Java Requires Chilkat v11.0.0+

Duplicate openssl dgst -md5 -sign myKey.pem something.txt | openssl enc -base64 -A

See more RSA Examples

Demonstrates how to duplicate the creation of an RSA signature produced by this OpenSSL command:

openssl dgst -md5 -sign myKey.pem something.txt | openssl enc -base64 -A

Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.PrivateKey;
import com.chilkatsoft.chilkat2.Rsa;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example assumes the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        PrivateKey pkey = new PrivateKey();

        // Load the private key from an RSA PEM file:
        pkey.loadPemFile("myKey.pem");

        Rsa rsa = new Rsa();

        // Import the private key into the RSA component:
        try {
            rsa.usePrivateKey(pkey);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // OpenSSL uses BigEndian byte ordering:
        rsa.setLittleEndian(false);

        // The resulting signature will be a Base64 string:
        rsa.setEncodingMode("base64");

        // For simplicity, we're not loading
        // the data to be signed from a file.  We are instead simply
        // using a literal string value.
        String strData = "This is the text to be signed.";

        // Hash the input using MD5, and then sign the hash:
        // Other valid hash algorithm choices are "md2" and "sha-1".
        String base64Sig = rsa.signStringENC(strData, "md5");

        System.out.println(base64Sig);

        System.out.println("Success!");
    }
}