javax.crypto: public class: SecretKeyFactory

javax.crypto
public class: SecretKeyFactory [javadoc | source]

java.lang.Object
   javax.crypto.SecretKeyFactory

This class represents a factory for secret keys.

Key factories are used to convert keys (opaque cryptographic keys of type Key) into key specifications (transparent representations of the underlying key material), and vice versa. Secret key factories operate only on secret (symmetric) keys.

Key factories are bi-directional, i.e., they allow to build an opaque key object from a given key specification (key material), or to retrieve the underlying key material of a key object in a suitable format.

Application developers should refer to their provider's documentation to find out which key specifications are supported by the generateSecret and getKeySpec methods. For example, the DES secret-key factory supplied by the "SunJCE" provider supports DESKeySpec as a transparent representation of DES keys, and that provider's secret-key factory for Triple DES keys supports DESedeKeySpec as a transparent representation of Triple DES keys.

Every implementation of the Java platform is required to support the following standard SecretKeyFactory algorithms:

DES
DESede

These algorithms are described in the SecretKeyFactory section of the Java Cryptography Architecture Standard Algorithm Name Documentation. Consult the release documentation for your implementation to see if any other algorithms are supported.

Also see:

SecretKey

javax.crypto.spec.DESKeySpec

javax.crypto.spec.DESedeKeySpec

javax.crypto.spec.PBEKeySpec

author: Jan - Luehe

since: 1.4 -

Constructor:

Constructor:
protected SecretKeyFactory(SecretKeyFactorySpi keyFacSpi, Provider provider, String algorithm) { this.spi = keyFacSpi; this.provider = provider; this.algorithm = algorithm; } Creates a SecretKeyFactory object. Parameters: `keyFacSpi` - the delegate `provider` - the provider `algorithm` - the secret-key algorithm

 protected SecretKeyFactory(SecretKeyFactorySpi keyFacSpi,
    Provider provider,
    String algorithm) {
        this.spi = keyFacSpi;
        this.provider = provider;
        this.algorithm = algorithm;
}

Creates a SecretKeyFactory object.

Parameters:

keyFacSpi - the delegate

provider - the provider

algorithm - the secret-key algorithm

Method from javax.crypto.SecretKeyFactory Summary:
generateSecret, getAlgorithm, getInstance, getInstance, getInstance, getKeySpec, getProvider, translateKey

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from javax.crypto.SecretKeyFactory Detail:
public final SecretKey generateSecret(KeySpec keySpec) throws InvalidKeySpecException { if (serviceIterator == null) { return spi.engineGenerateSecret(keySpec); } Exception failure = null; SecretKeyFactorySpi mySpi = spi; do { try { return mySpi.engineGenerateSecret(keySpec); } catch (Exception e) { if (failure == null) { failure = e; } mySpi = nextSpi(mySpi); } } while (mySpi != null); if (failure instanceof InvalidKeySpecException) { throw (InvalidKeySpecException)failure; } throw new InvalidKeySpecException ("Could not generate secret key", failure); } Generates a `SecretKey` object from the provided key specification (key material).
public final String getAlgorithm() { return this.algorithm; } Returns the algorithm name of this `SecretKeyFactory` object. This is the same name that was specified in one of the `getInstance` calls that created this `SecretKeyFactory` object.
public static final SecretKeyFactory getInstance(String algorithm) throws NoSuchAlgorithmException { return new SecretKeyFactory(algorithm); } Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm. This method traverses the list of registered security Providers, starting with the most preferred Provider. A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi implementation from the first Provider that supports the specified algorithm is returned. Note that the list of registered providers may be retrieved via the Security.getProviders() method.
public static final SecretKeyFactory getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException { Instance instance = JceSecurity.getInstance("SecretKeyFactory", SecretKeyFactorySpi.class, algorithm, provider); return new SecretKeyFactory((SecretKeyFactorySpi)instance.impl, instance.provider, algorithm); } Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm. A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi implementation from the specified provider is returned. The specified provider must be registered in the security provider list. Note that the list of registered providers may be retrieved via the Security.getProviders() method.
public static final SecretKeyFactory getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException { Instance instance = JceSecurity.getInstance("SecretKeyFactory", SecretKeyFactorySpi.class, algorithm, provider); return new SecretKeyFactory((SecretKeyFactorySpi)instance.impl, instance.provider, algorithm); } Returns a `SecretKeyFactory` object that converts secret keys of the specified algorithm. A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.
public final KeySpec getKeySpec(SecretKey key, Class keySpec) throws InvalidKeySpecException { if (serviceIterator == null) { return spi.engineGetKeySpec(key, keySpec); } Exception failure = null; SecretKeyFactorySpi mySpi = spi; do { try { return mySpi.engineGetKeySpec(key, keySpec); } catch (Exception e) { if (failure == null) { failure = e; } mySpi = nextSpi(mySpi); } } while (mySpi != null); if (failure instanceof InvalidKeySpecException) { throw (InvalidKeySpecException)failure; } throw new InvalidKeySpecException ("Could not get key spec", failure); } Returns a specification (key material) of the given key object in the requested format.
public final Provider getProvider() { synchronized (lock) { // disable further failover after this call serviceIterator = null; return provider; } } Returns the provider of this `SecretKeyFactory` object.
public final SecretKey translateKey(SecretKey key) throws InvalidKeyException { if (serviceIterator == null) { return spi.engineTranslateKey(key); } Exception failure = null; SecretKeyFactorySpi mySpi = spi; do { try { return mySpi.engineTranslateKey(key); } catch (Exception e) { if (failure == null) { failure = e; } mySpi = nextSpi(mySpi); } } while (mySpi != null); if (failure instanceof InvalidKeyException) { throw (InvalidKeyException)failure; } throw new InvalidKeyException ("Could not translate key", failure); } Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this secret-key factory.

