diff --git a/source/Ox/js/Hash.js b/source/Ox/js/Hash.js
index 20175b9e..7471604d 100644
--- a/source/Ox/js/Hash.js
+++ b/source/Ox/js/Hash.js
@@ -11,7 +11,7 @@ Ox.oshash = function(file, callback) {
     read(0);
 
     function add(A, B) {
-        var a, b, c, d; 
+        var a, b, c, d;
         d = A[3] + B[3];
         c = A[2] + B[2] + (d >> 16);
         d &= 0xffff;
@@ -23,7 +23,7 @@ Ox.oshash = function(file, callback) {
         a &= 0xffff;
         return [a, b, c, d];
     }
-    
+
     function fromData(s, offset) {
         offset = offset || 0;
         return [
@@ -96,3 +96,133 @@ Ox.oshash = function(file, callback) {
     }
 
 };
+
+/*@
+Ox.SHA1 <f> Calculates SHA1 hash of the given string
+@*/
+Ox.SHA1 = function(msg) {
+
+    function rotate_left(n,s) {
+        var t4 = ( n<<s ) | (n>>>(32-s));
+        return t4;
+    };
+
+    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;
+    };
+
+    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 = Ox.encodeUTF8(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();
+}