为什么不试试http://phpjs.org/functions/md5/?

不幸的是，任何模拟脚本的性能都是有限的，但是这可以呈现真正的md5散列。尽管我建议不要使用md5作为密码，因为它是一个快速呈现的散列。

我找到了许多关于这个主题的文章。 他们都建议约瑟夫·迈耶斯实施。

在某些测试中，请参阅:http://jsperf.com/md5-shootout

在我对终极速度的追求中，我看了这段代码，我看到它可以改进。所以我基于Joseph Meyers代码创建了一个新的JS脚本。

参见改进的约瑟夫迈耶斯代码

MD5基准测试的获胜者是Javascript-MD5

在https://jsben.ch/imzpt上测试或查看 jsfiddle.net/w731ed58/

我只需要支持支持类型化数组(DataView, ArrayBuffer等)的HTML5浏览器。 我认为我采取了约瑟夫迈尔斯代码，并修改它，以支持传递在Uint8Array。我没有捕捉到所有的改进，仍然可能有一些char()数组构件可以改进。我需要它来添加到PouchDB项目。

var PouchUtils = {};
PouchUtils.Crypto = {};
(function () {
    PouchUtils.Crypto.MD5 = function (uint8Array) {
        function md5cycle(x, k) {
            var a = x[0], b = x[1], c = x[2], d = x[3];

            a = ff(a, b, c, d, k[0], 7, -680876936);
            d = ff(d, a, b, c, k[1], 12, -389564586);
            c = ff(c, d, a, b, k[2], 17, 606105819);
            b = ff(b, c, d, a, k[3], 22, -1044525330);
            a = ff(a, b, c, d, k[4], 7, -176418897);
            d = ff(d, a, b, c, k[5], 12, 1200080426);
            c = ff(c, d, a, b, k[6], 17, -1473231341);
            b = ff(b, c, d, a, k[7], 22, -45705983);
            a = ff(a, b, c, d, k[8], 7, 1770035416);
            d = ff(d, a, b, c, k[9], 12, -1958414417);
            c = ff(c, d, a, b, k[10], 17, -42063);
            b = ff(b, c, d, a, k[11], 22, -1990404162);
            a = ff(a, b, c, d, k[12], 7, 1804603682);
            d = ff(d, a, b, c, k[13], 12, -40341101);
            c = ff(c, d, a, b, k[14], 17, -1502002290);
            b = ff(b, c, d, a, k[15], 22, 1236535329);

            a = gg(a, b, c, d, k[1], 5, -165796510);
            d = gg(d, a, b, c, k[6], 9, -1069501632);
            c = gg(c, d, a, b, k[11], 14, 643717713);
            b = gg(b, c, d, a, k[0], 20, -373897302);
            a = gg(a, b, c, d, k[5], 5, -701558691);
            d = gg(d, a, b, c, k[10], 9, 38016083);
            c = gg(c, d, a, b, k[15], 14, -660478335);
            b = gg(b, c, d, a, k[4], 20, -405537848);
            a = gg(a, b, c, d, k[9], 5, 568446438);
            d = gg(d, a, b, c, k[14], 9, -1019803690);
            c = gg(c, d, a, b, k[3], 14, -187363961);
            b = gg(b, c, d, a, k[8], 20, 1163531501);
            a = gg(a, b, c, d, k[13], 5, -1444681467);
            d = gg(d, a, b, c, k[2], 9, -51403784);
            c = gg(c, d, a, b, k[7], 14, 1735328473);
            b = gg(b, c, d, a, k[12], 20, -1926607734);

            a = hh(a, b, c, d, k[5], 4, -378558);
            d = hh(d, a, b, c, k[8], 11, -2022574463);
            c = hh(c, d, a, b, k[11], 16, 1839030562);
            b = hh(b, c, d, a, k[14], 23, -35309556);
            a = hh(a, b, c, d, k[1], 4, -1530992060);
            d = hh(d, a, b, c, k[4], 11, 1272893353);
            c = hh(c, d, a, b, k[7], 16, -155497632);
            b = hh(b, c, d, a, k[10], 23, -1094730640);
            a = hh(a, b, c, d, k[13], 4, 681279174);
            d = hh(d, a, b, c, k[0], 11, -358537222);
            c = hh(c, d, a, b, k[3], 16, -722521979);
            b = hh(b, c, d, a, k[6], 23, 76029189);
            a = hh(a, b, c, d, k[9], 4, -640364487);
            d = hh(d, a, b, c, k[12], 11, -421815835);
            c = hh(c, d, a, b, k[15], 16, 530742520);
            b = hh(b, c, d, a, k[2], 23, -995338651);

