/**
 * GHash from AES-GCM and its little-endian "mirror image" Polyval from AES-SIV.
 *
 * Implemented in terms of GHash with conversion function for keys
 * GCM GHASH from
 * {@link https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf | NIST SP800-38d},
 * SIV from
 * {@link https://www.rfc-editor.org/rfc/rfc8452 | RFC 8452}.
 *
 * GHASH   modulo: x^128 + x^7   + x^2   + x     + 1
 * POLYVAL modulo: x^128 + x^127 + x^126 + x^121 + 1
 *
 * @module
 */
import { abytes, aexists, aoutput, clean, copyBytes, createView, swap32IfBE, swap8IfBE, u32, wrapMacConstructor, } from "./utils.js";
const BLOCK_SIZE = 16;
// TODO: rewrite
// temporary padding buffer
// ZEROS32 aliases these bytes, so clean(ZEROS32) also resets this shared tail-padding scratch.
const ZEROS16 = /* @__PURE__ */ new Uint8Array(16);
const ZEROS32 = /* @__PURE__ */ u32(ZEROS16);
// GHASH reduces modulo x^128 + x^7 + x^2 + x + 1, so the low-degree terms
// x^7 + x^2 + x + 1 become bits `11100001` = 0xe1 in R = 0xe1 || 0^120.
const POLY = 0xe1;
// v = 2*v % POLY
// NOTE: because x + x = 0 (add/sub is same), mul2(x) != x+x
// Montgomery ladder can multiply any field element with this doubling step;
// addition stays simple xor.
const mul2 = (s0, s1, s2, s3) => {
    const hiBit = s3 & 1;
    return {
        s3: (s2 << 31) | (s3 >>> 1),
        s2: (s1 << 31) | (s2 >>> 1),
        s1: (s0 << 31) | (s1 >>> 1),
        // NIST SP 800-38D §6.3 applies `V >> 1` and XORs R on carry. In this
        // 4x32-bit split, R = 0xe1 || 0^120 lives in the top byte of s0.
        s0: (s0 >>> 1) ^ ((POLY << 24) & -(hiBit & 1)), // reduce % poly
    };
};
// Per-word part of RFC 8452 `ByteReverse`; callers also reverse the 32-bit word order.
const swapLE = (n) => (((n >>> 0) & 0xff) << 24) |
    (((n >>> 8) & 0xff) << 16) |
    (((n >>> 16) & 0xff) << 8) |
    ((n >>> 24) & 0xff) |
    0;
// POLYVAL first applies RFC 8452's per-word byte reversal, then re-normalizes
// host-endian u32 loads to the little-endian word value `_updateBlock()` expects.
const swap8IfLE = (n) => swap8IfBE(swapLE(n));
/**
 * `mulX_GHASH(ByteReverse(H))` from RFC 8452 Appendix A.
 * @param k mutated in place
 */
export function _toGHASHKey(k) {
    // The input is the original POLYVAL key H; reverse() materializes
    // RFC 8452's `ByteReverse(H)` before the GHASH mulX step.
    k.reverse();
    const hiBit = k[15] & 1;
    // k >>= 1
    let carry = 0;
    for (let i = 0; i < k.length; i++) {
        const t = k[i];
        k[i] = (t >>> 1) | carry;
        carry = (t & 1) << 7;
    }
    k[0] ^= -hiBit & 0xe1; // if (hiBit) n ^= 0xe1000000000000000000000000000000;
    return k;
}
// Precompute-window heuristic only: larger inputs trade memory for fewer table lookups.
// Any caller-provided length hint still collapses to one of the supported windows {2, 4, 8}.
const estimateWindow = (bytes) => {
    if (bytes > 64 * 1024)
        return 8;
    if (bytes > 1024)
        return 4;
    return 2;
};
/**
 * Incremental GHASH state for AES-GCM.
 * @param key - 16-byte GHASH key.
 * @param expectedLength - Expected message length for table sizing.
 * Chunking is segment-based, not hash-streaming: every `update()` call is zero-padded
 * to the next 16-byte boundary before it is absorbed. This matches the internal AES/GCM
 * use where AAD, payload, and length block are separate padded segments.
 * @example
 * Feeds one ciphertext block into an incremental GHASH state with a fresh hash key.
