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js实现sha1

2026-01-31 01:50:13JavaScript

SHA-1 简介

SHA-1（Secure Hash Algorithm 1）是一种哈希函数，用于生成160位的哈希值。虽然现在已被认为不够安全，但在某些场景仍有使用需求。

浏览器端实现

现代浏览器原生支持crypto API，可以直接计算SHA-1：

async function sha1(message) {
  const encoder = new TextEncoder();
  const data = encoder.encode(message);
  const hashBuffer = await crypto.subtle.digest('SHA-1', data);
  const hashArray = Array.from(new Uint8Array(hashBuffer));
  const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
  return hashHex;
}

// 使用示例
sha1('hello world').then(console.log);  // 输出: 2aae6c35c94fcfb415dbe95f408b9ce91ee846ed

Node.js 实现

Node.js内置crypto模块：

const crypto = require('crypto');

function sha1(str) {
  return crypto.createHash('sha1').update(str).digest('hex');
}

console.log(sha1('hello world'));  // 输出: 2aae6c35c94fcfb415dbe95f408b9ce91ee846ed

纯JavaScript实现

以下是一个完整的SHA-1算法实现（不依赖任何库）：

function sha1(message) {
  function rotateLeft(n, s) {
    return (n << s) | (n >>> (32 - s));
  }

  function toHex(value) {
    let hex = '';
    for (let i = 7; i >= 0; i--) {
      hex += ((value >> (i * 4)) & 0xf).toString(16);
    }
    return hex;
  }

  const H = [0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0];
  const K = [0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6];

  message = unescape(encodeURIComponent(message));
  const length = message.length;
  const words = [];

  for (let i = 0; i < length - 3; i += 4) {
    words.push(
      message.charCodeAt(i) << 24 |
      message.charCodeAt(i + 1) << 16 |
      message.charCodeAt(i + 2) << 8 |
      message.charCodeAt(i + 3)
    );
  }

  switch (length % 4) {
    case 0: i = 0x080000000; break;
    case 1: i = message.charCodeAt(length - 1) << 24 | 0x0800000; break;
    case 2: i = message.charCodeAt(length - 2) << 24 | message.charCodeAt(length - 1) << 16 | 0x08000; break;
    case 3: i = message.charCodeAt(length - 3) << 24 | message.charCodeAt(length - 2) << 16 | message.charCodeAt(length - 1) << 8 | 0x80; break;
  }
  words.push(i);

  while (words.length % 16 !== 14) {
    words.push(0);
  }

  words.push(length >>> 29);
  words.push((length << 3) & 0x0ffffffff);

  for (let block = 0; block < words.length; block += 16) {
    const W = new Array(80);
    for (let t = 0; t < 16; t++) {
      W[t] = words[block + t];
    }
    for (let t = 16; t < 80; t++) {
      W[t] = rotateLeft(W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16], 1);
    }

    let [a, b, c, d, e] = H;

    for (let t = 0; t < 80; t++) {
      let s = Math.floor(t / 20);
      let f, k;

      switch (s) {
        case 0: f = (b & c) | (~b & d); k = K[0]; break;
        case 1: f = b ^ c ^ d; k = K[1]; break;
        case 2: f = (b & c) | (b & d) | (c & d); k = K[2]; break;
        case 3: f = b ^ c ^ d; k = K[3]; break;
      }

      const temp = (rotateLeft(a, 5) + f + e + k + W[t]) >>> 0;
      e = d;
      d = c;
      c = rotateLeft(b, 30);
      b = a;
      a = temp;
    }

    H[0] = (H[0] + a) >>> 0;
    H[1] = (H[1] + b) >>> 0;
    H[2] = (H[2] + c) >>> 0;
    H[3] = (H[3] + d) >>> 0;
    H[4] = (H[4] + e) >>> 0;
  }

  return H.map(toHex).join('').toLowerCase();
}

console.log(sha1('hello world'));  // 输出: 2aae6c35c94fcfb415dbe95f408b9ce91ee846ed