            a = ii(a, b, c, d, k[0], 6, -198630844);
            d = ii(d, a, b, c, k[7], 10, 1126891415);
            c = ii(c, d, a, b, k[14], 15, -1416354905);
            b = ii(b, c, d, a, k[5], 21, -57434055);
            a = ii(a, b, c, d, k[12], 6, 1700485571);
            d = ii(d, a, b, c, k[3], 10, -1894986606);
            c = ii(c, d, a, b, k[10], 15, -1051523);
            b = ii(b, c, d, a, k[1], 21, -2054922799);
            a = ii(a, b, c, d, k[8], 6, 1873313359);
            d = ii(d, a, b, c, k[15], 10, -30611744);
            c = ii(c, d, a, b, k[6], 15, -1560198380);
            b = ii(b, c, d, a, k[13], 21, 1309151649);
            a = ii(a, b, c, d, k[4], 6, -145523070);
            d = ii(d, a, b, c, k[11], 10, -1120210379);
            c = ii(c, d, a, b, k[2], 15, 718787259);
            b = ii(b, c, d, a, k[9], 21, -343485551);

            x[0] = add32(a, x[0]);
            x[1] = add32(b, x[1]);
            x[2] = add32(c, x[2]);
            x[3] = add32(d, x[3]);

        }

        function cmn(q, a, b, x, s, t) {
            a = add32(add32(a, q), add32(x, t));
            return add32((a << s) | (a >>> (32 - s)), b);
        }

        function ff(a, b, c, d, x, s, t) {
            return cmn((b & c) | ((~b) & d), a, b, x, s, t);
        }

        function gg(a, b, c, d, x, s, t) {
            return cmn((b & d) | (c & (~d)), a, b, x, s, t);
        }

        function hh(a, b, c, d, x, s, t) {
            return cmn(b ^ c ^ d, a, b, x, s, t);
        }

        function ii(a, b, c, d, x, s, t) {
            return cmn(c ^ (b | (~d)), a, b, x, s, t);
        }

        function md51(s) {
            txt = '';
            var n = s.length,
            state = [1732584193, -271733879, -1732584194, 271733878], i;
            for (i = 64; i <= s.length; i += 64) {
                md5cycle(state, md5blk(s.subarray(i - 64, i)));
            }
            s = s.subarray(i - 64);
            var tail = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
            for (i = 0; i < s.length; i++)
                tail[i >> 2] |= s[i] << ((i % 4) << 3);
            tail[i >> 2] |= 0x80 << ((i % 4) << 3);
            if (i > 55) {
                md5cycle(state, tail);
                for (i = 0; i < 16; i++) tail[i] = 0;
            }
            tail[14] = n * 8;
            md5cycle(state, tail);
            return state;
        }

        /* there needs to be support for Unicode here,
         * unless we pretend that we can redefine the MD-5
         * algorithm for multi-byte characters (perhaps
         * by adding every four 16-bit characters and
         * shortening the sum to 32 bits). Otherwise
         * I suggest performing MD-5 as if every character
         * was two bytes--e.g., 0040 0025 = @%--but then
         * how will an ordinary MD-5 sum be matched?
         * There is no way to standardize text to something
         * like UTF-8 before transformation; speed cost is
         * utterly prohibitive. The JavaScript standard
         * itself needs to look at this: it should start
         * providing access to strings as preformed UTF-8
         * 8-bit unsigned value arrays.
         */
        function md5blk(s) { /* I figured global was faster.   */
            var md5blks = [], i; /* Andy King said do it this way. */
            for (i = 0; i < 64; i += 4) {
                md5blks[i >> 2] = s[i]
                + (s[i + 1] << 8)
                + (s[i + 2] << 16)
                + (s[i + 3] << 24);
            }
            return md5blks;
        }

        var hex_chr = '0123456789abcdef'.split('');

        function rhex(n) {
            var s = '', j = 0;
            for (; j < 4; j++)
                s += hex_chr[(n >> (j * 8 + 4)) & 0x0F]
                + hex_chr[(n >> (j * 8)) & 0x0F];
            return s;
        }

        function hex(x) {
            for (var i = 0; i < x.length; i++)
                x[i] = rhex(x[i]);
            return x.join('');
        }

        function md5(s) {
            return hex(md51(s));
        }

        function add32(a, b) {
            return (a + b) & 0xFFFFFFFF;
        }

        return md5(uint8Array);
    };
})();

令我烦恼的是，我找不到一个既快速又支持Unicode字符串的实现。

所以我做了一个支持Unicode字符串的实现，并且仍然比目前最快的ascii-only-strings实现更快(在编写时):

https://github.com/gorhill/yamd5.js

基于Joseph Myers的代码，但使用了TypedArrays，并进行了其他改进。

Node.js有内置的支持

const crypto = require('crypto')
crypto.createHash('md5').update('hello world').digest('hex')

上面的代码段为字符串hello world计算MD5十六进制字符串

这种解决方案的优点是不需要安装额外的库。

我认为内置解决方案应该是最快的。如果不是，我们应该为Node.js项目创建issue/PR。