cz.d1x.dxcrypto.encryption.crypto

Class AESBuilder

java.lang.Object

cz.d1x.dxcrypto.encryption.crypto.SymmetricAlgorithmBuilder

cz.d1x.dxcrypto.encryption.crypto.AESBuilder

All Implemented Interfaces:

EncryptionAlgorithmBuilder

public class AESBuilder
extends SymmetricAlgorithmBuilder

Builder for AES encryption algorithm with these properties:

• Type of cipher: Symmetric
• Operation mode: Cipher Block Chaining (CBC)
• Input padding: PKCS#5
• Encryption key: PBKDF2 with HMAC-SHA1 for key derivation (can be overridden)

By default, PBKDF2 is used for key derivation. You can provide salt and iterations count for it. If you want custom encryption key derivation, you can use AESBuilder(CryptoKeyFactory) constructor to specify custom factory for the key.

Recommended usage:

 EncryptionAlgorithm aes = new AESBuilder("secret")
      .keySalt("saltForKeyDerivation") // optional
      .iterations(4096) // optional
      .build();
 

Note that this builder is mutable but built instances are immutable and thus thread safe. For more information about the implementation (e.g. about initialization vectors), see SymmetricAlgorithm.

Author:

Zdenek Obst, zdenek.obst-at-gmail.com

See Also:

SymmetricAlgorithm

Constructor Summary

Constructors

Constructor and Description
AESBuilder(byte[] keyPassword) Creates a new builder for AES encryption algorithm.
AESBuilder(CryptoKeyFactory customKeyFactory) Crates a new builder for AES encryption algorithm.
AESBuilder(String keyPassword) Creates a new builder for AES encryption algorithm.

Method Summary

Modifier and Type	Method and Description
protected String	getAlgorithm() Gets a name of algorithm supported by crypto.
protected int	getBlockSize() Gets a block size of cipher (for CBC).
protected int	getKeySize() Gets size of the key.
protected String	getShortAlgorithm() Gets a short name of algorithm supported by crypto keys.

Methods inherited from class cz.d1x.dxcrypto.encryption.crypto.SymmetricAlgorithmBuilder

build, combineAlgorithm, encoding, keyHashIterations, keySalt, keySalt

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AESBuilder

public AESBuilder(byte[] keyPassword)

Creates a new builder for AES encryption algorithm.

Parameters:

keyPassword - password for key derivation

AESBuilder

public AESBuilder(String keyPassword)

Creates a new builder for AES encryption algorithm.

Parameters:

keyPassword - password for key derivation

AESBuilder

public AESBuilder(CryptoKeyFactory customKeyFactory)

Crates a new builder for AES encryption algorithm. Use this constructor if you want override default PBKDF2 for key derivation.

Parameters:

customKeyFactory - custom factory for encryption key

Method Detail

getAlgorithm

protected String getAlgorithm()

Description copied from class: SymmetricAlgorithmBuilder

Gets a name of algorithm supported by crypto.

Specified by:

getAlgorithm in class SymmetricAlgorithmBuilder

Returns:

algorithm name

getShortAlgorithm

protected String getShortAlgorithm()

Description copied from class: SymmetricAlgorithmBuilder

Gets a short name of algorithm supported by crypto keys.

Specified by:

getShortAlgorithm in class SymmetricAlgorithmBuilder

Returns:

algorithm name

getKeySize

protected int getKeySize()

Description copied from class: SymmetricAlgorithmBuilder

Gets size of the key.

Specified by:

getKeySize in class SymmetricAlgorithmBuilder

Returns:

size of key

getBlockSize

protected int getBlockSize()

Description copied from class: SymmetricAlgorithmBuilder

Gets a block size of cipher (for CBC).

Specified by:

getBlockSize in class SymmetricAlgorithmBuilder

Returns:

cipher block size