 *
 * ```ts
 * import { GHASH } from '@noble/ciphers/_polyval.js';
 * import { randomBytes } from '@noble/ciphers/utils.js';
 * const key = randomBytes(16);
 * const mac = new GHASH(key);
 * mac.update(new Uint8Array(16));
 * mac.digest();
 * ```
 */
export class GHASH {
    blockLen = BLOCK_SIZE;
    outputLen = BLOCK_SIZE;
    s0 = 0;
    s1 = 0;
    s2 = 0;
    s3 = 0;
    finished = false;
    destroyed = false;
    t;
    W;
    windowSize;
    // We select bits per window adaptively based on expectedLength
    constructor(key, expectedLength) {
        abytes(key, 16, 'key');
        key = copyBytes(key);
        const kView = createView(key);
        let k0 = kView.getUint32(0, false);
        let k1 = kView.getUint32(4, false);
        let k2 = kView.getUint32(8, false);
        let k3 = kView.getUint32(12, false);
        // generate table of doubled keys (half of montgomery ladder)
        const doubles = [];
        for (let i = 0; i < 128; i++) {
            doubles.push({ s0: swapLE(k0), s1: swapLE(k1), s2: swapLE(k2), s3: swapLE(k3) });
            ({ s0: k0, s1: k1, s2: k2, s3: k3 } = mul2(k0, k1, k2, k3));
        }
        const W = estimateWindow(expectedLength || 1024);
        if (![1, 2, 4, 8].includes(W))
            throw new Error('ghash: invalid window size, expected 2, 4 or 8');
        this.W = W;
        const bits = 128; // always 128 bits;
        const windows = bits / W;
        const windowSize = (this.windowSize = 2 ** W);
        const items = [];
        // Create precompute table for window of W bits
        for (let w = 0; w < windows; w++) {
            // truth table: 00, 01, 10, 11
            for (let byte = 0; byte < windowSize; byte++) {
                // prettier-ignore
                let s0 = 0, s1 = 0, s2 = 0, s3 = 0;
                for (let j = 0; j < W; j++) {
                    const bit = (byte >>> (W - j - 1)) & 1;
                    if (!bit)
                        continue;
                    const { s0: d0, s1: d1, s2: d2, s3: d3 } = doubles[W * w + j];
                    ((s0 ^= d0), (s1 ^= d1), (s2 ^= d2), (s3 ^= d3));
                }
                items.push({ s0, s1, s2, s3 });
            }
        }
        this.t = items;
    }
    _updateBlock(s0, s1, s2, s3) {
        ((s0 ^= this.s0), (s1 ^= this.s1), (s2 ^= this.s2), (s3 ^= this.s3));
        const { W, t, windowSize } = this;
        // prettier-ignore
        let o0 = 0, o1 = 0, o2 = 0, o3 = 0;
        const mask = (1 << W) - 1; // 2**W will kill performance.
        let w = 0;
        // NIST SP 800-38D §6.3 interprets blocks as little-endian polynomials,
        // so the lookup walk consumes each word byte-by-byte from
        // least-significant to most-significant bits.
        for (const num of [s0, s1, s2, s3]) {
            for (let bytePos = 0; bytePos < 4; bytePos++) {
                const byte = (num >>> (8 * bytePos)) & 0xff;
                for (let bitPos = 8 / W - 1; bitPos >= 0; bitPos--) {
                    const bit = (byte >>> (W * bitPos)) & mask;
                    const { s0: e0, s1: e1, s2: e2, s3: e3 } = t[w * windowSize + bit];
                    ((o0 ^= e0), (o1 ^= e1), (o2 ^= e2), (o3 ^= e3));
                    w += 1;
                }
            }
        }
        this.s0 = o0;
        this.s1 = o1;
        this.s2 = o2;
        this.s3 = o3;
    }
    update(data) {
        aexists(this);
        abytes(data);
        data = copyBytes(data);
        const b32 = u32(data);
        const blocks = Math.floor(data.length / BLOCK_SIZE);
        const left = data.length % BLOCK_SIZE;
        for (let i = 0; i < blocks; i++) {
            this._updateBlock(swap8IfBE(b32[i * 4 + 0]), swap8IfBE(b32[i * 4 + 1]), swap8IfBE(b32[i * 4 + 2]), swap8IfBE(b32[i * 4 + 3]));
        }
        if (left) {
            ZEROS16.set(data.subarray(blocks * BLOCK_SIZE));
            // Tail blocks go through the shared ZEROS32 scratch, so they need the same host-endian
            // normalization as full blocks; otherwise segmented GHASH/POLYVAL updates diverge on BE.
            this._updateBlock(swap8IfBE(ZEROS32[0]), swap8IfBE(ZEROS32[1]), swap8IfBE(ZEROS32[2]), swap8IfBE(ZEROS32[3]));
            clean(ZEROS32); // clean tmp buffer
        }
        return this;
    }
    destroy() {
        // `aexists(this)` guards update/digest paths, so destroy must mark the instance unusable too.
        this.destroyed = true;
        const { t } = this;
        // Wipe the key-derived precompute table; scalar accumulator words remain,
        // but the destroyed guard blocks further use.
        // clean precompute table
        for (const elm of t) {
            ((elm.s0 = 0), (elm.s1 = 0), (elm.s2 = 0), (elm.s3 = 0));
        }
    }
    digestInto(out) {
        aexists(this);
        // `digestInto(out)` is the no-allocation fast path, so callers must pass a
        // 32-bit-aligned buffer before we reinterpret it with `u32(out)`.
        aoutput(out, this, true);
        this.finished = true;
        // NIST SP 800-38D §6.4 returns the final 128-bit block Y_m.
