AES encryption, aes

AES encryption, aes

Package com.edu. hpu;

 

Import java. math. BigInteger;

Import java. security. MessageDigest;

Import java. security. SecureRandom;

 

Import javax. crypto. Cipher;

Import javax. crypto. KeyGenerator;

Import javax. crypto. spec. SecretKeySpec;

 

Import sun. misc. BASE64Decoder;

Import sun. misc. BASE64Encoder;

 

Public class No14 {

Public static void main (String [] args) throws Exception {

String content = "***";

System. out. println ("before encryption:" + content );

String key = "123 ";

System. out. println ("encryption key and decryption key:" + (int) '1' + "" + (int) '2' + "" + (int) '3 ');

String encrypt = aesEncrypt (content, key );

System. out. println ("ciphertext:" + encrypt );

String decrypt = aesDecrypt (encrypt, key );

System. out. println ("decrypted:" + decrypt );

}

/**

* Convert byte [] to various hexadecimal strings.

* @ Param bytes byte []

* @ Param radix: converts the hexadecimal range from Character. MIN_RADIX to Character. MAX_RADIX. If the range is exceeded, it changes to 10 hexadecimal.

* @ Return refers to the converted string.

*/

Public static String binary (byte [] bytes, int radix ){

Return new BigInteger (1, bytes). toString (radix); // here 1 represents a positive number

}

/**

* Base 64 encode

* @ Param bytes byte to be encoded []

* @ Return encoded base 64 code

*/

Public static String base64Encode (byte [] bytes ){

Return new BASE64Encoder (). encode (bytes );

}

/**

* Base 64 decode

* @ Param base64Code base 64 code to be decoded

* @ Return the decoded byte []

* @ Throws Exception

*/

Public static byte [] base64Decode (String base64Code) throws Exception {

Return QStringUtil. isEmpty (base64Code )? Null: new BASE64Decoder (). decodeBuffer (base64Code );

}

/**

* Obtain the md5 value of byte []

* @ Param bytes byte []

* @ Return md5

* @ Throws Exception

*/

Public static byte [] md5 (byte [] bytes) throws Exception {

MessageDigest md = MessageDigest. getInstance ("MD5 ");

Md. update (bytes );

Return md. digest ();

}

/**

* Obtain the md5 value of a string.

* @ Param msg

* @ Return md5

* @ Throws Exception

*/

Public static byte [] md5 (String msg) throws Exception {

Return QStringUtil. isEmpty (msg )? Null: md5 (msg. getBytes ());

}

/**

* Implements md5 encryption with base64

* @ Param msg the string to be encrypted

* @ Return convert the md5 value to base64

* @ Throws Exception

*/

Public static String md5Encrypt (String msg) throws Exception {

Return QStringUtil. isEmpty (msg )? Null: base64Encode (md5 (msg ));

}

/**

* AES Encryption

* @ Param content to be encrypted

* @ Param encryptKey: encryption key

* @ Return encrypted byte []

* @ Throws Exception

*/

Public static byte [] aesEncryptToBytes (String content, String encryptKey) throws Exception {

// Encryption and decryption are added; otherwise, the encryption results of different machines are inconsistent.

KeyGenerator kgen = KeyGenerator. getInstance ("AES ");

SecureRandom random = SecureRandom. getInstance ("SHA1PRNG ");

Random. setSeed (encryptKey. getBytes ());

Kgen. init (128, random );

// General statement

// KeyGenerator kgen = KeyGenerator. getInstance ("AES ");

// Kgen. init (128, new SecureRandom (encryptKey. getBytes ()));

Cipher cipher = Cipher. getInstance ("AES ");

Cipher. init (Cipher. ENCRYPT_MODE, new SecretKeySpec (kgen. generateKey (). getEncoded (), "AES "));

Return cipher. doFinal (content. getBytes ("UTF-8 "));

}

/**

* AES encrypted to base 64 code

* @ Param content to be encrypted

* @ Param encryptKey: encryption key

* @ Return encrypted base 64 code

* @ Throws Exception

*/

Public static String aesEncrypt (String content, String encryptKey) throws Exception {

Return base64Encode (aesEncryptToBytes (content, encryptKey ));

}

/**

* AES decryption

* @ Param encryptBytes the byte to be decrypted []

* @ Param decryptKey decryption key

* @ Return refers to the decrypted String

* @ Throws Exception

*/

Public static String aesdecryptbytes (byte [] encryptBytes, String decryptKey) throws Exception {

// Encryption and decryption are added; otherwise, the encryption results of different machines are inconsistent.

KeyGenerator kgen = KeyGenerator. getInstance ("AES ");

SecureRandom random = SecureRandom. getInstance ("SHA1PRNG ");

Random. setSeed (decryptKey. getBytes ());

Kgen. init (128, random );

// General statement

// KeyGenerator kgen = KeyGenerator. getInstance ("AES ");

// Kgen. init (128, new SecureRandom (decryptKey. getBytes ()));

Cipher cipher = Cipher. getInstance ("AES ");

Cipher. init (Cipher. DECRYPT_MODE, new SecretKeySpec (kgen. generateKey (). getEncoded (), "AES "));

Byte [] decryptBytes = cipher. doFinal (encryptBytes );

Return new String (decryptBytes );

}

/**

* Decrypt base 64-code AES

* @ Param encryptStr base 64 code to be decrypted

* @ Param decryptKey decryption key

* @ Return refers to the decrypted string

* @ Throws Exception

*/

Public static String aesDecrypt (String encryptStr, String decryptKey) throws Exception {

Return QStringUtil. isEmpty (encryptStr )? Null: aesdecryptbytes (base64Decode (encryptStr), decryptKey );

}

}

 

Class QStringUtil {

Public static boolean isEmpty (String str ){

If (str = null ){

Return true;

} Else {

Return false;

}

 

}

}