x[d] ^ x[a], 16);
    x[c] = (x[c] + x[d]) | 0;
    x[b] = rotl(x[b] ^ x[c], 12);
    x[a] = (x[a] + x[b]) | 0;
    x[d] = rotl(x[d] ^ x[a], 8);
    x[c] = (x[c] + x[d]) | 0;
    x[b] = rotl(x[b] ^ x[c], 7);
}
function salsaRound(x, rounds = 20) {
    for (let i = 0; i < rounds; i += 2) {
        salsaQR(x, 0, 4, 8, 12);
        salsaQR(x, 5, 9, 13, 1);
        salsaQR(x, 10, 14, 2, 6);
        salsaQR(x, 15, 3, 7, 11);
        salsaQR(x, 0, 1, 2, 3);
        salsaQR(x, 5, 6, 7, 4);
        salsaQR(x, 10, 11, 8, 9);
        salsaQR(x, 15, 12, 13, 14);
    }
}
function chachaRound(x, rounds = 20) {
    for (let i = 0; i < rounds; i += 2) {
        chachaQR(x, 0, 4, 8, 12);
        chachaQR(x, 1, 5, 9, 13);
        chachaQR(x, 2, 6, 10, 14);
        chachaQR(x, 3, 7, 11, 15);
        chachaQR(x, 0, 5, 10, 15);
        chachaQR(x, 1, 6, 11, 12);
        chachaQR(x, 2, 7, 8, 13);
        chachaQR(x, 3, 4, 9, 14);
    }
}
function salsaCore(c, k, n, out, cnt, rounds = 20) {
    // prettier-ignore
    const y = new Uint32Array([
        c[0], k[0], k[1], k[2],
        k[3], c[1], n[0], n[1],
        cnt, 0, c[2], k[4],
        k[5], k[6], k[7], c[3], // Key    Key     Key     "te k"
    ]);
    const x = y.slice();
    salsaRound(x, rounds);
    for (let i = 0; i < 16; i++)
        out[i] = (y[i] + x[i]) | 0;
}
export function hsalsa(c, key, nonce) {
    const k = u.u32(key);
    const i = u.u32(nonce);
    // prettier-ignore
    const x = new Uint32Array([
        c[0], k[0], k[1], k[2],
        k[3], c[1], i[0], i[1],
        i[2], i[3], c[2], k[4],
        k[5], k[6], k[7], c[3]
    ]);
    salsaRound(x);
    return u.u8(new Uint32Array([x[0], x[5], x[10], x[15], x[6], x[7], x[8], x[9]]));
}
function chachaCore(c, k, n, out, cnt, rounds = 20) {
    // prettier-ignore
    const y = new Uint32Array([
        c[0], c[1], c[2], c[3],
        k[0], k[1], k[2], k[3],
        k[4], k[5], k[6], k[7],
        cnt, n[0], n[1], n[2], // Counter  Counter	Nonce   Nonce
    ]);
    const x = y.slice();
    chachaRound(x, rounds);
    for (let i = 0; i < 16; i++)
        out[i] = (y[i] + x[i]) | 0;
}
export function hchacha(c, key, nonce) {
    const k = u.u32(key);
    const i = u.u32(nonce);
    // prettier-ignore
    const x = new Uint32Array([
        c[0], c[1], c[2], c[3],
        k[0], k[1], k[2], k[3],
        k[4], k[5], k[6], k[7],
        i[0], i[1], i[2], i[3],
    ]);
    chachaRound(x);
    return u.u8(new Uint32Array([x[0], x[1], x[2], x[3], x[12], x[13], x[14], x[15]]));
}
/**
 * salsa20, 12-byte nonce.
 */
export const salsa20 = salsaBasic({ core: salsaCore, counterRight: true });
/**
 * xsalsa20, 24-byte nonce.
 */
export const xsalsa20 = salsaBasic({
    core: salsaCore,
    counterRight: true,
    extendNonceFn: hsalsa,
    allow128bitKeys: false,
});
/**
 * chacha20 non-RFC, original version by djb. 8-byte nonce, 8-byte counter.
 */
export const chacha20orig = salsaBasic({ core: chachaCore, counterRight: false, counterLen: 8 });
/**
 * chacha20 RFC 8439 (IETF / TLS). 12-byte nonce, 4-byte counter.
 */
export const chacha20 = salsaBasic({
    core: chachaCore,
    counterRight: false,
    counterLen: 4,
    allow128bitKeys: false,
});
/**
 * xchacha20 eXtended-nonce. https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-xchacha
 */
export const xchacha20 = salsaBasic({
    core: chachaCore,
    counterRight: false,
    counterLen: 8,
    extendNonceFn: hchacha,
    allow128bitKeys: false,
});
/**
 * 8-round chacha from the original paper.
 */
export const chacha8 = salsaBasic({
    core: chachaCore,
    counterRight: false,
    counterLen: 4,
    rounds: 8,
});
/**
 * 12-round chacha from the original paper.