        // `digestInto()` follows the relaxed `aoutput()` contract, so only
        // out[0..15] may be touched.
        const { s0, s1, s2, s3 } = this;
        const o32 = u32(out);
        o32[0] = s0;
        o32[1] = s1;
        o32[2] = s2;
        o32[3] = s3;
        swap32IfBE(o32);
    }
    digest() {
        const res = new Uint8Array(BLOCK_SIZE);
        this.digestInto(res);
        // `res` is independent of internal state, so it stays valid after destroy() wipes the table.
        this.destroy();
        return res;
    }
}
/**
 * Incremental POLYVAL state for AES-SIV.
 * @param key - 16-byte POLYVAL key.
 * @param expectedLength - Expected message length for table sizing.
 * Inherits GHASH's segment-padded `update()` behavior: each call is padded
 * independently to a 16-byte boundary before absorption.
 * @example
 * Feeds one block into an incremental POLYVAL state with a fresh hash key.
 *
 * ```ts
 * import { Polyval } from '@noble/ciphers/_polyval.js';
 * import { randomBytes } from '@noble/ciphers/utils.js';
 * const key = randomBytes(16);
 * const mac = new Polyval(key);
 * mac.update(new Uint8Array(16));
 * mac.digest();
 * ```
 */
export class Polyval extends GHASH {
    constructor(key, expectedLength) {
        abytes(key);
        // RFC 8452 Appendix A converts the POLYVAL key with
        // `mulX_GHASH(ByteReverse(H))`; copy first because `_toGHASHKey(...)`
        // mutates in place.
        const ghKey = _toGHASHKey(copyBytes(key));
        super(ghKey, expectedLength);
        clean(ghKey);
    }
    update(data) {
        aexists(this);
        abytes(data);
        data = copyBytes(data);
        const b32 = u32(data);
        const left = data.length % BLOCK_SIZE;
        const blocks = Math.floor(data.length / BLOCK_SIZE);
        for (let i = 0; i < blocks; i++) {
            // RFC 8452 Appendix A feeds `ByteReverse(X_i)` into GHASH, so POLYVAL
            // reverses the 32-bit word order in addition to the per-word byte swap.
            this._updateBlock(swap8IfLE(b32[i * 4 + 3]), swap8IfLE(b32[i * 4 + 2]), swap8IfLE(b32[i * 4 + 1]), swap8IfLE(b32[i * 4 + 0]));
        }
        if (left) {
            ZEROS16.set(data.subarray(blocks * BLOCK_SIZE));
            this._updateBlock(swap8IfLE(ZEROS32[3]), swap8IfLE(ZEROS32[2]), swap8IfLE(ZEROS32[1]), swap8IfLE(ZEROS32[0]));
            clean(ZEROS32);
        }
        return this;
    }
    digestInto(out) {
        aexists(this);
        // `digestInto(out)` is the no-allocation fast path, so callers must pass a
        // 32-bit-aligned buffer before we reinterpret the output prefix with `u32(view)`.
        aoutput(out, this, true);
        this.finished = true;
        // RFC 8452 Appendix A maps POLYVAL output back through `ByteReverse(...)`.
        // `digestInto()` follows the relaxed `aoutput()` contract, so only out[0..15] may be touched.
        const view = out.subarray(0, this.outputLen);
        const { s0, s1, s2, s3 } = this;
        const o32 = u32(view);
        o32[0] = s0;
        o32[1] = s1;
        o32[2] = s2;
        o32[3] = s3;
        swap32IfBE(o32);
        view.reverse();
    }
}
/**
 * GHash MAC for AES-GCM.
 * @param msg - Message bytes to authenticate.
 * @param key - 16-byte GHASH key.
 * @returns 16-byte authentication tag.
 * @example
 * Authenticates a short message with GHASH and a fresh hash key.
 *
 * ```ts
 * import { ghash } from '@noble/ciphers/_polyval.js';
 * import { randomBytes } from '@noble/ciphers/utils.js';
 * const key = randomBytes(16);
 * ghash(new Uint8Array(), key);
 * ```
 */
export const ghash = 
/* @__PURE__ */ wrapMacConstructor(16, (key, expectedLength) => new GHASH(key, expectedLength), (msg) => [msg.length]);
/**
 * POLYVAL MAC for AES-SIV.
 * @param msg - Message bytes to authenticate.
 * @param key - 16-byte POLYVAL key.
 * @returns 16-byte authentication tag.
 * @example
 * Authenticates a short message with POLYVAL and a fresh hash key.
 *
 * ```ts
 * import { polyval } from '@noble/ciphers/_polyval.js';
 * import { randomBytes } from '@noble/ciphers/utils.js';
 * const key = randomBytes(16);
 * polyval(new Uint8Array(), key);
 * ```
 */
export const polyval = 
/* @__PURE__ */ wrapMacConstructor(16, (key, expectedLength) => new Polyval(key, expectedLength), (msg) => [msg.length]);
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