HMAC算法AS3版

HMAC算法AS3版

/**
* HMAC
*
* An ActionScript 3 implementation of HMAC, Keyed-Hashing for Message
* Authentication, as defined by RFC-2104
* Copyright (c) 2007 Henri Torgemane
*
*/
package com.hurlant.crypto.hash
{
import flash.utils.ByteArray;
import com.hurlant.util.Hex;

public class HMAC
{
    private var hash:IHash;
    private var bits:uint;

    /**
     * Create a HMAC object, using a Hash function, and
     * optionally a number of bits to return.
     * The HMAC will be truncated to that size if needed.
     */
    public function HMAC(hash:IHash, bits:uint=0) {
      this.hash = hash;
      this.bits = bits;
    }

    /**
     * Compute a HMAC using a key and some data.
     * It doesn't modify either, and returns a new ByteArray with the HMAC value.
     */
    public function compute(key:ByteArray, data:ByteArray):ByteArray {
      var hashKey:ByteArray;
      if (key.length>hash.getInputSize()) {
        hashKey = hash.hash(key);
      } else {
        hashKey = new ByteArray;
        hashKey.writeBytes(key);
      }
      while (hashKey.length<hash.getInputSize()) {
        hashKey[hashKey.length]=0;
      }
      var innerKey:ByteArray = new ByteArray;
      var outerKey:ByteArray = new ByteArray;
      for (var i:uint=0;i<hashKey.length;i++) {
        innerKey[i] = hashKey[i] ^ 0x36;
        outerKey[i] = hashKey[i] ^ 0x5c;
      }
      // inner + data
      innerKey.position = hashKey.length;
      innerKey.writeBytes(data);
      var innerHash:ByteArray = hash.hash(innerKey);
      // outer + innerHash
      outerKey.position = hashKey.length;
      outerKey.writeBytes(innerHash);
      var outerHash:ByteArray = hash.hash(outerKey);
      if (bits>0 && bits<8*outerHash.length) {
        outerHash.length = bits/8;
      }
      return outerHash;
    }
    public function dispose():void {
      hash = null;
      bits = 0;
    }
    public function toString():String {
      return "hmac-"+(bits>0?bits+"-":"")+hash.toString();
    }

}
}
算法的使用：
这个HMAC算法加密和解密均使用ByteArray，使用时需要使用hurlant 的Hex类中对应的方法转换数据类型。
引用
If you want a HMAC of SHA-224 with 128 significant bits, you can use
var hmac:HMAC = Crypto.getHMAC(”hmac-128-sha224″);
You can then use it as:
var value:ByteArray = hmac.compute(key, data);
<?xml version="1.0" encoding="utf-8"?>

<mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml" label="HMAC" width="100%" height="100%">
<mx:Label text="Hash Function:" left="10" top="10"/>
<mx:ComboBox id="hashType" labelField="@label" left="106" top="8">
<mx:dataProvider>
    <mx:XMLList>
      <item label="SHA-256" value="sha256"/>
      <item label="SHA-224" value="sha224"/>
      <item label="SHA-1" value="sha1"/>
      <item label="MD5" value="md5"/>
      <item label="MD2" value="md2"/>
    </mx:XMLList>
</mx:dataProvider>
</mx:ComboBox>
<mx:Label x="10" y="36" text="Key Format:"/>
<mx:ComboBox id="keyFormat" labelField="@label" left="91" top="34">
<mx:dataProvider>
    <mx:XMLList>
      <item label="Text" value="text"/>
      <item label="Hex" value="hex"/>
      <item label="Base64" value="b64"/>
    </mx:XMLList>
</mx:dataProvider>
</mx:ComboBox>
<mx:TextArea id="key" left="10" right="10" top="62" height="50"/>
<mx:Label text="Input Format:" left="10" top="120"/>
<mx:ComboBox id="inputFormat" labelField="@label" left="91" top="118">
<mx:dataProvider>
    <mx:XMLList>
      <item label="Text" value="text"/>
      <item label="Hex" value="hex"/>
      <item label="Base64" value="b64"/>
    </mx:XMLList>
</mx:dataProvider>
</mx:ComboBox>
<mx:TextArea id="input" left="10" right="10" top="146" bottom="148"/>
<mx:Label text="Output Format:" left="10" bottom="120"/>
<mx:ComboBox id="outputFormat" labelField="@label" bottom="118" left="109" change="displayOutput()">
<mx:dataProvider>
    <mx:XMLList>
      <item label="Text" value="text"/>
      <item label="Hex" value="hex"/>
      <item label="Base64" value="b64"/>
    </mx:XMLList>
</mx:dataProvider>
</mx:ComboBox>
<mx:TextArea id="output" height="100" right="10" left="10" bottom="10" editable="false"/>
<mx:Button label="Compute HMAC" right="10" click="computeHMAC()" bottom="118"/>

<mx:Script>
    <![CDATA[
import com.hurlant.crypto.hash.HMAC;
      import com.hurlant.util.Base64;
      import com.hurlant.util.Hex;
      import com.hurlant.crypto.Crypto;
      import com.hurlant.crypto.hash.IHash;

      private var currentResult:ByteArray;

      private function computeHMAC():void {
        // 1: get a IHash.
        var hmac:HMAC = Crypto.getHMAC(hashType.selectedItem.@value);
        // 2: get a key
        var k:String = key.text;
        var kdata:ByteArray;
        var kformat:String = String(keyFormat.selectedItem.@value);
        switch (kformat) {
          case "hex": kdata = Hex.toArray(k); break;
          case "b64": kdata = Base64.decodeToByteArray(k); break;
          default:
            kdata = Hex.toArray(Hex.fromString(k));
        }
        // 3: get an input
        var txt:String = input.text;
        var data:ByteArray;
        var format:String = String(inputFormat.selectedItem.@value);
        switch (format) {
          case "hex": data = Hex.toArray(txt); break;
          case "b64": data = Base64.decodeToByteArray(txt); break;
          default:
            data = Hex.toArray(Hex.fromString(txt));
        }
        currentResult = hmac.compute(kdata, data);
        displayOutput();
      }
      private function displayOutput():void {
        if (currentResult==null) return;
        var txt:String;
        var format:String = String(outputFormat.selectedItem.@value);
        switch (format) {
          case "hex": txt = Hex.fromArray(currentResult); break;
          case "b64": txt = Base64.encodeByteArray(currentResult); break;
          default:
            txt = Hex.toString(Hex.fromArray(currentResult)); break;
        }
        trace("txt="+txt);
        output.text = txt;
      }
]]>
</mx:Script>
</mx:Canvas>