Java in a Nutshell, 5th Edition [Electronic resources]

This class defines an API for translating a secret key between its opaque SecretKey representation and its transparent javax.crypto.SecretKeySpec representation. It is much like java.security.KeyFactory, except that it works with secret (or symmetric) keys rather than with public and private (asymmetric) keys. SecretKeyFactory is algorithm-independent and provider-based, so you must obtain a SecretKeyFactory object by calling one of the static getInstance( ) factory methods and specifying the name of the desired secret-key algorithm and, optionally, the name of the provider whose implementation is desired. In Java 5.0, the "SunJCE" provider provides SecretKeyFactory implementations for algorithms with the following names:

Once you have obtained a SecretKeyFactory, use generateSecret( ) to create a SecretKey from a java.security.spec.KeySpec (or its subclass, javax.crypto.spec.SecretKeySpec). Or call getKeySpec( ) to obtain a KeySpec for a Key object. Because there can be more than one suitable type of KeySpec, getKeySpec( ) requires a Class object to specify the type of the KeySpec to be created. See also DESKeySpec, DESedeKeySpec, and PBEKeySpec in the javax.crypto.spec package.

public class

SecretKeyFactory { // Protected Constructors protected

SecretKeyFactory (SecretKeyFactorySpi

keyFacSpi , java.security.Provider

provider , String

algorithm ); // Public Class Methods public static final SecretKeyFactory

getInstance (String

algorithm ) throws java.security.NoSuchAlgorithmException; public static final SecretKeyFactory

getInstance (String

algorithm , java.security.Provider

provider ) throws java.security.NoSuchAlgorithmException; public static final SecretKeyFactory

getInstance (String

algorithm , String

provider ) throws java.security.NoSuchAlgorithmException, java.security.NoSuchProviderException; // Public Instance Methods public final SecretKey

generateSecret (java.security.spec.KeySpec

keySpec ) throws java.security.spec.InvalidKeySpecException; public final String

getAlgorithm ( ); public final java.security.spec.KeySpec

getKeySpec (SecretKey

key , Class

keySpec ) throws java.security.spec.InvalidKeySpecException; public final java.security.Provider

getProvider ( ); public final SecretKey

translateKey (SecretKey

key ) throws java.security.InvalidKeyException; }