MainClass.java Source code

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Here is the source code for MainClass.java

Source

import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class MainClass {
    public static void main(String[] args) throws Exception {
        Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

        byte[] input = "input".getBytes();
        byte[] keyBytes = "input123".getBytes();
        byte[] msgNumber = "input".getBytes();

        IvParameterSpec zeroIv = new IvParameterSpec(new byte[8]);

        SecretKeySpec key = new SecretKeySpec(keyBytes, "DES");

        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS7Padding", "BC");

        cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);

        IvParameterSpec encryptionIv = new IvParameterSpec(cipher.doFinal(msgNumber), 0, 8);

        cipher.init(Cipher.ENCRYPT_MODE, key, encryptionIv);

        byte[] cipherText = new byte[cipher.getOutputSize(input.length)];

        int ctLength = cipher.update(input, 0, input.length, cipherText, 0);

        ctLength += cipher.doFinal(cipherText, ctLength);

        System.out.println("cipher: " + new String(cipherText) + " bytes: " + ctLength);
        cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);

        IvParameterSpec decryptionIv = new IvParameterSpec(cipher.doFinal(msgNumber), 0, 8);

        cipher.init(Cipher.DECRYPT_MODE, key, decryptionIv);

        byte[] plainText = new byte[cipher.getOutputSize(ctLength)];

        int ptLength = cipher.update(cipherText, 0, ctLength, plainText, 0);

        ptLength += cipher.doFinal(plainText, ptLength);

        System.out.println("plain : " + new String(plainText, ptLength));
    }
}