src/flash/com/adobe/crypto/SHA1.as
/*
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*/
package com.adobe.crypto
{
import com.adobe.utils.IntUtil;
import flash.utils.ByteArray;
import mx.utils.Base64Encoder;
/**
* US Secure Hash Algorithm 1 (SHA1)
*
* Implementation based on algorithm description at
* http://www.faqs.org/rfcs/rfc3174.html
*/
public class SHA1
{
/**
* Performs the SHA1 hash algorithm on a string.
*
* @param s The string to hash
* @return A string containing the hash value of s
* @langversion ActionScript 3.0
* @playerversion 9.0
* @tiptext
*/
public static function hash( s:String ):String
{
var blocks:Array = createBlocksFromString( s );
var byteArray:ByteArray = hashBlocks( blocks );
return IntUtil.toHex( byteArray.readInt(), true )
+ IntUtil.toHex( byteArray.readInt(), true )
+ IntUtil.toHex( byteArray.readInt(), true )
+ IntUtil.toHex( byteArray.readInt(), true )
+ IntUtil.toHex( byteArray.readInt(), true );
}
/**
* Performs the SHA1 hash algorithm on a ByteArray.
*
* @param data The ByteArray data to hash
* @return A string containing the hash value of data
* @langversion ActionScript 3.0
* @playerversion 9.0
*/
public static function hashBytes( data:ByteArray ):String
{
var blocks:Array = SHA1.createBlocksFromByteArray( data );
var byteArray:ByteArray = hashBlocks(blocks);
return IntUtil.toHex( byteArray.readInt(), true )
+ IntUtil.toHex( byteArray.readInt(), true )
+ IntUtil.toHex( byteArray.readInt(), true )
+ IntUtil.toHex( byteArray.readInt(), true )
+ IntUtil.toHex( byteArray.readInt(), true );
}
/**
* Performs the SHA1 hash algorithm on a string, then does
* Base64 encoding on the result.
*
* @param s The string to hash
* @return The base64 encoded hash value of s
* @langversion ActionScript 3.0
* @playerversion 9.0
* @tiptext
*/
public static function hashToBase64( s:String ):String
{
var blocks:Array = SHA1.createBlocksFromString( s );
var byteArray:ByteArray = hashBlocks(blocks);
// ByteArray.toString() returns the contents as a UTF-8 string,
// which we can't use because certain byte sequences might trigger
// a UTF-8 conversion. Instead, we convert the bytes to characters
// one by one.
var charsInByteArray:String = "";
byteArray.position = 0;
for (var j:int = 0; j < byteArray.length; j++)
{
var byte:uint = byteArray.readUnsignedByte();
charsInByteArray += String.fromCharCode(byte);
}
var encoder:Base64Encoder = new Base64Encoder();
encoder.encode(charsInByteArray);
return encoder.flush();
}
private static function hashBlocks( blocks:Array ):ByteArray
{
// initialize the h's
var h0:int = 0x67452301;
var h1:int = 0xefcdab89;
var h2:int = 0x98badcfe;
var h3:int = 0x10325476;
var h4:int = 0xc3d2e1f0;
var len:int = blocks.length;
var w:Array = new Array( 80 );
// loop over all of the blocks
for ( var i:int = 0; i < len; i += 16 ) {
// 6.1.c
var a:int = h0;
var b:int = h1;
var c:int = h2;
var d:int = h3;
var e:int = h4;
// 80 steps to process each block
// TODO: unroll for faster execution, or 4 loops of
// 20 each to avoid the k and f function calls
for ( var t:int = 0; t < 80; t++ ) {
if ( t < 16 ) {
// 6.1.a
w[ t ] = blocks[ i + t ];
} else {
// 6.1.b
w[ t ] = IntUtil.rol( w[ t - 3 ] ^ w[ t - 8 ] ^ w[ t - 14 ] ^ w[ t - 16 ], 1 );
}
// 6.1.d
var temp:int = IntUtil.rol( a, 5 ) + f( t, b, c, d ) + e + int( w[ t ] ) + k( t );
e = d;
d = c;
c = IntUtil.rol( b, 30 );
b = a;
a = temp;
}
// 6.1.e
h0 += a;
h1 += b;
h2 += c;
h3 += d;
h4 += e;
}
var byteArray:ByteArray = new ByteArray();
byteArray.writeInt(h0);
byteArray.writeInt(h1);
byteArray.writeInt(h2);
byteArray.writeInt(h3);
byteArray.writeInt(h4);
byteArray.position = 0;
return byteArray;
}
/**
* Performs the logical function based on t
*/
private static function f( t:int, b:int, c:int, d:int ):int {
if ( t < 20 ) {
return ( b & c ) | ( ~b & d );
} else if ( t < 40 ) {
return b ^ c ^ d;
} else if ( t < 60 ) {
return ( b & c ) | ( b & d ) | ( c & d );
}
return b ^ c ^ d;
}
/**
* Determines the constant value based on t
*/
private static function k( t:int ):int {
if ( t < 20 ) {
return 0x5a827999;
} else if ( t < 40 ) {
return 0x6ed9eba1;
} else if ( t < 60 ) {
return 0x8f1bbcdc;
}
return 0xca62c1d6;
}
/**
* Converts a ByteArray to a sequence of 16-word blocks
* that we'll do the processing on. Appends padding
* and length in the process.
*
* @param data The data to split into blocks
* @return An array containing the blocks into which data was split
*/
private static function createBlocksFromByteArray( data:ByteArray ):Array
{
var oldPosition:int = data.position;
data.position = 0;
var blocks:Array = new Array();
var len:int = data.length * 8;
var mask:int = 0xFF; // ignore hi byte of characters > 0xFF
for( var i:int = 0; i < len; i += 8 )
{
blocks[ i >> 5 ] |= ( data.readByte() & mask ) << ( 24 - i % 32 );
}
// append padding and length
blocks[ len >> 5 ] |= 0x80 << ( 24 - len % 32 );
blocks[ ( ( ( len + 64 ) >> 9 ) << 4 ) + 15 ] = len;
data.position = oldPosition;
return blocks;
}
/**
* Converts a string to a sequence of 16-word blocks
* that we'll do the processing on. Appends padding
* and length in the process.
*
* @param s The string to split into blocks
* @return An array containing the blocks that s was split into.
*/
private static function createBlocksFromString( s:String ):Array
{
var blocks:Array = new Array();
var len:int = s.length * 8;
var mask:int = 0xFF; // ignore hi byte of characters > 0xFF
for( var i:int = 0; i < len; i += 8 ) {
blocks[ i >> 5 ] |= ( s.charCodeAt( i / 8 ) & mask ) << ( 24 - i % 32 );
}
// append padding and length
blocks[ len >> 5 ] |= 0x80 << ( 24 - len % 32 );
blocks[ ( ( ( len + 64 ) >> 9 ) << 4 ) + 15 ] = len;
return blocks;
}
}
}