The Tor Browser: mobile/android/base/sync/crypto/CryptoInfo.java@6474c204b198 (annotated)

mobile/android/base/sync/crypto/CryptoInfo.java@6474c204b198 (annotated)

mobile/android/base/sync/crypto/CryptoInfo.java

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 package org.mozilla.gecko.sync.crypto;
 import java.security.GeneralSecurityException;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
 import java.util.Arrays;
 import javax.crypto.BadPaddingException;
 import javax.crypto.Cipher;
 import javax.crypto.IllegalBlockSizeException;
 import javax.crypto.Mac;
 import javax.crypto.NoSuchPaddingException;
 import javax.crypto.spec.IvParameterSpec;
 import javax.crypto.spec.SecretKeySpec;
 import org.mozilla.apache.commons.codec.binary.Base64;
 /*
  * All info in these objects should be decoded (i.e. not BaseXX encoded).
  */
 public class CryptoInfo {
   private static final String TRANSFORMATION     = "AES/CBC/PKCS5Padding";
   private static final String KEY_ALGORITHM_SPEC = "AES";
   private byte[] message;
   private byte[] iv;
   private byte[] hmac;
   private KeyBundle keys;
   /**
    * Return a CryptoInfo with given plaintext encrypted using given keys.
    */
   public static CryptoInfo encrypt(byte[] plaintextBytes, KeyBundle keys) throws CryptoException {
     CryptoInfo info = new CryptoInfo(plaintextBytes, keys);
     info.encrypt();
     return info;
   }
   /**
    * Return a CryptoInfo with given plaintext encrypted using given keys and initial vector.
    */
   public static CryptoInfo encrypt(byte[] plaintextBytes, byte[] iv, KeyBundle keys) throws CryptoException {
     CryptoInfo info = new CryptoInfo(plaintextBytes, iv, null, keys);
     info.encrypt();
     return info;
   }
   /**
    * Return a CryptoInfo with given ciphertext decrypted using given keys and initial vector, verifying that given HMAC validates.
    */
   public static CryptoInfo decrypt(byte[] ciphertext, byte[] iv, byte[] hmac, KeyBundle keys) throws CryptoException {
     CryptoInfo info = new CryptoInfo(ciphertext, iv, hmac, keys);
     info.decrypt();
     return info;
   }
   /*
    * Constructor typically used when encrypting.
    */
   public CryptoInfo(byte[] message, KeyBundle keys) {
     this.setMessage(message);
     this.setKeys(keys);
   }
   /*
    * Constructor typically used when decrypting.
    */
   public CryptoInfo(byte[] message, byte[] iv, byte[] hmac, KeyBundle keys) {
     this.setMessage(message);
     this.setIV(iv);
     this.setHMAC(hmac);
     this.setKeys(keys);
   }
   public byte[] getMessage() {
     return message;
   }
   public void setMessage(byte[] message) {
     this.message = message;
   }
   public byte[] getIV() {
     return iv;
   }
   public void setIV(byte[] iv) {
     this.iv = iv;
   }
   public byte[] getHMAC() {
     return hmac;
   }
   public void setHMAC(byte[] hmac) {
     this.hmac = hmac;
   }
   public KeyBundle getKeys() {
     return keys;
   }
   public void setKeys(KeyBundle keys) {
     this.keys = keys;
   }
   /*
    * Generate HMAC for given cipher text.
    */
   public static byte[] generatedHMACFor(byte[] message, KeyBundle keys) throws NoSuchAlgorithmException, InvalidKeyException {
     Mac hmacHasher = HKDF.makeHMACHasher(keys.getHMACKey());
     return hmacHasher.doFinal(Base64.encodeBase64(message));
   }
   /*
    * Return true if generated HMAC is the same as the specified HMAC.
    */
   public boolean generatedHMACIsHMAC() throws NoSuchAlgorithmException, InvalidKeyException {
     byte[] generatedHMAC = generatedHMACFor(getMessage(), getKeys());
