Javascript Course

The SHA (Secure Hash Algorithm) can be used to encrypt data for secure transfer between applications.
The SHA256() function returns a string with the SHA256 encrypted hash as a 64-character hexadecimal string.
It is fully compatible with UTF-8 encoding.


Code of the SHA256() function

/**
* Secure Hash Algorithm (SHA256)
* http://www.webtoolkit.info/
* Original code by Angel Marin, Paul Johnston
**/

function SHA256(s){
 var chrsz = 8;
 var hexcase = 0;

 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 S (X, n) { return ( X >>> n ) | (X << (32 - n)); }
 function R (X, n) { return ( X >>> n ); }
 function Ch(x, y, z) { return ((x & y) ^ ((~x) & z)); }
 function Maj(x, y, z) { return ((x & y) ^ (x & z) ^ (y & z)); }
 function Sigma0256(x) { return (S(x, 2) ^ S(x, 13) ^ S(x, 22)); }
 function Sigma1256(x) { return (S(x, 6) ^ S(x, 11) ^ S(x, 25)); }
 function Gamma0256(x) { return (S(x, 7) ^ S(x, 18) ^ R(x, 3)); }
 function Gamma1256(x) { return (S(x, 17) ^ S(x, 19) ^ R(x, 10)); }

 function core_sha256 (m, l) {
 var K = new Array(0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5, 0x3956C25B, 0x59F111F1, 0x923F82A4, 0xAB1C5ED5, 0xD807AA98, 0x12835B01, 0x243185BE, 0x550C7DC3, 0x72BE5D74, 0x80DEB1FE, 0x9BDC06A7, 0xC19BF174, 0xE49B69C1, 0xEFBE4786, 0xFC19DC6, 0x240CA1CC, 0x2DE92C6F, 0x4A7484AA, 0x5CB0A9DC, 0x76F988DA, 0x983E5152, 0xA831C66D, 0xB00327C8, 0xBF597FC7, 0xC6E00BF3, 0xD5A79147, 0x6CA6351, 0x14292967, 0x27B70A85, 0x2E1B2138, 0x4D2C6DFC, 0x53380D13, 0x650A7354, 0x766A0ABB, 0x81C2C92E, 0x92722C85, 0xA2BFE8A1, 0xA81A664B, 0xC24B8B70, 0xC76C51A3, 0xD192E819, 0xD6990624, 0xF40E3585, 0x106AA070, 0x19A4C116, 0x1E376C08, 0x2748774C, 0x34B0BCB5, 0x391C0CB3, 0x4ED8AA4A, 0x5B9CCA4F, 0x682E6FF3, 0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208, 0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2);
 var HASH = new Array(0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19);
 var W = new Array(64);
 var a, b, c, d, e, f, g, h, i, j;
 var T1, T2;

 m[l >> 5] |= 0x80 << (24 - l % 32);
 m[((l + 64 >> 9) << 4) + 15] = l;

 for ( var i = 0; i<m.length; i+=16 ) {
 a = HASH[0];
 b = HASH[1];
 c = HASH[2];
 d = HASH[3];
 e = HASH[4];
 f = HASH[5];
 g = HASH[6];
 h = HASH[7];

 for ( var j = 0; j<64; j++) {
 if (j < 16) W[j] = m[j + i];
 else W[j] = safe_add(safe_add(safe_add(Gamma1256(W[j - 2]), W[j - 7]), Gamma0256(W[j - 15])), W[j - 16]);

 T1 = safe_add(safe_add(safe_add(safe_add(h, Sigma1256(e)), Ch(e, f, g)), K[j]), W[j]);
 T2 = safe_add(Sigma0256(a), Maj(a, b, c));

 h = g;
 g = f;
 f = e;
 e = safe_add(d, T1);
 d = c;
 c = b;
 b = a;
 a = safe_add(T1, T2);
 }

 HASH[0] = safe_add(a, HASH[0]);
 HASH[1] = safe_add(b, HASH[1]);
 HASH[2] = safe_add(c, HASH[2]);
 HASH[3] = safe_add(d, HASH[3]);
 HASH[4] = safe_add(e, HASH[4]);
 HASH[5] = safe_add(f, HASH[5]);
 HASH[6] = safe_add(g, HASH[6]);
 HASH[7] = safe_add(h, HASH[7]);
 }
 return HASH;
 }

 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) << (24 - i % 32);
 }
 return bin;
 }

 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;
 }

 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;
 }

 s = Utf8Encode(s);
 return binb2hex(core_sha256(str2binb(s), s.length * chrsz));
}
- Usage:
1. Copy the SHA256() function into your JavaScript script.
2. To get the SHA256 hash of a string, calls the SHA256() function:   SHA256('string'); .

