javascript DES加密

研究联通wifi登陆中，发现了一个名为"encryption.js"的文件。这个文件一看即知是加密过的，首先自己尝试去手工解密，看到太烦琐了，忽然想到网上有js解密工具，遂决定用来试试看能不能解密。找了好几个js解密工具，最好的还是这个：http://www.jb51.net/tools/eval/。解密之后是用javascript实现的DES加密算法。代码如下：

var DES = {
    IP_Table: [58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7],
    IPR_Table: [40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25],
    PC1_Table: [57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4],
    PC2_Table: [14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2, 41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32],
    LOOP_Table: [1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1],
    E_Table: [32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1],
    P_Table: [16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25],
    S_Box: [[[14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7], [0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8], [4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0], [15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13]], [[15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10], [3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5], [0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15], [13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9]], [[10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8], [13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1], [13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7], [1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12]], [[7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15], [13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9], [10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4], [3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14]], [[2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9], [14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6], [4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14], [11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3]], [[12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11], [10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8], [9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6], [4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13]], [[4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1], [13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6], [1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2], [6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12]], [[13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7], [1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2], [7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8], [2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11]]],
    Oct2Bin: ["0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"],
    subKeys: new Array(16),
    key: "",
    text: ""
};
DES.init = function(key, text) {
    if (key != this.key) {
        this.key = key;
        this.GenSubKey()
    };
    this.text = text + "        ".substring(0, parseInt("07654321".charAt(text.length % 8), 10))
};
DES.GenSubKey = function() {
    var arr = this.Permute(this.Byte2Bit(this.key), this.PC1_Table);
    var AL = arr.slice(0, 28);
    var AR = arr.slice(28, 56);
    for (var i = 0; i < 16; i++) {
        for (var j = 0,
        k = this.LOOP_Table[i]; j < k; j++) {
            AL.push(AL.shift());
            AR.push(AR.shift())
        };
        this.subKeys[i] = this.Permute(AL.concat(AR), this.PC2_Table)
    }
};
DES.Bit2Byte = function(ar, fCh) {
    var str = "";
    if (fCh == "byte") {
        var tmpAr = ar.join("").match(/.{8}/g);
        for (var i = 0,
        j = tmpAr.length; i < j; i++) str += String.fromCharCode(parseInt(tmpAr[i], 2))
    } else if (fCh == "hex") {
        var tmpAr = ar.join("").match(/.{4}/g);
        for (var i = 0,
        j = tmpAr.length; i < j; i++) str += "0123456789abcdef".charAt(parseInt(tmpAr[i], 2))
    } else return "Error:Second param is wrong.";
    return str
};
DES.Byte2Bit = function(str) {
    for (var i = 0,
    j = 8 * str.length,
    ar = [], ch = ""; i < j; i++) {
        var k = 7 - i % 8;
        if (k == 7) ch = str.charCodeAt(parseInt(i / 8, 10));
        ar.push((ch >> k) & 1)
    };
    return ar
};
DES.Hex2Bin = function(str) {
    for (var i = 0,
    j = str.length,
    s = ""; i < j; i++) s += this.Oct2Bin[parseInt(str.charAt(i), 16)];
    return s.split("")
};
DES.Xor = function(A, B) {
    for (var i = 0,
    j = B.length,
    rtn = new Array(j); i < j; i++) rtn[i] = A[i] ^ B[i];
    return rtn
};
DES.Permute = function(ar, tb) {
    for (var i = 0,
    j = tb.length,
    rtn = new Array(j); i < j; i++) rtn[i] = ar[tb[i] - 1];
    return rtn
};
DES.F_func = function(Ri, Ki) {
    return this.Permute(this.S_func(this.Xor(this.Permute(Ri, this.E_Table), Ki)), this.P_Table)
};
DES.S_func = function(ar) {
    for (var i = 0,
    arRtn = []; i < 8; i++) {
        var x = i * 6;
        var j = parseInt("" + ar[x] + ar[x + 5], 2);
        var k = parseInt(ar.slice(x + 1, x + 5).join(""), 2);
        arRtn = arRtn.concat(this.Oct2Bin[this.S_Box[i][j][k]].split(""))
    };
    return arRtn
};
DES.Encrypt = function() {
    var plainTextAr = this.Byte2Bit(this.text).join("").match(/.{64}/g);
    for (var i = 0,
    j = plainTextAr.length; i < j; i++) {
        var arr = this.Permute(plainTextAr[i].split(""), this.IP_Table);
        var AL = arr.slice(0, 32);
        var AR = arr.slice(32, 64);
        for (var k = 0; k < 16; k++) {
            var tmp = AR.slice(0, 32);
            AR = this.Xor(this.F_func(AR, this.subKeys[k]), AL);
            AL = tmp
        };
        plainTextAr[i] = this.Bit2Byte(this.Permute(AR.concat(AL), this.IPR_Table), ("hex"))
    };
    return plainTextAr.join("")
};
function jiami(str) {
    if (document.getElementById("passwordkey") == null || "" == document.getElementById("passwordkey").value) {
        return str
    } else {
        DES.init(document.getElementById("passwordkey").value, str);
        return DES.Encrypt()
    }
};
var trim = function(value) {
    var res = String(value).replace(/^[\s]+|[\s]+$/g, '');
    return res
}

　　这段代码也可能是copy别人的代码，先记下来，说不定以后会用得上。最后两个函数与DES无关，是网页的应用逻辑代码。