87 lines
2.5 KiB
Plaintext
87 lines
2.5 KiB
Plaintext
import { SHA2 } from './_sha2.js';
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import { wrapConstructor } from './utils.js';
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// SHA1 was cryptographically broken.
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// It is still widely used in legacy apps. Don't use it for a new protocol.
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// RFC 3174
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const rotl = (word: number, shift: number) => (word << shift) | ((word >>> (32 - shift)) >>> 0);
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// Choice: a ? b : c
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const Chi = (a: number, b: number, c: number) => (a & b) ^ (~a & c);
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// Majority function, true if any two inpust is true
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const Maj = (a: number, b: number, c: number) => (a & b) ^ (a & c) ^ (b & c);
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// Initial state
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const IV = new Uint32Array([0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0]);
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// Temporary buffer, not used to store anything between runs
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// Named this way because it matches specification.
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const SHA1_W = new Uint32Array(80);
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class SHA1 extends SHA2<SHA1> {
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private A = IV[0] | 0;
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private B = IV[1] | 0;
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private C = IV[2] | 0;
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private D = IV[3] | 0;
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private E = IV[4] | 0;
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constructor() {
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super(64, 20, 8, false);
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}
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protected get(): [number, number, number, number, number] {
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const { A, B, C, D, E } = this;
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return [A, B, C, D, E];
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}
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protected set(A: number, B: number, C: number, D: number, E: number) {
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this.A = A | 0;
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this.B = B | 0;
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this.C = C | 0;
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this.D = D | 0;
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this.E = E | 0;
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}
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protected process(view: DataView, offset: number): void {
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for (let i = 0; i < 16; i++, offset += 4) SHA1_W[i] = view.getUint32(offset, false);
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for (let i = 16; i < 80; i++)
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SHA1_W[i] = rotl(SHA1_W[i - 3] ^ SHA1_W[i - 8] ^ SHA1_W[i - 14] ^ SHA1_W[i - 16], 1);
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// Compression function main loop, 80 rounds
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let { A, B, C, D, E } = this;
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for (let i = 0; i < 80; i++) {
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let F, K;
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if (i < 20) {
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F = Chi(B, C, D);
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K = 0x5a827999;
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} else if (i < 40) {
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F = B ^ C ^ D;
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K = 0x6ed9eba1;
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} else if (i < 60) {
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F = Maj(B, C, D);
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K = 0x8f1bbcdc;
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} else {
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F = B ^ C ^ D;
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K = 0xca62c1d6;
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}
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const T = (rotl(A, 5) + F + E + K + SHA1_W[i]) | 0;
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E = D;
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D = C;
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C = rotl(B, 30);
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B = A;
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A = T;
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}
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// Add the compressed chunk to the current hash value
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A = (A + this.A) | 0;
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B = (B + this.B) | 0;
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C = (C + this.C) | 0;
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D = (D + this.D) | 0;
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E = (E + this.E) | 0;
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this.set(A, B, C, D, E);
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}
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protected roundClean() {
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SHA1_W.fill(0);
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}
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destroy() {
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this.set(0, 0, 0, 0, 0);
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this.buffer.fill(0);
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}
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}
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export const sha1 = wrapConstructor(() => new SHA1());
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