Package org.cryptacular.bean

Class AbstractCipherBean

java.lang.Object

org.cryptacular.bean.AbstractCipherBean

All Implemented Interfaces:

CipherBean

Direct Known Subclasses:

AbstractBlockCipherBean

public abstract class AbstractCipherBean
extends Object
implements CipherBean

Base class for all cipher beans. The base class assumes all ciphertext output will contain a prepended CiphertextHeader containing metadata that facilitates decryption.

Author:

Middleware Services

Constructor Summary

Constructors

Constructor	Description
AbstractCipherBean(KeyStore keyStore, String keyAlias, String keyPassword, Nonce nonce)	Creates a new abstract cipher bean.

Method Summary

Modifier and Type	Method	Description
byte[]	decrypt(byte[] input)	Decrypts the input data using a block cipher.
void	decrypt(InputStream input, OutputStream output)	Decrypts the data from the input stream onto the output stream using a symmetric cipher.
byte[]	encrypt(byte[] input)	Encrypts the input data using a symmetric cipher.
void	encrypt(InputStream input, OutputStream output)	Encrypts the data from the input stream onto the output stream using a symmetric cipher.
String	getKeyAlias()
KeyStore	getKeyStore()
Nonce	getNonce()
protected SecretKey	lookupKey(String alias)	Looks up secret key entry in the keyStore.
protected abstract byte[]	process(CiphertextHeader header, boolean mode, byte[] input)	Processes the given data under the action of the cipher.
protected abstract void	process(CiphertextHeader header, boolean mode, InputStream input, OutputStream output)	Processes the given data under the action of the cipher.

Methods inherited from class java.lang.Object

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

Constructor Details

AbstractCipherBean

public AbstractCipherBean(KeyStore keyStore,
 String keyAlias,
 String keyPassword,
 Nonce nonce)

Creates a new abstract cipher bean. The keystore must contain a SecretKey entry whose alias is given by the supplied alias, which will be used at the encryption key. It may contain additional symmetric keys to support, for example, key rollover where some existing ciphertexts have headers specifying a different key. In general all keys used for outstanding ciphertexts should be contained in the keystore.

Parameters:

keyStore - Key store containing encryption key.

keyAlias - Name of encryption key entry in key store.

keyPassword - Password used to decrypt key entry in keystore.

nonce - Nonce/IV generator.

Method Details

getKeyStore

public KeyStore getKeyStore()

Returns:

Keystore that contains the SecretKey.

getKeyAlias

public String getKeyAlias()

Returns:

Alias that specifies the KeyStore entry containing the SecretKey.

getNonce

public Nonce getNonce()

Returns:

Nonce/IV generation strategy.

encrypt

public byte[] encrypt(byte[] input)
               throws CryptoException

Description copied from interface: CipherBean

Encrypts the input data using a symmetric cipher.

Specified by:

encrypt in interface CipherBean

Parameters:

input - Plaintext data to encrypt.

Returns:

Ciphertext output.

Throws:

CryptoException - on underlying cipher data handling errors.

encrypt

public void encrypt(InputStream input,
 OutputStream output)
             throws CryptoException,
StreamException

Description copied from interface: CipherBean

Encrypts the data from the input stream onto the output stream using a symmetric cipher.

The caller is responsible for providing and managing the streams (e.g. closing them when finished).

Specified by:

encrypt in interface CipherBean

Parameters:

input - Input stream containing plaintext data to encrypt.

output - Output stream containing ciphertext produced by cipher in encryption mode.

Throws:

CryptoException - on underlying cipher data handling errors.

StreamException - on stream IO errors.

decrypt

public byte[] decrypt(byte[] input)
               throws CryptoException,
EncodingException

Description copied from interface: CipherBean

Decrypts the input data using a block cipher.

Specified by:

decrypt in interface CipherBean

Parameters:

input - Ciphertext data to encrypt.

Returns:

Plaintext output.

Throws:

CryptoException - on underlying cipher data handling errors.

EncodingException

decrypt

public void decrypt(InputStream input,
 OutputStream output)
             throws CryptoException,
EncodingException,
StreamException

Description copied from interface: CipherBean

Decrypts the data from the input stream onto the output stream using a symmetric cipher.

The caller is responsible for providing and managing the streams (e.g. closing them when finished).

Specified by:

decrypt in interface CipherBean

Parameters:

input - Input stream containing ciphertext data to decrypt.

output - Output stream containing plaintext produced by cipher in decryption mode.

Throws:

CryptoException - on underlying cipher data handling errors.

StreamException - on stream IO errors.

EncodingException

lookupKey

protected SecretKey lookupKey(String alias)

Looks up secret key entry in the keyStore.

Parameters:

alias - Name of secret key entry.

Returns:

Secret key.

process

protected abstract byte[] process(CiphertextHeader header,
 boolean mode,
 byte[] input)

Processes the given data under the action of the cipher.

Parameters:

header - Ciphertext header.

mode - True for encryption; false for decryption.

input - Data to process by cipher.

Returns:

Ciphertext data under encryption, plaintext data under decryption.

process

protected abstract void process(CiphertextHeader header,
 boolean mode,
 InputStream input,
 OutputStream output)

Processes the given data under the action of the cipher.

Parameters:

header - Ciphertext header.

mode - True for encryption; false for decryption.

input - Stream containing input data.

output - Stream that receives output of cipher.