Android quickly understands password-based encryption (1) and android

Android quickly understands password-based encryption (1) and android

Import java. util. Random;

Import javax. crypto. Cipher;
Import javax. crypto. SecretKey;
Import javax. crypto. SecretKeyFactory;
Import javax. crypto. spec. PBEKeySpec;
Import javax. crypto. spec. PBEParameterSpec;

Public class Token {

/*
* Password-based encryption creation procedure
* 1. Read the password
* Convert the encrypted string to a character array
* Save the password to the PBEKeySpec object.
* 2. The key is generated by the password.
* Obtain the SecretKeyfactory object through the getInstance static method of the SecretKeyFactory class;
* The getInstance method requires a parameter -- specify the password encryption algorithm {
* 1. PBEWithMD5AndDES
* 2. PBEWithHmacSHA1AndDESede}
* Use the generateSecret () method of the SecretKeyFactory factory class to generate a secret key
* 3. Generate a random number (SALT)
* The salt must be a byte array of 8 elements.
* Use the nextbyte method of the Random class to generate a Random number and assign the Random number to the byte array. The parameter is a byte array.
* 4. Create and initialize a secret
* The getInstance method is used to obtain the secret object. The parameter is a password-based encryption algorithm.
* Use the PBEParameterSpec class constructor to specify password-based encryption algorithms (including salt that increases the difficulty of cracking) for the Cipher object)
* 5. Obtain and encrypt the plaintext.
* The encrypted doFinal () method is executed to encrypt the data. The encrypted results are stored in the byte array ctext.
**/
// Password encryption Operation Method
Public byte [] cmdEncryptionOperation (String encryptionStr, String pwdStr) throws Exception
{
// Read the password
// Convert the password into a character array
Char [] pwd = pwdStr. toCharArray ();
// Store the encrypted array to the PBEKeySpec object
PBEKeySpec pbeKeySpec = new PBEKeySpec (pwd );

// Generate a key using the password
// Create a SecretKeyFactory object using the getinstance method of SecretKeyFactory. The construction parameter is of the encryption type.
SecretKeyFactory secretKeyFactory = SecretKeyFactory
. GetInstance ("PBEWithMD5AndDES"); // throw a keyword error.
// GenerateSecret to generate a password
SecretKey key = secretKeyFactory. generateSecret (pbeKeySpec );

// Generate random number (SALT)
// Create the salt of the byte array with 8 Elements
Byte [] salt = new byte [8];
// Use the nextbyte method of the Random class to generate a Random number and assign the Random number to the byte array. The parameter is a byte array.
Random random = new Random ();
Random. nextBytes (salt );

// Create and initialize the secret
Cipher cipher = Cipher. getInstance ("PBEWithMD5AndDES ");
PBEParameterSpec parameterSpec = new PBEParameterSpec (salt, 1000 );
Cipher. init (Cipher. ENCRYPT_MODE, key, parameterSpec );

// Obtain the plaintext and encrypt it.
Byte [] ptext = encryptionStr. getBytes ("UTF-8 ");
Byte [] ctext = cipher. doFinal (ptext); // The dofinal method of cipher for encryption
Return ctext;
}

}

 

Encryption Method:

 

Public static void main (String [] args) throws Exception {
Token token = new Token ();
Byte [] ctext = token. cmdEncryptionOperation ("add QQ Group 499092562 !! "," 2016/4/5 ");
FileOutputStream OS = new FileOutputStream ("PBEEnc. dat ");
OS. write (ctext );
For (int I = 0; I <ctext. length; I ++ ){
System. out. print (ctext [I]);
}

}