Java Security

I have trouble decrypting a .p7m file.

Can someone help me?

What I try to do is getting the key from the certificate file (xxx.pks)
Use the key to decrypted the .p7m file and write to another file.

I can retrieve the key from the certificate.
However, I cannot decrypt the .p7m file.

Thanks.

Here is my code:

//get receiver cert
X509Certificate receiverCert = (X509Certificate)keystore.getCertificate(alias);

//get key
Key key = keystore.getKey(alias, password.toCharArray());

Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, key);

File p7mFile = new File("C:\\temp\\test.p7m");
DataInputStream input = new DataInputStream(new FileInputStream(p7mFile ));


File out = new File("C:\\temp\\out");
FileOutputStream fotest= new FileOutputStream(out);

try {
byte[] data = new byte[1024];
int read;

try {
while((read = input.read(data)) >= 0) {
fotest.write(cipher.update(data,0, read));

}

} finally {
fotest.write(cipher.doFinal());
fotest.close();
}

Edited by: Jenny_Run on Apr 23, 2009 12:25 PM