cz.d1x.dxcrypto.encryption

Class SymmetricAlgorithmBuilder

java.lang.Object

cz.d1x.dxcrypto.encryption.SymmetricAlgorithmBuilder

public final class SymmetricAlgorithmBuilder
extends Object

Base builder for symmetric key algorithms based on GenericEncryptionAlgorithm.

Author:

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

See Also:

GenericEncryptionAlgorithm

Constructor Summary

Constructors

Constructor and Description
SymmetricAlgorithmBuilder(SymmetricEncryptionEngineFactory engineFactory, byte[] keyPassword, int keySize, int blockSize) Creates a new builder.

Method Summary

Modifier and Type	Method and Description
EncryptionAlgorithm	build() Builds a new instance of encryption algorithm.
SymmetricAlgorithmBuilder	bytesRepresentation(BytesRepresentation bytesRepresentation) Sets how byte arrays will be represented in strings.
SymmetricAlgorithmBuilder	encoding(String encoding) Sets encoding for strings in input and output.
SymmetricAlgorithmBuilder	engineFactory(SymmetricEncryptionEngineFactory engineFactory) Sets factory for encryption engine.
SymmetricAlgorithmBuilder	ivAndOutputCombining(CombiningSplitting ivOutputCombining) Sets algorithm combining initialization vector and cipher text in output during encryption and splitting from input during decryption.
SymmetricAlgorithmBuilder	ivFactory(ByteArrayFactory ivFactory) Sets algorithm for generation of initialization vector for every message.
SymmetricAlgorithmBuilder	keyHashIterations(int keyHashIterations) Sets number of iterations of hashing for key derivation.
SymmetricAlgorithmBuilder	keySalt(byte[] keySalt) Sets salt for key derivation.
SymmetricAlgorithmBuilder	keySalt(String keySalt) Sets salt for key derivation.

Methods inherited from class java.lang.Object

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

Constructor Detail

SymmetricAlgorithmBuilder

public SymmetricAlgorithmBuilder(SymmetricEncryptionEngineFactory engineFactory,
                                 byte[] keyPassword,
                                 int keySize,
                                 int blockSize)

Creates a new builder.

Parameters:

engineFactory - factory for encryption engine

keyPassword - key password

keySize - size of the key (in bits)

blockSize - size of the block (in bits)

Method Detail

engineFactory

public SymmetricAlgorithmBuilder engineFactory(SymmetricEncryptionEngineFactory engineFactory)
                                        throws IllegalArgumentException

Sets factory for encryption engine.

Parameters:

engineFactory - factory for encryption engine

Returns:

this instance

Throws:

IllegalArgumentException - exception if passed factory is null

keySalt

public SymmetricAlgorithmBuilder keySalt(byte[] keySalt)
                                  throws IllegalArgumentException

Sets salt for key derivation. Recommended length is at least 8 bytes.

Parameters:

keySalt - salt to be set

Returns:

this instance

Throws:

IllegalArgumentException - exception if passed key salt is null

keySalt

public SymmetricAlgorithmBuilder keySalt(String keySalt)
                                  throws IllegalArgumentException

Sets salt for key derivation. Recommended length is at least 8 bytes.

Parameters:

keySalt - salt to be set

Returns:

this instance

Throws:

IllegalArgumentException - exception if passed key salt is null

keyHashIterations

public SymmetricAlgorithmBuilder keyHashIterations(int keyHashIterations)
                                            throws IllegalArgumentException

Sets number of iterations of hashing for key derivation. Recommended count is at least 1000.

Parameters:

keyHashIterations - number of keyHashIterations

Returns:

this instance

Throws:

IllegalArgumentException - exception if passed iterations are lower than 1

ivFactory

public SymmetricAlgorithmBuilder ivFactory(ByteArrayFactory ivFactory)
                                    throws IllegalArgumentException

Sets algorithm for generation of initialization vector for every message. This is used only for algorithms that use it (typically CBC-based algorithms like AES, 3DES...). Note that it is recommended to have unique initialization vector for every message that is later combined with encrypted output via ivAndOutputCombining(CombiningSplitting) into the final output.

Parameters:

ivFactory - factory for initialization vector

Returns:

this instance

Throws:

IllegalArgumentException - exception if passed ByteArrayFactory is null

ivAndOutputCombining

public SymmetricAlgorithmBuilder ivAndOutputCombining(CombiningSplitting ivOutputCombining)
                                               throws IllegalArgumentException

Sets algorithm combining initialization vector and cipher text in output during encryption and splitting from input during decryption.

Parameters:

ivOutputCombining - combine/split algorithm for IV and cipher text

Returns:

this instance

Throws:

IllegalArgumentException - exception if passed CombiningSplitting is null

bytesRepresentation

public SymmetricAlgorithmBuilder bytesRepresentation(BytesRepresentation bytesRepresentation)
                                              throws IllegalArgumentException

Sets how byte arrays will be represented in strings. By default HexRepresentation is used.

Parameters:

bytesRepresentation - byte array representation strategy

Returns:

this instance

Throws:

IllegalArgumentException - exception if passed BytesRepresentation is null

encoding

public SymmetricAlgorithmBuilder encoding(String encoding)
                                   throws IllegalArgumentException

Sets encoding for strings in input and output.

Parameters:

encoding - encoding to be set

Returns:

this instance

Throws:

IllegalArgumentException - exception if given encoding is null or not supported

build

public EncryptionAlgorithm build()
                          throws IllegalArgumentException

Builds a new instance of encryption algorithm.

Returns:

algorithm instance

Throws:

IllegalArgumentException