1 /*

     2  * Copyright (c) 2010, Isode Limited, London, England.

     3  * All rights reserved.

     4  */

     5 /*

     6  * Copyright (c) 2010, Remko Tronçon.

     7  * All rights reserved.

     8  */

     9 package com.isode.stroke.stringcodecs;

    10 

    11 import com.isode.stroke.base.ByteArray;

    12 

    13 public class HMACSHA1 {

    14 

    15     private static final int B = 64;

    16 

    17     public static ByteArray getResult(ByteArray key, ByteArray data) {

    18         assert key.getSize() <= B;

    19 

    20         /* And an assert that does something */

    21         if (key.getSize() > B) {

    22             throw new IllegalStateException("Invalid key size.");

    23         }

    24 

    25         // Create the padded key

    26         ByteArray paddedKey = new ByteArray(key);

    27         for (int i = key.getSize(); i < B; ++i) {

    28             paddedKey.append((byte) 0x0);

    29         }

    30 

    31         // Create the first value

    32         ByteArray x = new ByteArray(paddedKey);

    33         byte[] xInner = x.getData();

    34         for (int i = 0; i < xInner.length; ++i) {

    35             xInner[i] ^= 0x36;

    36         }

    37         x.append(data);

    38 

    39         // Create the second value

    40         ByteArray y = new ByteArray(paddedKey);

    41         byte[] yInner = y.getData();

    42         for (int i = 0; i < yInner.length; ++i) {

    43             yInner[i] ^= 0x5c;

    44         }

    45         y.append(SHA1.getHash(x));

    46 

    47         return SHA1.getHash(y);

    48     }

    49 }