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      1 package org.bouncycastle.jcajce.provider.asymmetric.util;
      2 
      3 import java.math.BigInteger;
      4 import java.security.SignatureException;
      5 import java.security.SignatureSpi;
      6 import java.security.spec.AlgorithmParameterSpec;
      7 
      8 import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;
      9 import org.bouncycastle.asn1.x509.X509ObjectIdentifiers;
     10 import org.bouncycastle.crypto.DSA;
     11 import org.bouncycastle.crypto.Digest;
     12 
     13 public abstract class DSABase
     14     extends SignatureSpi
     15     implements PKCSObjectIdentifiers, X509ObjectIdentifiers
     16 {
     17     protected Digest digest;
     18     protected DSA                     signer;
     19     protected DSAEncoder              encoder;
     20 
     21     protected DSABase(
     22         Digest                  digest,
     23         DSA                     signer,
     24         DSAEncoder              encoder)
     25     {
     26         this.digest = digest;
     27         this.signer = signer;
     28         this.encoder = encoder;
     29     }
     30 
     31     protected void engineUpdate(
     32         byte    b)
     33         throws SignatureException
     34     {
     35         digest.update(b);
     36     }
     37 
     38     protected void engineUpdate(
     39         byte[]  b,
     40         int     off,
     41         int     len)
     42         throws SignatureException
     43     {
     44         digest.update(b, off, len);
     45     }
     46 
     47     protected byte[] engineSign()
     48         throws SignatureException
     49     {
     50         byte[]  hash = new byte[digest.getDigestSize()];
     51 
     52         digest.doFinal(hash, 0);
     53 
     54         try
     55         {
     56             BigInteger[]    sig = signer.generateSignature(hash);
     57 
     58             return encoder.encode(sig[0], sig[1]);
     59         }
     60         catch (Exception e)
     61         {
     62             throw new SignatureException(e.toString());
     63         }
     64     }
     65 
     66     protected boolean engineVerify(
     67         byte[]  sigBytes)
     68         throws SignatureException
     69     {
     70         byte[]  hash = new byte[digest.getDigestSize()];
     71 
     72         digest.doFinal(hash, 0);
     73 
     74         BigInteger[]    sig;
     75 
     76         try
     77         {
     78             sig = encoder.decode(sigBytes);
     79         }
     80         catch (Exception e)
     81         {
     82             throw new SignatureException("error decoding signature bytes.");
     83         }
     84 
     85         return signer.verifySignature(hash, sig[0], sig[1]);
     86     }
     87 
     88     protected void engineSetParameter(
     89         AlgorithmParameterSpec params)
     90     {
     91         throw new UnsupportedOperationException("engineSetParameter unsupported");
     92     }
     93 
     94     /**
     95      * @deprecated replaced with <a href = "#engineSetParameter(java.security.spec.AlgorithmParameterSpec)">
     96      */
     97     protected void engineSetParameter(
     98         String  param,
     99         Object  value)
    100     {
    101         throw new UnsupportedOperationException("engineSetParameter unsupported");
    102     }
    103 
    104     /**
    105      * @deprecated
    106      */
    107     protected Object engineGetParameter(
    108         String      param)
    109     {
    110         throw new UnsupportedOperationException("engineSetParameter unsupported");
    111     }
    112 }
    113