javax.crypto

Class KeyGenerator

java.lang.Object

javax.crypto.KeyGenerator

public class KeyGenerator
extends Object

A generic producer of keys for symmetric cryptography. The keys returned may be simple wrappers around byte arrays, or, if the target cipher requires them, more complex objects.

Since:

1.4

See Also:

Cipher, Mac

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	KeyGenerator(KeyGeneratorSpi kgSpi, Provider provider, String algorithm) Create a new key generator.

Method Summary

Methods

Modifier and Type	Method and Description
SecretKey	generateKey() Generate a key.
String	getAlgorithm() Return the name of this key generator.
static KeyGenerator	getInstance(String algorithm) Create a new key generator, returning the first available implementation.
static KeyGenerator	getInstance(String algorithm, Provider provider) Create a new key generator from the supplied provider.
static KeyGenerator	getInstance(String algorithm, String provider) Create a new key generator from the named provider.
Provider	getProvider() Return the provider of the underlying implementation.
void	init(AlgorithmParameterSpec params) Initialize this key generator with a set of parameters; the highest-priority SecureRandom implementation will be used.
void	init(AlgorithmParameterSpec params, SecureRandom random) Initialize this key generator with a set of parameters and a source of randomness.
void	init(int keySize) Initialize this key generator with a key size (in bits); the highest-priority SecureRandom implementation will be used.
void	init(int keySize, SecureRandom random) Initialize this key generator with a key size (in bits) and a source of randomness.
void	init(SecureRandom random) Initialize this key generator with a source of randomness.

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyGenerator

protected KeyGenerator(KeyGeneratorSpi kgSpi,
            Provider provider,
            String algorithm)

Create a new key generator.

Parameters:

kgSpi - The underlying generator.

provider - The provider of this implementation.

algorithm - The algorithm's name.

Method Detail

getInstance

public static final KeyGenerator getInstance(String algorithm)
                                      throws NoSuchAlgorithmException

Create a new key generator, returning the first available implementation.

Parameters:

algorithm - The generator algorithm name.

Throws:

NoSuchAlgorithmException - If the specified algorithm does not exist.

IllegalArgumentException - if algorithm is null or is an empty string.

getInstance

public static final KeyGenerator getInstance(String algorithm,
                       String provider)
                                      throws NoSuchAlgorithmException,
                                             NoSuchProviderException

Create a new key generator from the named provider.

Parameters:

algorithm - The generator algorithm name.

provider - The name of the provider to use.

Returns:

An appropriate key generator, if found.

Throws:

NoSuchAlgorithmException - If the specified algorithm is not implemented by the named provider.

NoSuchProviderException - If the named provider does not exist.

IllegalArgumentException - if either algorithm or provider is null, or if algorithm is an empty string.

getInstance

public static final KeyGenerator getInstance(String algorithm,
                       Provider provider)
                                      throws NoSuchAlgorithmException

Create a new key generator from the supplied provider.

Parameters:

algorithm - The generator algorithm name.

provider - The provider to use.

Returns:

An appropriate key generator, if found.

Throws:

NoSuchAlgorithmException - If the specified algorithm is not implemented by the provider.

IllegalArgumentException - if either algorithm or provider is null, or if algorithm is an empty string.

generateKey

public final SecretKey generateKey()

Generate a key.

Returns:

The new key.

getAlgorithm

public final String getAlgorithm()

Return the name of this key generator.

Returns:

The algorithm name.

getProvider

public final Provider getProvider()

Return the provider of the underlying implementation.

Returns:

The provider.

init

public final void init(AlgorithmParameterSpec params)
                throws InvalidAlgorithmParameterException

Initialize this key generator with a set of parameters; the highest-priority SecureRandom implementation will be used.

Parameters:

params - The algorithm parameters.

Throws:

InvalidAlgorithmParameterException - If the supplied parameters are inapproprate.

init

public final void init(AlgorithmParameterSpec params,
        SecureRandom random)
                throws InvalidAlgorithmParameterException

Initialize this key generator with a set of parameters and a source of randomness.

Parameters:

params - The algorithm parameters.

random - The source of randomness.

Throws:

InvalidAlgorithmParameterException - If the supplied parameters are inapproprate.

init

public final void init(int keySize)

Initialize this key generator with a key size (in bits); the highest-priority SecureRandom implementation will be used.

Parameters:

keySize - The target key size, in bits.

Throws:

InvalidParameterException - If the key size is unsupported.

init

public final void init(int keySize,
        SecureRandom random)

Initialize this key generator with a key size (in bits) and a source of randomness.

Parameters:

keySize - The target key size, in bits.

random - The source of randomness.

Throws:

InvalidAlgorithmParameterException - If the key size is unsupported.

init

public final void init(SecureRandom random)

Initialize this key generator with a source of randomness. The implementation-specific default parameters (such as key size) will be used.

Parameters:

random - The source of randomness.