Method from javax.crypto.SecretKeyFactory Detail:

 public final SecretKey generateSecret(KeySpec keySpec) throws InvalidKeySpecException {
        if (serviceIterator == null) {
            return spi.engineGenerateSecret(keySpec);
        }
        Exception failure = null;
        SecretKeyFactorySpi mySpi = spi;
        do {
            try {
                return mySpi.engineGenerateSecret(keySpec);
            } catch (Exception e) {
                if (failure == null) {
                    failure = e;
                }
                mySpi = nextSpi(mySpi);
            }
        } while (mySpi != null);
        if (failure instanceof InvalidKeySpecException) {
            throw (InvalidKeySpecException)failure;
        }
        throw new InvalidKeySpecException
                ("Could not generate secret key", failure);
}

SecretKey

 public final String getAlgorithm() {
        return this.algorithm;
}

SecretKeyFactory

This is the same name that was specified in one of the getInstance calls that created this SecretKeyFactory object.

 public static final SecretKeyFactory getInstance(String algorithm) throws NoSuchAlgorithmException {
        return new SecretKeyFactory(algorithm);
}

SecretKeyFactory

This method traverses the list of registered security Providers, starting with the most preferred Provider. A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi implementation from the first Provider that supports the specified algorithm is returned.

Note that the list of registered providers may be retrieved via the Security.getProviders() method.

 public static final SecretKeyFactory getInstance(String algorithm,
    String provider) throws NoSuchAlgorithmException, NoSuchProviderException {
        Instance instance = JceSecurity.getInstance("SecretKeyFactory",
                SecretKeyFactorySpi.class, algorithm, provider);
        return new SecretKeyFactory((SecretKeyFactorySpi)instance.impl,
                instance.provider, algorithm);
}

SecretKeyFactory

A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi implementation from the specified provider is returned. The specified provider must be registered in the security provider list.

Note that the list of registered providers may be retrieved via the Security.getProviders() method.

 public static final SecretKeyFactory getInstance(String algorithm,
    Provider provider) throws NoSuchAlgorithmException {
        Instance instance = JceSecurity.getInstance("SecretKeyFactory",
                SecretKeyFactorySpi.class, algorithm, provider);
        return new SecretKeyFactory((SecretKeyFactorySpi)instance.impl,
                instance.provider, algorithm);
}

SecretKeyFactory

A new SecretKeyFactory object encapsulating the SecretKeyFactorySpi implementation from the specified Provider object is returned. Note that the specified Provider object does not have to be registered in the provider list.

 public final KeySpec getKeySpec(SecretKey key,
    Class keySpec) throws InvalidKeySpecException {
        if (serviceIterator == null) {
            return spi.engineGetKeySpec(key, keySpec);
        }
        Exception failure = null;
        SecretKeyFactorySpi mySpi = spi;
        do {
            try {
                return mySpi.engineGetKeySpec(key, keySpec);
            } catch (Exception e) {
                if (failure == null) {
                    failure = e;
                }
                mySpi = nextSpi(mySpi);
            }
        } while (mySpi != null);
        if (failure instanceof InvalidKeySpecException) {
            throw (InvalidKeySpecException)failure;
        }
        throw new InvalidKeySpecException
                ("Could not get key spec", failure);
}

Returns a specification (key material) of the given key object in the requested format.

 public final Provider getProvider() {
        synchronized (lock) {
            // disable further failover after this call
            serviceIterator = null;
            return provider;
        }
}

SecretKeyFactory

 public final SecretKey translateKey(SecretKey key) throws InvalidKeyException {
        if (serviceIterator == null) {
            return spi.engineTranslateKey(key);
        }
        Exception failure = null;
        SecretKeyFactorySpi mySpi = spi;
        do {
            try {
                return mySpi.engineTranslateKey(key);
            } catch (Exception e) {
                if (failure == null) {
                    failure = e;
                }
                mySpi = nextSpi(mySpi);
            }
        } while (mySpi != null);
        if (failure instanceof InvalidKeyException) {
            throw (InvalidKeyException)failure;
        }
        throw new InvalidKeyException
                ("Could not translate key", failure);
}

Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this secret-key factory.