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import java.security.Key;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.Security;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
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());
SecureRandom random = new SecureRandom();
IvParameterSpec ivSpec = createCtrIvForAES();
Key key = createKeyForAES(256, random);
Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding", "BC");
String input = "12345678";
Mac hMac = Mac.getInstance("HmacSHA1", "BC");
Key hMacKey = new SecretKeySpec(key.getEncoded(), "HmacSHA1");
System.out.println("input : " + input);
cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec);
byte[] cipherText = new byte[cipher.getOutputSize(input.length() + hMac.getMacLength())];
int ctLength = cipher.update(input.getBytes(), 0, input.length(), cipherText, 0);
hMac.init(hMacKey);
hMac.update(input.getBytes());
ctLength += cipher.doFinal(hMac.doFinal(), 0, hMac.getMacLength(), cipherText, ctLength);
cipherText[9] ^= '0' ^ '9';
cipher.init(Cipher.DECRYPT_MODE, key, ivSpec);
byte[] plainText = cipher.doFinal(cipherText, 0, ctLength);
int messageLength = plainText.length - hMac.getMacLength();
hMac.init(hMacKey);
hMac.update(plainText, 0, messageLength);
byte[] messageHash = new byte[hMac.getMacLength()];
System.arraycopy(plainText, messageLength, messageHash, 0, messageHash.length);
System.out.println("plain : " + new String(plainText) + " verified: "
+ MessageDigest.isEqual(hMac.doFinal(), messageHash));
}
public static SecretKey createKeyForAES(int bitLength, SecureRandom random)
throws NoSuchAlgorithmException, NoSuchProviderException {
KeyGenerator generator = KeyGenerator.getInstance("AES", "BC");
generator.init(128, random);
return generator.generateKey();
}
public static IvParameterSpec createCtrIvForAES() {
return new IvParameterSpec("1234567812345678".getBytes());
}
}
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