1个块(16字节)的Java AES-128加密返回2个块(32字节)作为输出

Java AES-128 encryption of 1 block (16 byte) returns 2 blocks(32 byte) as output

我使用以下代码进行AES-128加密，以编码16字节的单个块，但编码值的长度为2个32字节的块。我错过了什么吗？

1	plainEnc = AES.encrypt("thisisapassword!");

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import java.security.*;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.*;
import sun.misc.*;

public class AES {

private static final String ALGO ="AES";
private static final byte[] keyValue =
new byte[] { 'T', 'h', 'e', 'B', 'e', 's', 't',
'S', 'e', 'c', 'r','e', 't', 'K', 'e', 'y' };

public static String encrypt(String Data) throws Exception {
System.out.println("string length:" + (Data.getBytes()).length); //length = 16
Key key = generateKey();
Cipher chiper = Cipher.getInstance(ALGO);
chiper.init(Cipher.ENCRYPT_MODE, key);
byte[] encVal = chiper.doFinal(Data.getBytes());
System.out.println("output length:" + encVal.length); //length = 32
String encryptedValue = new BASE64Encoder().encode(encVal);
return encryptedValue;
}

public static String decrypt(String encryptedData) throws Exception {
Key key = generateKey();
Cipher chiper = Cipher.getInstance(ALGO);
chiper.init(Cipher.DECRYPT_MODE, key);
byte[] decordedValue = new BASE64Decoder().decodeBuffer(encryptedData);
byte[] decValue = chiper.doFinal(decordedValue);
String decryptedValue = new String(decValue);
return decryptedValue;
}
private static Key generateKey() throws Exception {
Key key = new SecretKeySpec(keyValue, ALGO);
return key;
}

}

相关讨论

Cipher.getInstance("AES")返回使用PKCS＃5填充的密码。在所有情况下都添加了此填充 - 当明文已经是块大小的倍数时，将添加整个填充块。

在Cipher.getInstance()调用中明确指定您的意图，以避免依赖于默认值并可能导致混淆：

1	Cipher.getInstance("AES/ECB/NoPadding");

您还将看到您正在使用ECB模式，这在几乎任何情况下都是一个糟糕的选择。