1 files changed, 112 insertions, 0 deletions
diff --git a/prov/src/main/java/org/spongycastle/jcajce/provider/asymmetric/util/DSABase.java b/prov/src/main/java/org/spongycastle/jcajce/provider/asymmetric/util/DSABase.java
new file mode 100644
index 00000000..0f659b2c
--- /dev/null
+++ b/prov/src/main/java/org/spongycastle/jcajce/provider/asymmetric/util/DSABase.java
@@ -0,0 +1,112 @@
+package org.spongycastle.jcajce.provider.asymmetric.util;
+
+import java.math.BigInteger;
+import java.security.SignatureException;
+import java.security.SignatureSpi;
+import java.security.spec.AlgorithmParameterSpec;
+
+import org.spongycastle.asn1.pkcs.PKCSObjectIdentifiers;
+import org.spongycastle.asn1.x509.X509ObjectIdentifiers;
+import org.spongycastle.crypto.DSA;
+import org.spongycastle.crypto.Digest;
+
+public abstract class DSABase
+    extends SignatureSpi
+    implements PKCSObjectIdentifiers, X509ObjectIdentifiers
+{
+    protected Digest digest;
+    protected DSA                     signer;
+    protected DSAEncoder              encoder;
+
+    protected DSABase(
+        Digest                  digest,
+        DSA                     signer,
+        DSAEncoder              encoder)
+    {
+        this.digest = digest;
+        this.signer = signer;
+        this.encoder = encoder;
+    }
+
+    protected void engineUpdate(
+        byte    b)
+        throws SignatureException
+    {
+        digest.update(b);
+    }
+
+    protected void engineUpdate(
+        byte[]  b,
+        int     off,
+        int     len) 
+        throws SignatureException
+    {
+        digest.update(b, off, len);
+    }
+
+    protected byte[] engineSign()
+        throws SignatureException
+    {
+        byte[]  hash = new byte[digest.getDigestSize()];
+
+        digest.doFinal(hash, 0);
+
+        try
+        {
+            BigInteger[]    sig = signer.generateSignature(hash);
+
+            return encoder.encode(sig[0], sig[1]);
+        }
+        catch (Exception e)
+        {
+            throw new SignatureException(e.toString());
+        }
+    }
+
+    protected boolean engineVerify(
+        byte[]  sigBytes) 
+        throws SignatureException
+    {
+        byte[]  hash = new byte[digest.getDigestSize()];
+
+        digest.doFinal(hash, 0);
+
+        BigInteger[]    sig;
+
+        try
+        {
+            sig = encoder.decode(sigBytes);
+        }
+        catch (Exception e)
+        {
+            throw new SignatureException("error decoding signature bytes.");
+        }
+
+        return signer.verifySignature(hash, sig[0], sig[1]);
+    }
+
+    protected void engineSetParameter(
+        AlgorithmParameterSpec params)
+    {
+        throw new UnsupportedOperationException("engineSetParameter unsupported");
+    }
+
+    /**
+     * @deprecated replaced with <a href = "#engineSetParameter(java.security.spec.AlgorithmParameterSpec)">
+     */
+    protected void engineSetParameter(
+        String  param,
+        Object  value)
+    {
+        throw new UnsupportedOperationException("engineSetParameter unsupported");
+    }
+
+    /**
+     * @deprecated
+     */
+    protected Object engineGetParameter(
+        String      param)
+    {
+        throw new UnsupportedOperationException("engineSetParameter unsupported");
+    }
+}