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base64编码加密



 
   
 <script language=网页特效>
var base64encodechars = "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789+/";
var base64decodechars = new array(
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
    -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);

function base64encode(str) {
    var out, i, len;
    var c1, c2, c3;

    len = str.length;
    i = 0;
    out = "";
    while(i < len) {
    c1 = str.charcodeat(i++) & 0xff;
    if(i == len)
    {
        out += base64encodechars.charat(c1 >> 2);
        out += base64encodechars.charat((c1 & 0x3) << 4);
        out += "==";
        break;
    }
    c2 = str.charcodeat(i++);
    if(i == len)
    {
        out += base64encodechars.charat(c1 >> 2);
        out += base64encodechars.charat(((c1 & 0x3)<< 4) | ((c2 & 0xf0) >> 4));
        out += base64encodechars.charat((c2 & 0xf) << 2);
        out += "=";
        break;
    }
    c3 = str.charcodeat(i++);
    out += base64encodechars.charat(c1 >> 2);
    out += base64encodechars.charat(((c1 & 0x3)<< 4) | ((c2 & 0xf0) >> 4));
    out += base64encodechars.charat(((c2 & 0xf) << 2) | ((c3 & 0xc0) >>6));
    out += base64encodechars.charat(c3 & 0x3f);
    }
    return out;
}

function base64decode(str) {
    var c1, c2, c3, c4;
    var i, len, out;

    len = str.length;
    i = 0;
    out = "";
    while(i < len) {
    /* c1 */
    do {
        c1 = base64decodechars[str.charcodeat(i++) & 0xff];
    } while(i < len && c1 == -1);
    if(c1 == -1)
        break;

    /* c2 */
    do {
        c2 = base64decodechars[str.charcodeat(i++) & 0xff];
    } while(i < len && c2 == -1);
    if(c2 == -1)
        break;

    out += string.fromcharcode((c1 << 2) | ((c2 & 0x30) >> 4));

    /* c3 */
    do {
        c3 = str.charcodeat(i++) & 0xff;
        if(c3 == 61)
        return out;
        c3 = base64decodechars[c3];
    } while(i < len && c3 == -1);
    if(c3 == -1)
        break;

    out += string.fromcharcode(((c2 & 0xf) << 4) | ((c3 & 0x3c) >> 2));

    /* c4 */
    do {
        c4 = str.charcodeat(i++) & 0xff;
        if(c4 == 61)
        return out;
        c4 = base64decodechars[c4];
    } while(i < len && c4 == -1);
    if(c4 == -1)
        break;
    out += string.fromcharcode(((c3 & 0x03) << 6) | c4);
    }
    return out;
}

function utf16to8(str) {
    var out, i, len, c;

    out = "";
    len = str.length;
    for(i = 0; i < len; i++) {
    c = str.charcodeat(i);
    if ((c >= 0x0001) && (c <= 0x007f)) {
        out += str.charat(i);
    } else if (c > 0x07ff) {
        out += string.fromcharcode(0xe0 | ((c >> 12) & 0x0f));
        out += string.fromcharcode(0x80 | ((c >>  6) & 0x3f));
        out += string.fromcharcode(0x80 | ((c >>  0) & 0x3f));
    } else {
        out += string.fromcharcode(0xc0 | ((c >>  6) & 0x1f));
        out += string.fromcharcode(0x80 | ((c >>  0) & 0x3f));
    }
    }
    return out;
}

function utf8to16(str) {
    var out, i, len, c;
    var char2, char3;

    out = "";
    len = str.length;
    i = 0;
    while(i < len) {
    c = str.charcodeat(i++);
    switch(c >> 4)
    {
      case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
        // 0xxxxxxx
        out += str.charat(i-1);
        break;
      case 12: case 13:
        // 110x xxxx   10xx xxxx
        char2 = str.charcodeat(i++);
        out += string.fromcharcode(((c & 0x1f) << 6) | (char2 & 0x3f));
        break;
      case 14:
        // 1110 xxxx  10xx xxxx  10xx xxxx
        char2 = str.charcodeat(i++);
        char3 = str.charcodeat(i++);
        out += string.fromcharcode(((c & 0x0f) << 12) |
                       ((char2 & 0x3f) << 6) |
                       ((char3 & 0x3f) << 0));
        break;
    }
    }

    return out;
}


function doit() {
    var f = document.f
    f.output.value = base64encode(utf16to8(f.source.value))
    f.decode.value = utf8to16(base64decode(f.output.value))
}
</script>

base64编码加密



原码




base64 encode




base64 decode







 


 

本文来源:http://www.gdgbn.com/wangyezhizuo/27566/