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[] ivBytes = "12345123".getBytes();
SecretKeySpec key = new SecretKeySpec(keyBytes, "DES");
IvParameterSpec ivSpec = new IvParameterSpec(new byte[8]);
Cipher cipher = Cipher.getInstance("DES/CBC/PKCS7Padding", "BC");
cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec);
byte[] cipherText = new byte[cipher.getOutputSize(ivBytes.length + input.length)];
int ctLength = cipher.update(ivBytes, 0, ivBytes.length, cipherText, 0);
ctLength += cipher.update(input, 0, input.length, cipherText, ctLength);
ctLength += cipher.doFinal(cipherText, ctLength);
cipher.init(Cipher.DECRYPT_MODE, key, ivSpec);
byte[] buf = new byte[cipher.getOutputSize(ctLength)];
int bufLength = cipher.update(cipherText, 0, ctLength, buf, 0);
bufLength += cipher.doFinal(buf, bufLength);
byte[] plainText = new byte[bufLength - ivBytes.length];
System.arraycopy(buf, ivBytes.length, plainText, 0, plainText.length);
System.out.println("plain : " + new String(plainText));
}
}