SHA1 Encrypt Hash in JavaScript

The SHA (Secure Hash Algorithm) can be used to encrypt data for secure transfer between applications and server.

The SHA1() function returns a string with the SHA1 encrypted hash as a string with 40 characters.

It is fully compatible with UTF-8 encoding.

<script type="text/javascript">

/**

*  Secure Hash Algorithm (SHA1)

*  http://ramsis-code.blogspot.in/

**/

function SHA1(msg) {

  function rotate_left(n,s) {

    var t4 = ( n<<s ) | (n>>>(32-s));

    return t4;

  };

  function lsb_hex(val) {

    var str="";

    var i;

    var vh;

    var vl;

    for( i=0; i<=6; i+=2 ) {

      vh = (val>>>(i*4+4))&0x0f;

      vl = (val>>>(i*4))&0x0f;

      str += vh.toString(16) + vl.toString(16);

    }

    return str;

  };

  function cvt_hex(val) {

    var str="";

    var i;

    var v;

    for( i=7; i>=0; i-- ) {

      v = (val>>>(i*4))&0x0f;

      str += v.toString(16);

    }

    return str;

  };

  function Utf8Encode(string) {

    string = string.replace(/\r\n/g,"\n");

    var utftext = "";

    for (var n = 0; n < string.length; n++) {

      var c = string.charCodeAt(n);

      if (c < 128) {

        utftext += String.fromCharCode(c);

      }

      else if((c > 127) && (c < 2048)) {

        utftext += String.fromCharCode((c >> 6) | 192);

        utftext += String.fromCharCode((c & 63) | 128);

      }

      else {

        utftext += String.fromCharCode((c >> 12) | 224);

        utftext += String.fromCharCode(((c >> 6) & 63) | 128);

        utftext += String.fromCharCode((c & 63) | 128);

      }

    }

    return utftext;

  };

  var blockstart;

  var i, j;

  var W = new Array(80);

  var H0 = 0x67452301;

  var H1 = 0xEFCDAB89;

  var H2 = 0x98BADCFE;

  var H3 = 0x10325476;

  var H4 = 0xC3D2E1F0;

  var A, B, C, D, E;

  var temp;

  msg = Utf8Encode(msg);

  var msg_len = msg.length;

  var word_array = new Array();

  for( i=0; i<msg_len-3; i+=4 ) {

    j = msg.charCodeAt(i)<<24 | msg.charCodeAt(i+1)<<16 |

    msg.charCodeAt(i+2)<<8 | msg.charCodeAt(i+3);

    word_array.push( j );

  }

  switch( msg_len % 4 ) {

    case 0:

      i = 0x080000000;

    break;

    case 1:

      i = msg.charCodeAt(msg_len-1)<<24 | 0x0800000;

    break;

    case 2:

      i = msg.charCodeAt(msg_len-2)<<24 | msg.charCodeAt(msg_len-1)<<16 | 0x08000;

    break;

    case 3:

      i = msg.charCodeAt(msg_len-3)<<24 | msg.charCodeAt(msg_len-2)<<16 | msg.charCodeAt(msg_len-1)<<8  | 0x80;

    break;

  }

  word_array.push( i );

  while( (word_array.length % 16) != 14 ) word_array.push( 0 );

  word_array.push( msg_len>>>29 );

  word_array.push( (msg_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;

  }

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

  return temp.toLowerCase();

}

</script

<form action="#" method="post">

<Strong>Enter any text:</strong><br/>

<input type="text" name="strex" id="strex" size="20" /> <button id="cryptstr">SHA1 Encrypt</button><br/>

<Strong>SHA1 Encrypted Hash String:</Strong><br/>

<input type="text" name="strcrypt" id="strcrypt" size="50" />

</form>

<script type="text/javascript">

// Here add the code of the SHA1 function

// register onclick events for Encrypt button

document.getElementById('cryptstr').onclick = function() {

var txt_string = document.getElementById('strex').value;    // gets data from input text

// encrypts data and adds it in #strcrypt element

document.getElementById('strcrypt').value = SHA1(txt_string);

return false;

}

</script>