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package com.sun.crypto.provider;

import java.security.SecureRandom;
import java.security.InvalidParameterException;
import java.security.InvalidAlgorithmParameterException;
import java.security.spec.AlgorithmParameterSpec;
import javax.crypto.KeyGeneratorSpi;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

This class generates a secret key for use with the HMAC-MD5 algorithm.
Author:Jan Luehe
/** * This class generates a secret key for use with the HMAC-MD5 algorithm. * * @author Jan Luehe * */
public final class HmacMD5KeyGenerator extends KeyGeneratorSpi { private SecureRandom random = null; private int keysize = 64; // default keysize (in number of bytes)
Empty constructor
/** * Empty constructor */
public HmacMD5KeyGenerator() { }
Initializes this key generator.
Params:
  • random – the source of randomness for this generator
/** * Initializes this key generator. * * @param random the source of randomness for this generator */
protected void engineInit(SecureRandom random) { this.random = random; }
Initializes this key generator with the specified parameter set and a user-provided source of randomness.
Params:
  • params – the key generation parameters
  • random – the source of randomness for this key generator
Throws:
/** * Initializes this key generator with the specified parameter * set and a user-provided source of randomness. * * @param params the key generation parameters * @param random the source of randomness for this key generator * * @exception InvalidAlgorithmParameterException if <code>params</code> is * inappropriate for this key generator */
protected void engineInit(AlgorithmParameterSpec params, SecureRandom random) throws InvalidAlgorithmParameterException { throw new InvalidAlgorithmParameterException ("HMAC-MD5 key generation does not take any parameters"); }
Initializes this key generator for a certain keysize, using the given source of randomness.
Params:
  • keysize – the keysize. This is an algorithm-specific metric specified in number of bits.
  • random – the source of randomness for this key generator
/** * Initializes this key generator for a certain keysize, using the given * source of randomness. * * @param keysize the keysize. This is an algorithm-specific * metric specified in number of bits. * @param random the source of randomness for this key generator */
protected void engineInit(int keysize, SecureRandom random) { this.keysize = (keysize+7) / 8; this.engineInit(random); }
Generates an HMAC-MD5 key.
Returns:the new HMAC-MD5 key
/** * Generates an HMAC-MD5 key. * * @return the new HMAC-MD5 key */
protected SecretKey engineGenerateKey() { if (this.random == null) { this.random = SunJCE.getRandom(); } byte[] keyBytes = new byte[this.keysize]; this.random.nextBytes(keyBytes); return new SecretKeySpec(keyBytes, "HmacMD5"); } }