Java Security

Hi,

I am working on digital signatures RSA. I have two issues/doubts :-D

1) In Java 1.5, the crypto specification talks abt API support for RSA PKCS using PKCS #1 v2.1 thru the PSS padding scheme for signatures - java.security.spec.PPSParameterSpec. So, how i understood it was, after i create signature object for RSA i have to use setParameter to set these PSSParameterSpec to my signature object. But when i run my code, i get the UnSupportedOperationException. Please help me in this regard.

The Exception message is

java.lang.UnsupportedOperationException
at java.security.SignatureSpi.engineSetParameter(SignatureSpi.java:306)
at java.security.Signature$Delegate.engineSetParameter(Signature.java:11
61)
at java.security.Signature.setParameter(Signature.java:794)
at rsapsSigning.main(rsapsSigning.java:22)

My source code for the same is:

public class rsapsSigning
{
public static void main(String a[])
{

try
{

String datafile = "C:\\old.txt";
PSSParameterSpec pss = PSSParameterSpec.DEFAULT;

Signature s = Signature.getInstance("SHA1withRSA");

/*initialise sugnature object with pss parameter for RSA*/
s.setParameter((AlgorithmParameterSpec)pss); //exception gets thrown at this point

KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(128); // 128 is the keysize.
KeyPair kp = kpg.generateKeyPair();
PublicKey pubk = kp.getPublic();
PrivateKey prvk = kp.getPrivate();

s.initSign(prvk);

FileInputStream fis = new FileInputStream(datafile);
byte[] dataBytes = new byte[1024];
int nread = fis.read(dataBytes);
while (nread > 0) {
s.update(dataBytes, 0, nread);
nread = fis.read(dataBytes);
};
byte[] sig = s.sign();

for(int i = 0;i <sig.length;i++)
{
System.out.println(sig);

}

}catch(Exception e)
{
e.printStackTrace();
}
}

}

2) One other method that i tried was, instead of using PSSParameterSpec class, while creating Signature object, crypto Spec of 1.5 talks abt the usage of "<digest>with<encryptionalgo>and<mgf>" in the getInstance() of Signature class. So going on these lines, i can as well give "SHA1withRSAandMGF1" which is precisely what has been described as the default value for RSA PSS. But when i give so directly, I get "NoSuchAlgorithmException". In fact, for a trial basis when i tried "MD5withSHA1andMGF1" (the example given in the crypto spec of 1.5) also, i get the same exception :-( :-(

java.security.NoSuchAlgorithmException: SHA1withRSAandMGF1 Signature not availab
le
at java.security.Signature.getInstance(Signature.java:208)
at pp.main(pp.java:18)

My code for this is:


public class pp
{
public static void main(String a[])
{

try
{

String datafile = "C:\\new.txt";

Signature s = Signature.getInstance("SHA1withRSAandMGF1"); //exception gets thrown here

System.out.println("SHA1withRSAandMGF1");
}
catch(Exception e)
{
e.printStackTrace();
}
}
}

I am sorry that my query seems so long. But i was just trying to tell all the cases that I have tried.

I would be grateful to any suggestions.

Best Rgds