Java Requires Chilkat v11.0.0+

Duplicate openssl dgst -sha256 -sign private.pem -out sha256.sig in.dat

See more OpenSSL Examples

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -sign private.pem -out sha256.sig in.dat

The in.dat file can contain text or binary data of any type. The OpenSSL command does the following:

1. Creates a SHA256 digest of the contents of the input file
2. Signs the SHA256 digest using the private key.

Chilkat2 Java

import com.chilkatsoft.chilkat2.BinData;
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 requires 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 PEM file:
        try {
            pkey.loadPemFile("private.pem");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        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 big-endian.
        rsa.setLittleEndian(false);

        // Load the file to be signed.
        BinData bdFileData = new BinData();
        bdFileData.loadFile("in.dat");

        BinData bdSig = new BinData();
        try {
            rsa.signBd(bdFileData, "sha256", bdSig);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Save the binary signature to a file.
        try {
            bdSig.writeFile("signature.sig");
        } catch (ChilkatException e) {
            System.out.println("Failed to write signature.sig.");
            return;
        }

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