PHP的`hex2bin`的Node.js / JS实现返回错误的结果。 如何得到相同的结果？

这是一个PHP代码：

$h = hex2bin('db6dc3f86800da4f7c19e643e8941ebb'); $md5 = md5($h); echo $md5; // ==> b885730327999e8823d113161c3538d3 

这在Node.js中是一样的。 但结果是不同的：

 let h = hex2bin('db6dc3f86800da4f7c19e643e8941ebb'); let md5 = crypto.createHash('md5').update(h).digest('hex'); console.log(md5); ==> // a141519bf4b0acf2221ed94e721ddc7d 

我已经使用了互联网上可以find的hex2bin的JS类似物的四种不同的变体。 他们都不像PHP那样返回。 但更重要的是，这些JS函数都没有返回与其他JS函数相同的结果。

1. 从这里http://locutus.io/php/strings/hex2bin/
2. 从这个答案https://stackoverflow.com/a/12987042/1114926
3. 从这个答案https://stackoverflow.com/a/41550641/1114926
4. 从这个答案https://stackoverflow.com/a/17224848/1114926

为什么这样？ 在JS / Node.js中使用PHP的hex2bin真的不可能吗？ 我是否需要为这个function设置整个PHP解释器？

Answer 1

最后，经过一段时间的networking挖掘，我find了正确的解决scheme。 我认为这个问题出现在javascript的md5实现中，因为我在网上发现的大多数hex2bin javascript函数总是返回相同的结果。