- Example. The string entered into an input text field will be encrypted with SHA256, and added into another input form field.
<h4>Example JavaScript SHA256</h4>

<form action='#' method='post'>
 Enter a text:<br/>
 <input type='text' name='strex' id='strex' size='25' /> <input type='button' id='cryptstr' value='Encrypt' /><br/>
 SHA256 hash string:<br/>
<input type='text' name='strcrypt' id='strcrypt' size='58' />
</form>
<script>
//code of SHA256 function
function SHA256(s){var chrsz=8;var hexcase=0;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 S(X,n){return(X>>>n)|(X<<(32-n));}
function R(X,n){return(X>>>n);}
function Ch(x,y,z){return((x&y)^((~x)&z));}
function Maj(x,y,z){return((x&y)^(x&z)^(y&z));}
function Sigma0256(x){return(S(x,2)^S(x,13)^S(x,22));}
function Sigma1256(x){return(S(x,6)^S(x,11)^S(x,25));}
function Gamma0256(x){return(S(x,7)^S(x,18)^R(x,3));}
function Gamma1256(x){return(S(x,17)^S(x,19)^R(x,10));}
function core_sha256(m,l){var K=new Array(0x428A2F98,0x71374491,0xB5C0FBCF,0xE9B5DBA5,0x3956C25B,0x59F111F1,0x923F82A4,0xAB1C5ED5,0xD807AA98,0x12835B01,0x243185BE,0x550C7DC3,0x72BE5D74,0x80DEB1FE,0x9BDC06A7,0xC19BF174,0xE49B69C1,0xEFBE4786,0xFC19DC6,0x240CA1CC,0x2DE92C6F,0x4A7484AA,0x5CB0A9DC,0x76F988DA,0x983E5152,0xA831C66D,0xB00327C8,0xBF597FC7,0xC6E00BF3,0xD5A79147,0x6CA6351,0x14292967,0x27B70A85,0x2E1B2138,0x4D2C6DFC,0x53380D13,0x650A7354,0x766A0ABB,0x81C2C92E,0x92722C85,0xA2BFE8A1,0xA81A664B,0xC24B8B70,0xC76C51A3,0xD192E819,0xD6990624,0xF40E3585,0x106AA070,0x19A4C116,0x1E376C08,0x2748774C,0x34B0BCB5,0x391C0CB3,0x4ED8AA4A,0x5B9CCA4F,0x682E6FF3,0x748F82EE,0x78A5636F,0x84C87814,0x8CC70208,0x90BEFFFA,0xA4506CEB,0xBEF9A3F7,0xC67178F2);var HASH=new Array(0x6A09E667,0xBB67AE85,0x3C6EF372,0xA54FF53A,0x510E527F,0x9B05688C,0x1F83D9AB,0x5BE0CD19);var W=new Array(64);var a,b,c,d,e,f,g,h,i,j;var T1,T2;m[l>>5]|=0x80<<(24-l % 32);m[((l+64>>9)<<4)+15]=l;for(var i=0;i<m.length;i+=16){a=HASH[0];b=HASH[1];c=HASH[2];d=HASH[3];e=HASH[4];f=HASH[5];g=HASH[6];h=HASH[7];for(var j=0;j<64;j++){if(j<16)W[j]=m[j+i];else W[j]=safe_add(safe_add(safe_add(Gamma1256(W[j-2]),W[j-7]),Gamma0256(W[j-15])),W[j-16]);T1=safe_add(safe_add(safe_add(safe_add(h,Sigma1256(e)),Ch(e,f,g)),K[j]),W[j]);T2=safe_add(Sigma0256(a),Maj(a,b,c));h=g;g=f;f=e;e=safe_add(d,T1);d=c;c=b;b=a;a=safe_add(T1,T2);}
HASH[0]=safe_add(a,HASH[0]);HASH[1]=safe_add(b,HASH[1]);HASH[2]=safe_add(c,HASH[2]);HASH[3]=safe_add(d,HASH[3]);HASH[4]=safe_add(e,HASH[4]);HASH[5]=safe_add(f,HASH[5]);HASH[6]=safe_add(g,HASH[6]);HASH[7]=safe_add(h,HASH[7]);}
return HASH;}
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)<<(24-i % 32);}
return bin;}
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;}
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;}
s=Utf8Encode(s);return binb2hex(core_sha256(str2binb(s),s.length*chrsz));}

// register onclick events for Encrypt button
document.getElementById('cryptstr').onclick = function(){
 // gets data from input text
 var txt_string = document.getElementById('strex').value;

 // encrypts data and adds it in #strcrypt element
 document.getElementById('strcrypt').value = SHA256(txt_string);
 return false;
}
</script>
Demo:
Enter a text:

SHA256 hash string:

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