Java: AES encryption using CTR mode; Unable to decrypt
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Java
I'm using the following code, but it doesn't decrypt the text correctly. What I get is output
Encryption:% no2f? ¢¶SHºûÅ“? ¾
Plaintext: Hello × amoriginÎl
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
// Dernier exemple CTR mode
// Clé 16 bits
byte[] keyBytes = new byte[] { (byte) 0x36,(byte) 0xf1,(byte) 0x83,(byte) 0x57,(byte) 0xbe,(byte) 0x4d,(byte) 0xbd,(byte) 0x77,(byte) 0xf0,(byte) 0x50,(byte) 0x51,(byte) 0x5c,0x73,(byte) 0xfc,(byte) 0xf9,(byte) 0xf2 };
// IV 16 bits (préfixe du cipherText)
byte[] ivBytes = new byte[] { (byte) 0x69,(byte) 0xdd,(byte) 0xa8,(byte) 0x45,(byte) 0x7d,(byte) 0xd4,(byte) 0x25,(byte) 0x4b,(byte) 0xf3,(byte) 0x53,(byte) 0xb7,(byte) 0x73,(byte) 0x30,(byte) 0x4e,(byte) 0xec };
// Initialisation
SecretKeySpec key = new SecretKeySpec(keyBytes,"AES");
IvParameterSpec ivSpec = new IvParameterSpec(ivBytes);
// Mode
Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding");
String originalText = "hello i am original";
// ///////////////////////////////ENCRYPTING
cipher.init(Cipher.ENCRYPT_MODE,key,ivSpec);
byte[] ciphered = cipher.doFinal(originalText.getBytes());
String cipherText = new String(ciphered,"UTF-8");
System.out.println("ciphered: " + cipherText);
// ///////////////////////////////DECRYPTING
cipher = Cipher.getInstance("AES/CTR/NoPadding");
cipher.**init(Cipher.DECRYPT_MODE**,ivSpec);
byte[] plain = **cipher.doFinal(ciphered);**
originalText = new String(plain,"UTF-8");
System.out.println("plaintext: " + originalText);
}
I can't figure out what I did wrong Thank you very much for any help This is also the correct way to encrypt some data. This time I tried to encrypt the 4byte City password thanks in advance
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I made those changes and it worked well, but if I passed, the problem is what cipher Ciphertext. In init() function getByte(). like
byte[] plain = cipher.doFinal(cipherText.getByte("UTF-8"));
'Thank you for your help
Solution
For decryption, you need to be in decrypt_ Initialization password in mode And the conversion from byte [] to string is incorrect (see other answers)
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