我在这里find了这个MD5的 javascript实现。 正如你所看到的， hex2bin实现很短，你可以在很多地方find它。

 /* MD5 IMPLEMENTATION */ var hex_chr = "0123456789abcdef"; function rhex(num) { str = ""; for (j = 0; j <= 3; j++) str += hex_chr.charAt((num >> (j * 8 + 4)) & 0x0F) + hex_chr.charAt((num >> (j * 8)) & 0x0F); return str; } /* * Convert a string to a sequence of 16-word blocks, stored as an array. * Append padding bits and the length, as described in the MD5 standard. */ function str2blks_MD5(str) { nblk = ((str.length + 8) >> 6) + 1; blks = new Array(nblk * 16); for (i = 0; i < nblk * 16; i++) blks[i] = 0; for (i = 0; i < str.length; i++) blks[i >> 2] |= str.charCodeAt(i) << ((i % 4) * 8); blks[i >> 2] |= 0x80 << ((i % 4) * 8); blks[nblk * 16 - 2] = str.length * 8; return blks; } /* * Add integers, wrapping at 2^32. This uses 16-bit operations internally * to work around bugs in some JS interpreters. */ function add(x, y) { var lsw = (x & 0xFFFF) + (y & 0xFFFF); var msw = (x >> 16) + (y >> 16) + (lsw >> 16); return (msw << 16) | (lsw & 0xFFFF); } /* * Bitwise rotate a 32-bit number to the left */ function rol(num, cnt) { return (num << cnt) | (num >>> (32 - cnt)); } /* * These functions implement the basic operation for each round of the * algorithm. */ function cmn(q, a, b, x, s, t) { return add(rol(add(add(a, q), add(x, t)), 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); } /* * Take a string and return the hex representation of its MD5. */ function calcMD5(str) { x = str2blks_MD5(str); a = 1732584193; b = -271733879; c = -1732584194; d = 271733878; for (i = 0; i < x.length; i += 16) { olda = a; oldb = b; oldc = c; oldd = d; a = ff(a, b, c, d, x[i + 0], 7, -680876936); d = ff(d, a, b, c, x[i + 1], 12, -389564586); c = ff(c, d, a, b, x[i + 2], 17, 606105819); b = ff(b, c, d, a, x[i + 3], 22, -1044525330); a = ff(a, b, c, d, x[i + 4], 7, -176418897); d = ff(d, a, b, c, x[i + 5], 12, 1200080426); c = ff(c, d, a, b, x[i + 6], 17, -1473231341); b = ff(b, c, d, a, x[i + 7], 22, -45705983); a = ff(a, b, c, d, x[i + 8], 7, 1770035416); d = ff(d, a, b, c, x[i + 9], 12, -1958414417); c = ff(c, d, a, b, x[i + 10], 17, -42063); b = ff(b, c, d, a, x[i + 11], 22, -1990404162); a = ff(a, b, c, d, x[i + 12], 7, 1804603682); d = ff(d, a, b, c, x[i + 13], 12, -40341101); c = ff(c, d, a, b, x[i + 14], 17, -1502002290); b = ff(b, c, d, a, x[i + 15], 22, 1236535329); a = gg(a, b, c, d, x[i + 1], 5, -165796510); d = gg(d, a, b, c, x[i + 6], 9, -1069501632); c = gg(c, d, a, b, x[i + 11], 14, 643717713); b = gg(b, c, d, a, x[i + 0], 20, -373897302); a = gg(a, b, c, d, x[i + 5], 5, -701558691); d = gg(d, a, b, c, x[i + 10], 9, 38016083); c = gg(c, d, a, b, x[i + 15], 14, -660478335); b = gg(b, c, d, a, x[i + 4], 20, -405537848); a = gg(a, b, c, d, x[i + 9], 5, 568446438); d = gg(d, a, b, c, x[i + 14], 9, -1019803690); c = gg(c, d, a, b, x[i + 3], 14, -187363961); b = gg(b, c, d, a, x[i + 8], 20, 1163531501); a = gg(a, b, c, d, x[i + 13], 5, -1444681467); d = gg(d, a, b, c, x[i + 2], 9, -51403784); c = gg(c, d, a, b, x[i + 7], 14, 1735328473); b = gg(b, c, d, a, x[i + 12], 20, -1926607734); a = hh(a, b, c, d, x[i + 5], 4, -378558); d = hh(d, a, b, c, x[i + 8], 11, -2022574463); c = hh(c, d, a, b, x[i + 11], 16, 1839030562); b = hh(b, c, d, a, x[i + 14], 23, -35309556); a = hh(a, b, c, d, x[i + 1], 4, -1530992060); d = hh(d, a, b, c, x[i + 4], 11, 1272893353); c = hh(c, d, a, b, x[i + 7], 16, -155497632); b = hh(b, c, d, a, x[i + 10], 23, -1094730640); a = hh(a, b, c, d, x[i + 13], 4, 681279174); d = hh(d, a, b, c, x[i + 0], 11, -358537222); c = hh(c, d, a, b, x[i + 3], 16, -722521979); b = hh(b, c, d, a, x[i + 6], 23, 76029189); a = hh(a, b, c, d, x[i + 9], 4, -640364487); d = hh(d, a, b, c, x[i + 12], 11, -421815835); c = hh(c, d, a, b, x[i + 15], 16, 530742520); b = hh(b, c, d, a, x[i + 2], 23, -995338651); a = ii(a, b, c, d, x[i + 0], 6, -198630844); d = ii(d, a, b, c, x[i + 7], 10, 1126891415); c = ii(c, d, a, b, x[i + 14], 15, -1416354905); b = ii(b, c, d, a, x[i + 5], 21, -57434055); a = ii(a, b, c, d, x[i + 12], 6, 1700485571); d = ii(d, a, b, c, x[i + 3], 10, -1894986606); c = ii(c, d, a, b, x[i + 10], 15, -1051523); b = ii(b, c, d, a, x[i + 1], 21, -2054922799); a = ii(a, b, c, d, x[i + 8], 6, 1873313359); d = ii(d, a, b, c, x[i + 15], 10, -30611744); c = ii(c, d, a, b, x[i + 6], 15, -1560198380); b = ii(b, c, d, a, x[i + 13], 21, 1309151649); a = ii(a, b, c, d, x[i + 4], 6, -145523070); d = ii(d, a, b, c, x[i + 11], 10, -1120210379); c = ii(c, d, a, b, x[i + 2], 15, 718787259); b = ii(b, c, d, a, x[i + 9], 21, -343485551); a = add(a, olda); b = add(b, oldb); c = add(c, oldc); d = add(d, oldd); } return rhex(a) + rhex(b) + rhex(c) + rhex(d); } /* HEX2BIN IMPLEMENTATION */ function hex2bin(hex) { var bytes = [], str; for (var i = 0; i < hex.length - 1; i += 2) bytes.push(parseInt(hex.substr(i, 2), 16)); return String.fromCharCode.apply(String, bytes); } var inputStr = 'db6dc3f86800da4f7c19e643e8941ebb'; var hex2bin = hex2bin(inputStr); console.log('initial = ' + inputStr); console.log('hex2bin = ' + hex2bin); console.log('md5 = ' + calcMD5(hex2bin));