【字符编码系列】MD5与SHA-1

(function(exports) {
    "use strict";
    /**
     * 决定hex是大写散列还是小写散列
     * 为true为大写
     */
    var hexcase = 0;
    var b64pad = "";
    var chrsz = 8;
    /**
     * @description hex_sha1加密,据传是最安全的散列方法,不可逆
     * @param {String} s 加密内容
     * @return {String} 返回密文,hex字符串
     */
    exports.sha1_hex = function(s) {
        return binb2hex(core_sha1(str2binb(s), s.length * chrsz))
    };
    /**
     * @description b64_sha1加密,也是sha1加密的一种,不可逆
     * @param {String} s 加密内容
     * @return {String} 返回密文,base64字符串
     */
    exports.sha1_b64 = function(s) {
        return binb2b64(core_sha1(str2binb(s), s.length * chrsz))
    };
    /**
     * @description 普通字符串加密,也是sha1加密的一种,不可逆
     * @param {String} s 加密内容
     * @return {String} 返回密文,string字符串
     */
    exports.sha1_str = function(s) {
        return binb2str(core_sha1(str2binb(s), s.length * chrsz))
    };

    function hex_hmac_sha1(key, data) {
        return binb2hex(core_hmac_sha1(key, data))
    }

    function b64_hmac_sha1(key, data) {
        return binb2b64(core_hmac_sha1(key, data))
    }

    function str_hmac_sha1(key, data) {
        return binb2str(core_hmac_sha1(key, data))
    }

    function core_sha1(x, len) {
        x[len >> 5] |= 0x80 << (24 - len % 32);
        x[((len + 64 >> 9) << 4) + 15] = len;
        var w = Array(80);
        var a = 1732584193;
        var b = -271733879;
        var c = -1732584194;
        var d = 271733878;
        var e = -1009589776;
        for(var i = 0; i < x.length; i += 16) {
            var olda = a;
            var oldb = b;
            var oldc = c;
            var oldd = d;
            var olde = e;
            for(var j = 0; j < 80; j++) {
                if(j < 16) w[j] = x[i + j];
                else w[j] = rol(w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16], 1);
                var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)), safe_add(safe_add(e, w[j]), sha1_kt(j)));
                e = d;
                d = c;
                c = rol(b, 30);
                b = a;
                a = t
            }
            a = safe_add(a, olda);
            b = safe_add(b, oldb);
            c = safe_add(c, oldc);
            d = safe_add(d, oldd);
            e = safe_add(e, olde)
        }
        return Array(a, b, c, d, e)
    }

    function sha1_ft(t, b, c, d) {
        if(t < 20) return(b & c) | ((~b) & d);
        if(t < 40) return b ^ c ^ d;
        if(t < 60) return(b & c) | (b & d) | (c & d);
        return b ^ c ^ d
    }

    function sha1_kt(t) {
        return(t < 20) ? 1518500249 : (t < 40) ? 1859775393 : (t < 60) ? -1894007588 : -899497514
    }

    function core_hmac_sha1(key, data) {
        var bkey = str2binb(key);
        if(bkey.length > 16) bkey = core_sha1(bkey, key.length * chrsz);
        var ipad = Array(16),
            opad = Array(16);
        for(var i = 0; i < 16; i++) {
            ipad[i] = bkey[i] ^ 0x36363636;
            opad[i] = bkey[i] ^ 0x5C5C5C5C
        }
        var hash = core_sha1(ipad.concat(str2binb(data)), 512 + data.length * chrsz);
        return core_sha1(opad.concat(hash), 512 + 160)
    }

    function safe_add(x, y) {
        var lsw = (x & 0xFFFF) + (y & 0xFFFF);
        var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
        return(msw << 16) | (lsw & 0xFFFF)
    }

    function rol(num, cnt) {
        return(num << cnt) | (num >>> (32 - cnt))
    }

    function str2binb(str) {
        var bin = Array();
        var mask = (1 << chrsz) - 1;
        for(var i = 0; i < str.length * chrsz; i += chrsz) bin[i >> 5] |= (str.charCodeAt(i / chrsz) & mask) << (32 - chrsz - i % 32);
        return bin
    }

    function binb2str(bin) {
        var str = "";
        var mask = (1 << chrsz) - 1;
        for(var i = 0; i < bin.length * 32; i += chrsz) str += String.fromCharCode((bin[i >> 5] >>> (32 - chrsz - i % 32)) & mask);
        return str
    }

    function binb2hex(binarray) {
        var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
        var str = "";
        for(var i = 0; i < binarray.length * 4; i++) {
            str += hex_tab.charAt((binarray[i >> 2] >> ((3 - i % 4) * 8 + 4)) & 0xF) + hex_tab.charAt((binarray[i >> 2] >> ((3 - i % 4) * 8)) & 0xF)
        }
        return str
    }

    function binb2b64(binarray) {
        var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
        var str = "";
        for(var i = 0; i < binarray.length * 4; i += 3) {
            var triplet = (((binarray[i >> 2] >> 8 * (3 - i % 4)) & 0xFF) << 16) | (((binarray[i + 1 >> 2] >> 8 * (3 - (i + 1) % 4)) & 0xFF) << 8) | ((binarray[i + 2 >> 2] >> 8 * (3 - (i + 2) % 4)) & 0xFF);
            for(var j = 0; j < 4; j++) {
                if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;
                else str += tab.charAt((triplet >> 6 * (3 - j)) & 0x3F)
            }
        }
        return str
    }
    
    // 可以将exports暴露成自己的命名空间
    Util.namespace('md5', exports);

})({});