javascript sha1

    /*
     * UTF-8 encoding
     */
    function utf8_encode(argString) {
      return unescape(encodeURIComponent(argString));
    }

   /************************************************************
     * sha1
     * - based on sha1 from http://phpjs.org/functions/sha1:512 (MIT / GPL v2)
     ************************************************************/

    function sha1(str) {
      // +   original by: Webtoolkit.info (http://www.webtoolkit.info/)
      // + namespaced by: Michael White (http://getsprink.com)
      // +      input by: Brett Zamir (http://brett-zamir.me)
      // +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
      // +   jslinted by: Anthon Pang (http://edc.org)

      var
        rotate_left = function (n, s) {
          return (n << s) | (n >>> (32 - s));
        },

        cvt_hex = function (val) {
          var strout = '',
            i,
            v;

          for (i = 7; i >= 0; i--) {
            v = (val >>> (i * 4)) & 0x0f;
            strout += v.toString(16);
          }

          return strout;
        },

        blockstart,
        i,
        j,
        W = [],
        H0 = 0x67452301,
        H1 = 0xEFCDAB89,
        H2 = 0x98BADCFE,
        H3 = 0x10325476,
        H4 = 0xC3D2E1F0,
        A,
        B,
        C,
        D,
        E,
        temp,
        str_len,
        word_array = [];

      str = utf8_encode(str);
      str_len = str.length;

      for (i = 0; i < str_len - 3; i += 4) {
        j = str.charCodeAt(i) << 24 | str.charCodeAt(i + 1) << 16 |
          str.charCodeAt(i + 2) << 8 | str.charCodeAt(i + 3);
        word_array.push(j);
      }

      switch (str_len & 3) {
        case 0:
          i = 0x080000000;
          break;
        case 1:
          i = str.charCodeAt(str_len - 1) << 24 | 0x0800000;
          break;
        case 2:
          i = str.charCodeAt(str_len - 2) << 24 | str.charCodeAt(str_len - 1) << 16 | 0x08000;
          break;
        case 3:
          i = str.charCodeAt(str_len - 3) << 24 | str.charCodeAt(str_len - 2) << 16 | str.charCodeAt(str_len - 1) << 8 | 0x80;
          break;
      }

      word_array.push(i);

      while ((word_array.length & 15) !== 14) {
        word_array.push(0);
      }

      word_array.push(str_len >>> 29);
      word_array.push((str_len << 3) & 0x0ffffffff);

      for (blockstart = 0; blockstart < word_array.length; blockstart += 16) {
        for (i = 0; i < 16; i++) {
          W[i] = word_array[blockstart + i];
        }

        for (i = 16; i <= 79; i++) {
          W[i] = rotate_left(W[i - 3] ^ W[i - 8] ^ W[i - 14] ^ W[i - 16], 1);
        }

        A = H0;
        B = H1;
        C = H2;
        D = H3;
        E = H4;

        for (i = 0; i <= 19; i++) {
          temp = (rotate_left(A, 5) + ((B & C) | (~B & D)) + E + W[i] + 0x5A827999) & 0x0ffffffff;
          E = D;
          D = C;
          C = rotate_left(B, 30);
          B = A;
          A = temp;
        }

        for (i = 20; i <= 39; i++) {
          temp = (rotate_left(A, 5) + (B ^ C ^ D) + E + W[i] + 0x6ED9EBA1) & 0x0ffffffff;
          E = D;
          D = C;
          C = rotate_left(B, 30);
          B = A;
          A = temp;
        }

        for (i = 40; i <= 59; i++) {
          temp = (rotate_left(A, 5) + ((B & C) | (B & D) | (C & D)) + E + W[i] + 0x8F1BBCDC) & 0x0ffffffff;
          E = D;
          D = C;
          C = rotate_left(B, 30);
          B = A;
          A = temp;
        }

        for (i = 60; i <= 79; i++) {
          temp = (rotate_left(A, 5) + (B ^ C ^ D) + E + W[i] + 0xCA62C1D6) & 0x0ffffffff;
          E = D;
          D = C;
          C = rotate_left(B, 30);
          B = A;
          A = temp;
        }

        H0 = (H0 + A) & 0x0ffffffff;
        H1 = (H1 + B) & 0x0ffffffff;
        H2 = (H2 + C) & 0x0ffffffff;
        H3 = (H3 + D) & 0x0ffffffff;
        H4 = (H4 + E) & 0x0ffffffff;
      }

      temp = cvt_hex(H0) + cvt_hex(H1) + cvt_hex(H2) + cvt_hex(H3) + cvt_hex(H4);

      return temp.toLowerCase();
    }