/**
* Internal Merkle-Damgard hash utils.
* @module
*/
import { abytes, aexists, aoutput, clean, createView, } from "./utils.js";
/**
* Shared 32-bit conditional boolean primitive reused by SHA-256, SHA-1, and MD5 `F`.
* Returns bits from `b` when `a` is set, otherwise from `c`.
* The XOR form is equivalent to MD5's `F(X,Y,Z) = XY v not(X)Z` because the masked terms never
* set the same bit.
* @param a - selector word
* @param b - word chosen when selector bit is set
* @param c - word chosen when selector bit is clear
* @returns Mixed 32-bit word.
* @example
* Combine three words with the shared 32-bit choice primitive.
* ```ts
* Chi(0xffffffff, 0x12345678, 0x87654321);
* ```
*/
export function Chi(a, b, c) {
return (a & b) ^ (~a & c);
}
/**
* Shared 32-bit majority primitive reused by SHA-256 and SHA-1.
* Returns bits shared by at least two inputs.
* @param a - first input word
* @param b - second input word
* @param c - third input word
* @returns Mixed 32-bit word.
* @example
* Combine three words with the shared 32-bit majority primitive.
* ```ts
* Maj(0xffffffff, 0x12345678, 0x87654321);
* ```
*/
export function Maj(a, b, c) {
return (a & b) ^ (a & c) ^ (b & c);
}
/**
* Merkle-Damgard hash construction base class.
* Could be used to create MD5, RIPEMD, SHA1, SHA2.
* Accepts only byte-aligned `Uint8Array` input, even when the underlying spec describes bit
* strings with partial-byte tails.
* @param blockLen - internal block size in bytes
* @param outputLen - digest size in bytes
* @param padOffset - trailing length field size in bytes
* @param isLE - whether length and state words are encoded in little-endian
* @example
* Use a concrete subclass to get the shared Merkle-Damgard update/digest flow.
* ```ts
* import { _SHA1 } from '@noble/hashes/legacy.js';
* const hash = new _SHA1();
* hash.update(new Uint8Array([97, 98, 99]));
* hash.digest();
* ```
*/
export class HashMD {
blockLen;
outputLen;
canXOF = false;
padOffset;
isLE;
// For partial updates less than block size
buffer;
view;
finished = false;
length = 0;
pos = 0;
destroyed = false;
constructor(blockLen, outputLen, padOffset, isLE) {
this.blockLen = blockLen;
this.outputLen = outputLen;
this.padOffset = padOffset;
this.isLE = isLE;
this.buffer = new Uint8Array(blockLen);
this.view = createView(this.buffer);
}
update(data) {
aexists(this);
abytes(data);
const { view, buffer, blockLen } = this;
const len = data.length;
for (let pos = 0; pos < len;) {
const take = Math.min(blockLen - this.pos, len - pos);
// Fast path only when there is no buffered partial block: `take === blockLen` implies
// `this.pos === 0`, so we can process full blocks directly from the input view.
if (take === blockLen) {
const dataView = createView(data);
for (; blockLen <= len - pos; pos += blockLen)
this.process(dataView, pos);
continue;
}
buffer.set(data.subarray(pos, pos + take), this.pos);
this.pos += take;
pos += take;
if (this.pos === blockLen) {
this.process(view, 0);
this.pos = 0;
}
}
this.length += data.length;
this.roundClean();
return this;
}
digestInto(out) {
aexists(this);
aoutput(out, this);
this.finished = true;
// Padding
// We can avoid allocation of buffer for padding completely if it
// was previously not allocated here. But it won't change performance.
const { buffer, view, blockLen, isLE } = this;
let { pos } = this;
// append the bit '1' to the message
buffer[pos++] = 0b10000000;
clean(this.buffer.subarray(pos));
// we have less than padOffset left in buffer, so we cannot put length in
// current block, need process it and pad again
if (this.padOffset > blockLen - pos) {
this.process(view, 0);
pos = 0;
}
// Pad until full block byte with zeros
for (let i = pos; i < blockLen; i++)
buffer[i] = 0;
// `padOffset` reserves the whole length field. For SHA-384/512 the high 64 bits stay zero from
// the padding fill above, and JS will overflow before user input can make that half non-zero.