     byte[] expectedHMAC  = getHMAC();
     return Arrays.equals(generatedHMAC, expectedHMAC);
   }
   /**
    * Performs functionality common to both encryption and decryption.
    *
    * @param cipher
    * @param inputMessage non-BaseXX-encoded message
    * @return encrypted/decrypted message
    * @throws CryptoException
    */
   private static byte[] commonCrypto(Cipher cipher, byte[] inputMessage)
                         throws CryptoException {
     byte[] outputMessage = null;
     try {
       outputMessage = cipher.doFinal(inputMessage);
     } catch (IllegalBlockSizeException e) {
       throw new CryptoException(e);
     } catch (BadPaddingException e) {
       throw new CryptoException(e);
     }
     return outputMessage;
   }
   /**
    * Encrypt a CryptoInfo in-place.
    *
    * @throws CryptoException
    */
   public void encrypt() throws CryptoException {
     Cipher cipher = CryptoInfo.getCipher(TRANSFORMATION);
     try {
       byte[] encryptionKey = getKeys().getEncryptionKey();
       SecretKeySpec spec = new SecretKeySpec(encryptionKey, KEY_ALGORITHM_SPEC);
       // If no IV is provided, we allow the cipher to provide one.
       if (getIV() == null || getIV().length == 0) {
         cipher.init(Cipher.ENCRYPT_MODE, spec);
       } else {
         cipher.init(Cipher.ENCRYPT_MODE, spec, new IvParameterSpec(getIV()));
       }
     } catch (GeneralSecurityException ex) {
       throw new CryptoException(ex);
     }
     // Encrypt.
     byte[] encryptedBytes = commonCrypto(cipher, getMessage());
     byte[] iv = cipher.getIV();
     byte[] hmac;
     // Generate HMAC.
     try {
       hmac = generatedHMACFor(encryptedBytes, keys);
     } catch (NoSuchAlgorithmException e) {
       throw new CryptoException(e);
     } catch (InvalidKeyException e) {
       throw new CryptoException(e);
     }
     // Update in place.  keys is already set.
     this.setHMAC(hmac);
     this.setIV(iv);
     this.setMessage(encryptedBytes);
   }
   /**
    * Decrypt a CryptoInfo in-place.
    *
    * @throws CryptoException
    */
   public void decrypt() throws CryptoException {
     // Check HMAC.
     try {
       if (!generatedHMACIsHMAC()) {
         throw new HMACVerificationException();
       }
     } catch (NoSuchAlgorithmException e) {
       throw new CryptoException(e);
     } catch (InvalidKeyException e) {
       throw new CryptoException(e);
     }
     Cipher cipher = CryptoInfo.getCipher(TRANSFORMATION);
     try {
       byte[] encryptionKey = getKeys().getEncryptionKey();
       SecretKeySpec spec = new SecretKeySpec(encryptionKey, KEY_ALGORITHM_SPEC);
       cipher.init(Cipher.DECRYPT_MODE, spec, new IvParameterSpec(getIV()));
     } catch (GeneralSecurityException ex) {
       throw new CryptoException(ex);
     }
     byte[] decryptedBytes = commonCrypto(cipher, getMessage());
     byte[] iv = cipher.getIV();
     // Update in place.  keys is already set.
     this.setHMAC(null);
     this.setIV(iv);
     this.setMessage(decryptedBytes);
   }
   /**
    * Helper to get a Cipher object.
    *
    * @param transformation The type of Cipher to get.
    */
   private static Cipher getCipher(String transformation) throws CryptoException {
     try {
       return Cipher.getInstance(transformation);
     } catch (NoSuchAlgorithmException e) {
       throw new CryptoException(e);
     } catch (NoSuchPaddingException e) {
       throw new CryptoException(e);
     }
   }
 }

The Tor Browser / annotate

mobile/android/base/sync/crypto/CryptoInfo.java@6474c204b198 (annotated)

mobile/android/base/sync/crypto/CryptoInfo.java