AES Encryption Example

Recently used to encrypt the text content, and then looked at the usual encryption algorithm:

DES (Data Encryption Standard): symmetric algorithm, data encryption standards, fast, suitable for encrypting large amounts of data;
3DES (Triple des): is based on des symmetric algorithm, a piece of data with three different keys for three times encryption, higher intensity;
RC2 and RC4: symmetric algorithm, using variable-length key to encrypt large amounts of data, faster than DES;
IDEA (International Data encryption algorithm) International data encryption algorithm, using 128-bit key to provide very strong security;
RSA: Invented by RSA, is a public key algorithm that supports variable-length key, and the length of the file block that needs to be encrypted is also variable, asymmetric algorithm;
DSA (Digitally Signature algorithm): Digital Signature Algorithm, is a standard DSS (digital signature standard), strictly speaking, is not a cryptographic algorithm;
AES (Advanced encryption): High Encryption Standard, symmetric algorithm, is the next generation of cryptographic algorithm standard, fast, high security level, the current implementation of the AES standard is the Rijndael algorithm;
BLOWFISH, which uses a variable-length key, can be up to 448 bits long and runs fast;
MD5: Strictly speaking is not a cryptographic algorithm, can only be said to be a digest algorithm.

The following is an example of a Java implementation of AES plus decryption:

Encryption:

/*
* Encrypt
* @param content:
* @param Password:
*/
private static byte[] Encrypt (string content, string password) {
try {
Keygenerator KGen = keygenerator.getinstance ("AES");
Kgen.init (+, New SecureRandom (Password.getbytes ()));
Secretkey Secretkey = Kgen.generatekey ();
byte[] Encodeformat = secretkey.getencoded ();
Secretkeyspec key = new Secretkeyspec (Encodeformat, "AES");
Cipher Cipher = cipher.getinstance ("AES");
byte[] bytecontent = content.getbytes ("Utf-8");
Cipher.init (Cipher.encrypt_mode, key);
Byte[] result = cipher.dofinal (bytecontent);
return result;
} catch (NoSuchAlgorithmException e) {
E.printstacktrace ();
} catch (Nosuchpaddingexception e) {
E.printstacktrace ();
} catch (InvalidKeyException e) {
E.printstacktrace ();
} catch (Unsupportedencodingexception e) {
E.printstacktrace ();
} catch (Illegalblocksizeexception e) {
E.printstacktrace ();
} catch (Badpaddingexception e) {
E.printstacktrace ();
}

return null;
}

Decrypt:
/*
* Decrypt
* @param content:
* @param Password:
*/
private static byte[] Decrypt (byte[] content, String password) {
try {
Keygenerator KGen = keygenerator.getinstance ("AES");
Kgen.init (+, New SecureRandom (Password.getbytes ()));
Secretkey Secretkey = Kgen.generatekey ();
byte[] Encodeformat = secretkey.getencoded ();
Secretkeyspec key = new Secretkeyspec (Encodeformat, "AES");
Cipher Cipher = cipher.getinstance ("AES");
Cipher.init (Cipher.decrypt_mode, key);
Byte[] result = cipher.dofinal (content);
return result;
} catch (NoSuchAlgorithmException e) {
E.printstacktrace ();
} catch (Nosuchpaddingexception e) {
E.printstacktrace ();
} catch (InvalidKeyException e) {
E.printstacktrace ();
} catch (Illegalblocksizeexception e) {
E.printstacktrace ();
} catch (Badpaddingexception e) {
E.printstacktrace ();
}

return null;
}

Example:

String content = "Test";
String password = "12345678";
Encryption
System.out.println ("Before encryption:" + content);
byte[] Encryptresult = Encrypt (content, password);
Decrypt
byte[] Decryptresult = Decrypt (Encryptresult,password);
System.out.println ("decrypted:" + new String (Decryptresult));

If you want the hexadecimal display after encryption, you can add two functions, binary and 16 binary conversions
Binary conversion to 16 binary:

private static String Parsebyte2hexstr (byte buf[]) {
StringBuffer sb = new StringBuffer ();
for (int i = 0; i < buf.length; i++) {
String hex = integer.tohexstring (Buf[i] & 0xFF);
if (hex.length () = = 1) {
Hex = ' 0 ' + hex;
}
Sb.append (Hex.touppercase ());
}
return sb.tostring ();
}

16 binary conversion to binary:
private static byte[] Parsehexstr2byte (String hexstr) {
if (Hexstr.length () < 1) {
return null;
}

Byte[] result = new Byte[hexstr.length ()/2];
for (int i = 0; i < hexstr.length ()/2; i++) {
int high = Integer.parseint (Hexstr.substring (i*2, i*2+1), 16);
int low = Integer.parseint (Hexstr.substring (i*2+1, i*2+2), 16);
Result[i] = (byte) (high * + low);
}
return result;
}

Example:

String content = "Test";
String password = "12345678";
Encryption
System.out.println ("Before encryption:" + content);
byte[] Encryptresult = Encrypt (content, password);
String encryptresultstr = Parsebyte2hexstr (Encryptresult);
SYSTEM.OUT.PRINTLN ("After encryption:" + ENCRYPTRESULTSTR);
Decrypt
byte[] Decryptfrom = Parsehexstr2byte (ENCRYPTRESULTSTR);
byte[] Decryptresult = Decrypt (Decryptfrom,password);
System.out.println ("decrypted:" + new String (Decryptresult));

AES Encryption Example