Bouncy Castle : PEMReader => PEMParser

Question

With a PEM certificate like

-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: AES-256-CBC,B9846B5D1803E.....

using BC 1.46,

Answer 1

I just needed to solve the same problem and found no answer. So I spent some time studying BC API and found a solution which works for me. I needed to read the private key from file so there is privateKeyFileName parameter instead pemString parameter in the myFunc method.

Using BC 1.48 and PEMParser:

int myFunc(String privateKeyFileName, char [] password) {
     File privateKeyFile = new File(privateKeyFileName); // private key file in PEM format
     PEMParser pemParser = new PEMParser(new FileReader(privateKeyFile));
     Object object = pemParser.readObject();
     PEMDecryptorProvider decProv = new JcePEMDecryptorProviderBuilder().build(password);
     JcaPEMKeyConverter converter = new JcaPEMKeyConverter().setProvider("BC");
     KeyPair kp;
     if (object instanceof PEMEncryptedKeyPair) {
        System.out.println("Encrypted key - we will use provided password");
        kp = converter.getKeyPair(((PEMEncryptedKeyPair) object).decryptKeyPair(decProv));
    } else {
        System.out.println("Unencrypted key - no password needed");
        kp = converter.getKeyPair((PEMKeyPair) object);
    }
}