 */
export const chacha12 = salsaBasic({
    core: chachaCore,
    counterRight: false,
    counterLen: 4,
    rounds: 12,
});
const POW_2_130_5 = 2n ** 130n - 5n;
const POW_2_128_1 = 2n ** (16n * 8n) - 1n;
// Can be speed-up using BigUint64Array, but would be more complicated
export function poly1305(msg, key) {
    u.ensureBytes(msg);
    u.ensureBytes(key);
    let acc = 0n;
    const r = bytesToNumberLE(key.subarray(0, 16)) & 0x0ffffffc0ffffffc0ffffffc0fffffffn;
    const s = bytesToNumberLE(key.subarray(16));
    // Process by 16 byte chunks
    for (let i = 0; i < msg.length; i += 16) {
        const m = msg.subarray(i, i + 16);
        const n = bytesToNumberLE(m) | (1n << BigInt(8 * m.length));
        acc = ((acc + n) * r) % POW_2_130_5;
    }
    const res = (acc + s) & POW_2_128_1;
    return numberToBytesLE(res, 16);
}
function computeTag(fn, key, nonce, ciphertext, AAD) {
    const res = [];
    if (AAD) {
        res.push(AAD);
        const leftover = AAD.length % 16;
        if (leftover > 0)
            res.push(new Uint8Array(16 - leftover));
    }
    res.push(ciphertext);
    const leftover = ciphertext.length % 16;
    if (leftover > 0)
        res.push(new Uint8Array(16 - leftover));
    // Lengths
    const num = new Uint8Array(16);
    const view = u.createView(num);
    u.setBigUint64(view, 0, BigInt(AAD ? AAD.length : 0), true);
    u.setBigUint64(view, 8, BigInt(ciphertext.length), true);
    res.push(num);
    const authKey = fn(key, nonce, new Uint8Array(32));
    return poly1305(u.concatBytes(...res), authKey);
}
/**
 * xsalsa20-poly1305 eXtended-nonce (24 bytes) salsa.
 */
export function xsalsa20poly1305(key, nonce) {
    u.ensureBytes(key);
    u.ensureBytes(nonce);
    return {
        encrypt: (plaintext) => {
            u.ensureBytes(plaintext);
            const m = u.concatBytes(new Uint8Array(32), plaintext);
            const c = xsalsa20(key, nonce, m);
            const authKey = c.subarray(0, 32);
            const data = c.subarray(32);
            const tag = poly1305(data, authKey);
            return u.concatBytes(tag, data);
        },
        decrypt: (ciphertext) => {
            u.ensureBytes(ciphertext);
            if (ciphertext.length < 16)
                throw new Error('encrypted data must be at least 16 bytes');
            const c = u.concatBytes(new Uint8Array(16), ciphertext);
            const authKey = xsalsa20(key, nonce, new Uint8Array(32));
            const tag = poly1305(c.subarray(32), authKey);
            if (!u.equalBytes(c.subarray(16, 32), tag))
                throw new Error('invalid poly1305 tag');
            return xsalsa20(key, nonce, c).subarray(32);
        },
    };
}
/**
 * Alias to xsalsa20-poly1305
 */
export function secretbox(key, nonce) {
    u.ensureBytes(key);
    u.ensureBytes(nonce);
    const xs = xsalsa20poly1305(key, nonce);
    return { seal: xs.encrypt, open: xs.decrypt };
}
export const _poly1305_aead = (fn) => (key, nonce, AAD) => {
    const tagLength = 16;
    const keyLength = 32;
    u.ensureBytes(key, keyLength);
    u.ensureBytes(nonce);
    return {
        tagLength,
        encrypt: (plaintext) => {
            u.ensureBytes(plaintext);
            const res = fn(key, nonce, plaintext, undefined, 1);
            const tag = computeTag(fn, key, nonce, res, AAD);
            return u.concatBytes(res, tag);
        },
        decrypt: (ciphertext) => {
            u.ensureBytes(ciphertext);
            if (ciphertext.length < tagLength)
                throw new Error(`encrypted data must be at least ${tagLength} bytes`);
            const passedTag = ciphertext.subarray(-tagLength);
            const data = ciphertext.subarray(0, -tagLength);
            const tag = computeTag(fn, key, nonce, data, AAD);
            if (!u.equalBytes(passedTag, tag))
                throw new Error('invalid poly1305 tag');
            return fn(key, nonce, data, undefined, 1);
        },
    };
};
/**
 * chacha20-poly1305 12-byte-nonce chacha.
 */
export const chacha20poly1305 = _poly1305_aead(chacha20);
/**
 * xchacha20-poly1305 eXtended-nonce (24 bytes) chacha.
 * With 24-byte nonce, it's safe to use fill it with random (CSPRNG).
 */
export const xchacha20poly1305 = _poly1305_aead(xchacha20);
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