package org.bouncycastle.jcajce.provider.asymmetric.dsa;
import java.io.IOException;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.DSAParameterSpec;
import java.security.spec.InvalidParameterSpecException;
import org.bouncycastle.asn1.ASN1Encoding;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.x509.DSAParameter;
public class AlgorithmParametersSpi
extends java.security.AlgorithmParametersSpi
{
DSAParameterSpec currentSpec;
protected boolean isASN1FormatString(String format)
{
return format == null || format.equals("ASN.1");
}
protected AlgorithmParameterSpec engineGetParameterSpec(
Class paramSpec)
throws InvalidParameterSpecException
{
if (paramSpec == null)
{
throw new NullPointerException("argument to getParameterSpec must not be null");
}
return localEngineGetParameterSpec(paramSpec);
}
/**
* Return the X.509 ASN.1 structure DSAParameter.
* <p/>
* <pre>
* DSAParameter ::= SEQUENCE {
* prime INTEGER, -- p
* subprime INTEGER, -- q
* base INTEGER, -- g}
* </pre>
*/
protected byte[] engineGetEncoded()
{
DSAParameter dsaP = new DSAParameter(currentSpec.getP(), currentSpec.getQ(), currentSpec.getG());
try
{
return dsaP.getEncoded(ASN1Encoding.DER);
}
catch (IOException e)
{
throw new RuntimeException("Error encoding DSAParameters");
}
}
protected byte[] engineGetEncoded(
String format)
{
if (isASN1FormatString(format))
{
return engineGetEncoded();
}
return null;
}
protected AlgorithmParameterSpec localEngineGetParameterSpec(
Class paramSpec)
throws InvalidParameterSpecException
{
if (paramSpec == DSAParameterSpec.class)
{
return currentSpec;
}
throw new InvalidParameterSpecException("unknown parameter spec passed to DSA parameters object.");
}
protected void engineInit(
AlgorithmParameterSpec paramSpec)
throws InvalidParameterSpecException
{
if (!(paramSpec instanceof DSAParameterSpec))
{
throw new InvalidParameterSpecException("DSAParameterSpec required to initialise a DSA algorithm parameters object");
}
this.currentSpec = (DSAParameterSpec)paramSpec;
}
protected void engineInit(
byte[] params)
throws IOException
{
try
{
DSAParameter dsaP = DSAParameter.getInstance(ASN1Primitive.fromByteArray(params));
currentSpec = new DSAParameterSpec(dsaP.getP(), dsaP.getQ(), dsaP.getG());
}
catch (ClassCastException e)
{
throw new IOException("Not a valid DSA Parameter encoding.");
}
catch (ArrayIndexOutOfBoundsException e)
{
throw new IOException("Not a valid DSA Parameter encoding.");
}
}
protected void engineInit(
byte[] params,
String format)
throws IOException
{
if (isASN1FormatString(format) || format.equalsIgnoreCase("X.509"))
{
engineInit(params);
}
else
{
throw new IOException("Unknown parameter format " + format);
}
}
protected String engineToString()
{
return "DSA Parameters";
}
}