I have PEM format file, How can verify the signature in Java, as I followed http://download.oracle.com/javase/tutorial/security/apisign/versig.html but found that Java doesnt support PEM

解决方案

You can read a certificate in a PEM file using BouncyCastle's PEMReader. If the content is an X.509 certificate, you should get an instance of X509Certificate and verify it as you want from there.

EDIT: Here is what the code should look like (not tried):

// The key with which you want to verify the cert.

// This is probably a CA certificate's public key.

PublicKey publicKey = ...;

PEMReader reader = new PEMReader(new FileReader("/path/to/file.pem"));

Object pemObject = reader.readObject();

if (pemObject instanceof X509Certificate) {

X509Certificate cert = (X509Certificate)pemObject;

cert.checkValidity(); // to check it's valid in time

cert.verify(publicKey); // verify the sig. using the issuer's public key

}

(Of course, as with any I/O operations, you'll need to close the reader perhaps with try/finally.)

Note that checkValidity and verify don't return anything: instead, they throw exceptions if when they fail.