// So we only need to write the low 64 bits here.
view.setBigUint64(blockLen - 8, BigInt(this.length * 8), isLE);
this.process(view, 0);
const oview = createView(out);
const len = this.outputLen;
// NOTE: we do division by 4 later, which must be fused in single op with modulo by JIT
if (len % 4)
throw new Error('_sha2: outputLen must be aligned to 32bit');
const outLen = len / 4;
const state = this.get();
if (outLen > state.length)
throw new Error('_sha2: outputLen bigger than state');
for (let i = 0; i < outLen; i++)
oview.setUint32(4 * i, state[i], isLE);
}
digest() {
const { buffer, outputLen } = this;
this.digestInto(buffer);
// Copy before destroy(): subclasses wipe `buffer` during cleanup, but `digest()` must return
// fresh bytes to the caller.
const res = buffer.slice(0, outputLen);
this.destroy();
return res;
}
_cloneInto(to) {
to ||= new this.constructor();
to.set(...this.get());
const { blockLen, buffer, length, finished, destroyed, pos } = this;
to.destroyed = destroyed;
to.finished = finished;
to.length = length;
to.pos = pos;
// Only partial-block bytes need copying: when `length % blockLen === 0`, `pos === 0` and
// later `update()` / `digestInto()` overwrite `to.buffer` from the start before reading it.
if (length % blockLen)
to.buffer.set(buffer);
return to;
}
clone() {
return this._cloneInto();
}
}
/**
* Initial SHA-2 state: fractional parts of square roots of first 16 primes 2..53.
* Check out `test/misc/sha2-gen-iv.js` for recomputation guide.
*/
/** Initial SHA256 state from RFC 6234 §6.1: the first 32 bits of the fractional parts of the
* square roots of the first eight prime numbers. Exported as a shared table; callers must treat
* it as read-only because constructors copy words from it by index. */
export const SHA256_IV = /* @__PURE__ */ Uint32Array.from([
0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19,
]);
/** Initial SHA224 state `H(0)` from RFC 6234 §6.1. Exported as a shared table; callers must
* treat it as read-only because constructors copy words from it by index. */
export const SHA224_IV = /* @__PURE__ */ Uint32Array.from([
0xc1059ed8, 0x367cd507, 0x3070dd17, 0xf70e5939, 0xffc00b31, 0x68581511, 0x64f98fa7, 0xbefa4fa4,
]);
/** Initial SHA384 state from RFC 6234 §6.3: eight RFC 64-bit `H(0)` words stored as sixteen
* big-endian 32-bit halves. Derived from the fractional parts of the square roots of the ninth
* through sixteenth prime numbers. Exported as a shared table; callers must treat it as read-only
* because constructors copy halves from it by index. */
export const SHA384_IV = /* @__PURE__ */ Uint32Array.from([
0xcbbb9d5d, 0xc1059ed8, 0x629a292a, 0x367cd507, 0x9159015a, 0x3070dd17, 0x152fecd8, 0xf70e5939,
0x67332667, 0xffc00b31, 0x8eb44a87, 0x68581511, 0xdb0c2e0d, 0x64f98fa7, 0x47b5481d, 0xbefa4fa4,
]);
/** Initial SHA512 state from RFC 6234 §6.3: eight RFC 64-bit `H(0)` words stored as sixteen
* big-endian 32-bit halves. Derived from the fractional parts of the square roots of the first
* eight prime numbers. Exported as a shared table; callers must treat it as read-only because
* constructors copy halves from it by index. */
export const SHA512_IV = /* @__PURE__ */ Uint32Array.from([
0x6a09e667, 0xf3bcc908, 0xbb67ae85, 0x84caa73b, 0x3c6ef372, 0xfe94f82b, 0xa54ff53a, 0x5f1d36f1,
0x510e527f, 0xade682d1, 0x9b05688c, 0x2b3e6c1f, 0x1f83d9ab, 0xfb41bd6b, 0x5be0cd19, 0x137e2179,
]);
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