BaseSecretKeyFactory.java

package org.spongycastle.jcajce.provider.symmetric.util;

import java.lang.reflect.Constructor;
import java.security.InvalidKeyException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;

import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactorySpi;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;

import org.spongycastle.asn1.DERObjectIdentifier;
import org.spongycastle.crypto.CipherParameters;
import org.spongycastle.crypto.params.DESParameters;
import org.spongycastle.crypto.params.KeyParameter;
import org.spongycastle.crypto.params.ParametersWithIV;

public class BaseSecretKeyFactory
    extends SecretKeyFactorySpi
    implements PBE
{
    protected String                algName;
    protected DERObjectIdentifier   algOid;

    protected BaseSecretKeyFactory(
        String algName,
        DERObjectIdentifier algOid)
    {
        this.algName = algName;
        this.algOid = algOid;
    }

    protected SecretKey engineGenerateSecret(
        KeySpec keySpec)
    throws InvalidKeySpecException
    {
        if (keySpec instanceof SecretKeySpec)
        {
            return (SecretKey)keySpec;
        }

        throw new InvalidKeySpecException("Invalid KeySpec");
    }

    protected KeySpec engineGetKeySpec(
        SecretKey key,
        Class keySpec)
    throws InvalidKeySpecException
    {
        if (keySpec == null)
        {
            throw new InvalidKeySpecException("keySpec parameter is null");
        }
        if (key == null)
        {
            throw new InvalidKeySpecException("key parameter is null");
        }
        
        if (SecretKeySpec.class.isAssignableFrom(keySpec))
        {
            return new SecretKeySpec(key.getEncoded(), algName);
        }

        try
        {
            Class[] parameters = { byte[].class };

            Constructor c = keySpec.getConstructor(parameters);
            Object[]    p = new Object[1];

            p[0] = key.getEncoded();

            return (KeySpec)c.newInstance(p);
        }
        catch (Exception e)
        {
            throw new InvalidKeySpecException(e.toString());
        }
    }

    protected SecretKey engineTranslateKey(
        SecretKey key)
    throws InvalidKeyException
    {
        if (key == null)
        {
            throw new InvalidKeyException("key parameter is null");
        }
        
        if (!key.getAlgorithm().equalsIgnoreCase(algName))
        {
            throw new InvalidKeyException("Key not of type " + algName + ".");
        }

        return new SecretKeySpec(key.getEncoded(), algName);
    }

    /*
     * classes that inherit from us
     */
    


    static public class DESPBEKeyFactory
        extends BaseSecretKeyFactory
    {
        private boolean forCipher;
        private int     scheme;
        private int     digest;
        private int     keySize;
        private int     ivSize;
        
        public DESPBEKeyFactory(
            String              algorithm,
            DERObjectIdentifier oid,
            boolean             forCipher,
            int                 scheme,
            int                 digest,
            int                 keySize,
            int                 ivSize)
        {
            super(algorithm, oid);
            
            this.forCipher = forCipher;
            this.scheme = scheme;
            this.digest = digest;
            this.keySize = keySize;
            this.ivSize = ivSize;
        }
    
        protected SecretKey engineGenerateSecret(
            KeySpec keySpec)
        throws InvalidKeySpecException
        {
            if (keySpec instanceof PBEKeySpec)
            {
                PBEKeySpec pbeSpec = (PBEKeySpec)keySpec;
                CipherParameters    param;
                
                if (pbeSpec.getSalt() == null)
                {
                    return new BCPBEKey(this.algName, this.algOid, scheme, digest, keySize, ivSize, pbeSpec, null);
                }
                
                if (forCipher)
                {
                    param = PBE.Util.makePBEParameters(pbeSpec, scheme, digest, keySize, ivSize);
                }
                else
                {
                    param = PBE.Util.makePBEMacParameters(pbeSpec, scheme, digest, keySize);
                }

                KeyParameter kParam;
                if (param instanceof ParametersWithIV)
                {
                    kParam = (KeyParameter)((ParametersWithIV)param).getParameters();
                }
                else
                {
                    kParam = (KeyParameter)param;
                }

                DESParameters.setOddParity(kParam.getKey());

                return new BCPBEKey(this.algName, this.algOid, scheme, digest, keySize, ivSize, pbeSpec, param);
            }
            
            throw new InvalidKeySpecException("Invalid KeySpec");
        }
    }
    
    static public class DES
        extends BaseSecretKeyFactory
    {
        public DES()
        {
            super("DES", null);
        }

        protected SecretKey engineGenerateSecret(
            KeySpec keySpec)
        throws InvalidKeySpecException
        {
            if (keySpec instanceof DESKeySpec)
            {
                DESKeySpec desKeySpec = (DESKeySpec)keySpec;
                return new SecretKeySpec(desKeySpec.getKey(), "DES");
            }

            return super.engineGenerateSecret(keySpec);
        }
    }
}