Java Requires Chilkat v11.0.0+

Demonstrate RSA Encrypt/Decrypt using BinData

See more RSA Examples

Demonstrates how to RSA encrypt and decrypt data contained in a Chilkat BinData object. Chilkat2 Java

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

public class ChilkatExample {

    public static void main(String[] args) {
        // The RSA public key is used for encryption, and the private key for decryption.

        // The public key's role is to make encryption accessible to anyone while ensuring that
        // only the private key holder can decrypt the messages.
        // The public key is designed to be widely distributed so anyone can use it to encrypt messages
        // intended for the owner of the private key.

        // Load our 2048-bit RSA public key.
        PublicKey pubKey = new PublicKey();
        // In all Chilkat methods expecting a path, you pass either absolute or relative paths.
        try {
            pubKey.loadFromFile("rsaKeys/myTestRsaPublic.pem");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        Rsa rsa = new Rsa();

        // Tell RSA to use the public key.
        rsa.usePublicKey(pubKey);

        // RSA encryption is for small amounts of data, on the order of 200 bytes or less.
        // The maximum number of bytes that can be RSA encrypted depends
        // on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
        // For specific limits, see: RSA Encryption Maximum Number of Bytes

        // Create some binary data to encrypt.
        BinData bd = new BinData();
        int i = 0;
        for (i = 0; i <= 49; i++) {
            bd.appendByte(i);
        }

        // Show the bytes to be encrypted in hex format:
        System.out.println("To be encrypted: " + bd.getEncoded("hex"));

        // To be encrypted: 000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F202122232425262728292A2B2C2D2E2F3031

        // RSA encrypt the contents of the bd, replacing the contents with the RSA encrypted data.
        rsa.encryptBd(bd, false);

        // Now it is encrypted.
        System.out.println("Encrypted size = " + bd.getNumBytes());
        System.out.println(bd.getEncoded("hex"));

        // Encrypted size = 256
        // 749ED9D0A8767C06C09AD9697F654F86B145F966722F9714902C4175BDBD02E68984ECF111D4D461
        // EDB4A8E677D399D19CCA60F35C6DE9972F4262880FE9D77DB75915393E8E7DB80AAB5E383013FAEB
        // 60C77D1E6FECC9A7C8426976416C6218FE7DA998EE063CE709E79C240F8625F4A56A0A33AFD63F7A
        // BA26F2A692B42E878C53B78602C725FE63FF961A46A2B9D436E5E3D9D64AE3F1D1F5AD5F5B47FCD69
        // 447306B77F2FD6D766CCAA1A110A3371586B43DF0D7FFE2220D1B305CF9371AC342F849FB0C90CD99E
        // C176928D877FE1C0DE1A7CB6EB824FEC7E1DCF90EF2C6BA9F1DFD3EBFBE89C51AF074DC6AE02E544A78
        // 5018C36D3D48B2EF5202AF61AC

        // ------------------------------------------------------------------------------------------------------------------------
        // Let's decrypt, which requires the matching private key...

        // Load the matching 2048-bit RSA private key.
        PrivateKey privKey = new PrivateKey();
        String password = "secret";
        try {
            privKey.loadAnyFormatFile("rsaKeys/myTestRsaPrivate.pem", password);

            // Tell the RSA object to use the private key.
            rsa.usePrivateKey(privKey);

            // Decrypt
            rsa.decryptBd(bd, true);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Examine the contents of bd to see if it now contains the unencrypted original data.
        System.out.println("Decrypted: " + bd.getEncoded("hex"));

        // Decrypted: 000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F202122232425262728292A2B2C2D2E2F3031
    }
}