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package com.sun.crypto.provider;

import java.security.Key;
import java.security.PublicKey;
import java.security.PrivateKey;
import java.security.KeyFactorySpi;
import java.security.InvalidKeyException;
import java.security.spec.KeySpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.X509EncodedKeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import javax.crypto.spec.DHPublicKeySpec;
import javax.crypto.spec.DHPrivateKeySpec;
import javax.crypto.spec.DHParameterSpec;

This class implements the Diffie-Hellman key factory of the Sun provider.
Author:Jan Luehe
/** * This class implements the Diffie-Hellman key factory of the Sun provider. * * @author Jan Luehe * */
public final class DHKeyFactory extends KeyFactorySpi {
Empty constructor
/** * Empty constructor */
public DHKeyFactory() { }
Generates a public key object from the provided key specification (key material).
Params:
  • keySpec – the specification (key material) of the public key
Throws:
  • InvalidKeySpecException – if the given key specification is inappropriate for this key factory to produce a public key.
Returns:the public key
/** * Generates a public key object from the provided key specification * (key material). * * @param keySpec the specification (key material) of the public key * * @return the public key * * @exception InvalidKeySpecException if the given key specification * is inappropriate for this key factory to produce a public key. */
protected PublicKey engineGeneratePublic(KeySpec keySpec) throws InvalidKeySpecException { try { if (keySpec instanceof DHPublicKeySpec) { DHPublicKeySpec dhPubKeySpec = (DHPublicKeySpec)keySpec; return new DHPublicKey(dhPubKeySpec.getY(), dhPubKeySpec.getP(), dhPubKeySpec.getG()); } else if (keySpec instanceof X509EncodedKeySpec) { return new DHPublicKey (((X509EncodedKeySpec)keySpec).getEncoded()); } else { throw new InvalidKeySpecException ("Inappropriate key specification"); } } catch (InvalidKeyException e) { throw new InvalidKeySpecException ("Inappropriate key specification", e); } }
Generates a private key object from the provided key specification (key material).
Params:
  • keySpec – the specification (key material) of the private key
Throws:
  • InvalidKeySpecException – if the given key specification is inappropriate for this key factory to produce a private key.
Returns:the private key
/** * Generates a private key object from the provided key specification * (key material). * * @param keySpec the specification (key material) of the private key * * @return the private key * * @exception InvalidKeySpecException if the given key specification * is inappropriate for this key factory to produce a private key. */
protected PrivateKey engineGeneratePrivate(KeySpec keySpec) throws InvalidKeySpecException { try { if (keySpec instanceof DHPrivateKeySpec) { DHPrivateKeySpec dhPrivKeySpec = (DHPrivateKeySpec)keySpec; return new DHPrivateKey(dhPrivKeySpec.getX(), dhPrivKeySpec.getP(), dhPrivKeySpec.getG()); } else if (keySpec instanceof PKCS8EncodedKeySpec) { return new DHPrivateKey (((PKCS8EncodedKeySpec)keySpec).getEncoded()); } else { throw new InvalidKeySpecException ("Inappropriate key specification"); } } catch (InvalidKeyException e) { throw new InvalidKeySpecException ("Inappropriate key specification", e); } }
Returns a specification (key material) of the given key object in the requested format.
Params:
  • key – the key
  • keySpec – the requested format in which the key material shall be returned
Throws:
  • InvalidKeySpecException – if the requested key specification is inappropriate for the given key, or the given key cannot be processed (e.g., the given key has an unrecognized algorithm or format).
Returns:the underlying key specification (key material) in the requested format
/** * Returns a specification (key material) of the given key object * in the requested format. * * @param key the key * * @param keySpec the requested format in which the key material shall be * returned * * @return the underlying key specification (key material) in the * requested format * * @exception InvalidKeySpecException if the requested key specification is * inappropriate for the given key, or the given key cannot be processed * (e.g., the given key has an unrecognized algorithm or format). */
protected <T extends KeySpec> T engineGetKeySpec(Key key, Class<T> keySpec) throws InvalidKeySpecException { DHParameterSpec params; if (key instanceof javax.crypto.interfaces.DHPublicKey) { if (DHPublicKeySpec.class.isAssignableFrom(keySpec)) { javax.crypto.interfaces.DHPublicKey dhPubKey = (javax.crypto.interfaces.DHPublicKey) key; params = dhPubKey.getParams(); return keySpec.cast(new DHPublicKeySpec(dhPubKey.getY(), params.getP(), params.getG())); } else if (X509EncodedKeySpec.class.isAssignableFrom(keySpec)) { return keySpec.cast(new X509EncodedKeySpec(key.getEncoded())); } else { throw new InvalidKeySpecException ("Inappropriate key specification"); } } else if (key instanceof javax.crypto.interfaces.DHPrivateKey) { if (DHPrivateKeySpec.class.isAssignableFrom(keySpec)) { javax.crypto.interfaces.DHPrivateKey dhPrivKey = (javax.crypto.interfaces.DHPrivateKey)key; params = dhPrivKey.getParams(); return keySpec.cast(new DHPrivateKeySpec(dhPrivKey.getX(), params.getP(), params.getG())); } else if (PKCS8EncodedKeySpec.class.isAssignableFrom(keySpec)) { return keySpec.cast(new PKCS8EncodedKeySpec(key.getEncoded())); } else { throw new InvalidKeySpecException ("Inappropriate key specification"); } } else { throw new InvalidKeySpecException("Inappropriate key type"); } }
Translates a key object, whose provider may be unknown or potentially untrusted, into a corresponding key object of this key factory.
Params:
  • key – the key whose provider is unknown or untrusted
Throws:
Returns:the translated key
/** * Translates a key object, whose provider may be unknown or potentially * untrusted, into a corresponding key object of this key factory. * * @param key the key whose provider is unknown or untrusted * * @return the translated key * * @exception InvalidKeyException if the given key cannot be processed by * this key factory. */
protected Key engineTranslateKey(Key key) throws InvalidKeyException { try { if (key instanceof javax.crypto.interfaces.DHPublicKey) { // Check if key originates from this factory if (key instanceof com.sun.crypto.provider.DHPublicKey) { return key; } // Convert key to spec DHPublicKeySpec dhPubKeySpec = engineGetKeySpec(key, DHPublicKeySpec.class); // Create key from spec, and return it return engineGeneratePublic(dhPubKeySpec); } else if (key instanceof javax.crypto.interfaces.DHPrivateKey) { // Check if key originates from this factory if (key instanceof com.sun.crypto.provider.DHPrivateKey) { return key; } // Convert key to spec DHPrivateKeySpec dhPrivKeySpec = engineGetKeySpec(key, DHPrivateKeySpec.class); // Create key from spec, and return it return engineGeneratePrivate(dhPrivKeySpec); } else { throw new InvalidKeyException("Wrong algorithm type"); } } catch (InvalidKeySpecException e) { throw new InvalidKeyException("Cannot translate key", e); } } }