sdk/sources/android-25/javax/crypto/SecretKeyFactorySpi.java

   1 /*
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   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
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  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
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  25
  26 package javax.crypto;
  27
  28 import java.security.*;
  29 import java.security.spec.*;
  30
  31 /**
  32  * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
  33  * for the <code>SecretKeyFactory</code> class.
  34  * All the abstract methods in this class must be implemented by each
  35  * cryptographic service provider who wishes to supply the implementation
  36  * of a secret-key factory for a particular algorithm.
  37  *
  38  * <P> A provider should document all the key specifications supported by its
  39  * secret key factory.
  40  * For example, the DES secret-key factory supplied by the "SunJCE" provider
  41  * supports <code>DESKeySpec</code> as a transparent representation of DES
  42  * keys, and that provider's secret-key factory for Triple DES keys supports
  43  * <code>DESedeKeySpec</code> as a transparent representation of Triple DES
  44  * keys.
  45  *
  46  * @author Jan Luehe
  47  *
  48  * @see SecretKey
  49  * @see javax.crypto.spec.DESKeySpec
  50  * @see javax.crypto.spec.DESedeKeySpec
  51  * @since 1.4
  52  */
  53
  54 public abstract class SecretKeyFactorySpi {
  55
  56     /**
  57      * Generates a <code>SecretKey</code> object from the
  58      * provided key specification (key material).
  59      *
  60      * @param keySpec the specification (key material) of the secret key
  61      *
  62      * @return the secret key
  63      *
  64      * @exception InvalidKeySpecException if the given key specification
  65      * is inappropriate for this secret-key factory to produce a secret key.
  66      */
  67     protected abstract SecretKey engineGenerateSecret(KeySpec keySpec)
  68         throws InvalidKeySpecException;
  69
  70     /**
  71      * Returns a specification (key material) of the given key
  72      * object in the requested format.
  73      *
  74      * @param key the key
  75      *
  76      * @param keySpec the requested format in which the key material shall be
  77      * returned
  78      *
  79      * @return the underlying key specification (key material) in the
  80      * requested format
  81      *
  82      * @exception InvalidKeySpecException if the requested key specification is
  83      * inappropriate for the given key (e.g., the algorithms associated with
  84      * <code>key</code> and <code>keySpec</code> do not match, or
  85      * <code>key</code> references a key on a cryptographic hardware device
  86      * whereas <code>keySpec</code> is the specification of a software-based
  87      * key), or the given key cannot be dealt with
  88      * (e.g., the given key has an algorithm or format not supported by this
  89      * secret-key factory).
  90      */
  91     protected abstract KeySpec engineGetKeySpec(SecretKey key, Class keySpec)
  92         throws InvalidKeySpecException;
  93
  94     /**
  95      * Translates a key object, whose provider may be unknown or
  96      * potentially untrusted, into a corresponding key object of this
  97      * secret-key factory.
  98      *
  99      * @param key the key whose provider is unknown or untrusted
 100      *
 101      * @return the translated key
 102      *
 103      * @exception InvalidKeyException if the given key cannot be processed
 104      * by this secret-key factory.
 105      */
 106     protected abstract SecretKey engineTranslateKey(SecretKey key)
 107         throws InvalidKeyException;
 108 }