Packaging test;
Import java.io.fileinputstream;
Import java.io.fileoutputstream;
Import java.io.ioexception;
Import java.io.objectinputstream;
Import java.io.objectoutputstream;
Import java.security. *;
Import javax.crypto.cipher;
Import javax.crypto.keygenerator;
Import javax.crypto.secret key;
/**
* Encryption and decryption
*
* @ author shy.qiu
* @ from/qiushuyfm
*/
Public class password test {
/**
* MD5 encryption.
*
* @param info
* Information to be encrypted
* @ Returns a string encrypted string.
*/
Public string encryptToMD5 (string information) (
byte[]digesta = null；
Try {
//Get the message summary of md5.
message digest alga = message digest . getinstance(" MD5 ")；
//Add information to summarize.
alga . update(info . getbytes())；
//Get the summary
digesta = alga . digest()；
} catch(nosuch algorithm exception e){
e . printstacktrace()；
}
//Convert the summary into a string
string RS = byte 2 hex(digesta)；
Return RS;
}
/**
* SHA encryption.
*
* @param info
* Information to be encrypted
* @ Returns a string encrypted string.
*/
Public string encryptToSHA (string information)
byte[]digesta = null；
Try {
//Get the message digest of SHA- 1
message digest alga = message digest . getinstance(" SHA- 1 ")；
//Add information to summarize.
alga . update(info . getbytes())；
//Get the summary
digesta = alga . digest()；
} catch(nosuch algorithm exception e){
e . printstacktrace()；
}
//Convert the summary into a string
string RS = byte 2 hex(digesta)；
Return RS;
}
// //////////////////////////////////////////////////////////////////////////
/**
* create a key
*
* @param algorithm
* encryption algorithm, available DES, DESede, Blowfish.
* @return SecretKey secret (symmetric) key
*/
Public SecretKey keyCreate a SecretKey (string algorithm) (
//Declare the KeyGenerator object
KeyGenerator keygen
//Declare the key object
SecretKey deskey = null
Try {
//Returns the KeyGenerator object that generates the key for the specified algorithm.
Keygen = keygenerator.getinstance (algorithm);
//Generate a key
deskey = keygen . generate key()；
} catch(nosuch algorithm exception e){
e . printstacktrace()；
}
//Return the key
Return to deskey
}
/**
* DES encryption according to the key.
*
* @param key
* key
* @param info
* Information to be encrypted
* @ returns string encryption information.
*/
Public string encrypto des(secret key, string information) (
//Define the encryption algorithm, which can be DES, DES, DESede, Blowfish.
String Algorithm = " DES
//Encrypted Random Number Generator (RNG), (no need to write)
SecureRandom Sr = new SecureRandom()；
//Define the ciphertext to be generated.
Byte [] Password Byte = empty;
Try {
//Get the encryption/decryption program
Cipher c1= cipher.getinstance (algorithm);
//Initializes the Cipher object with the specified key and mode.
//Parameters: (encrypt _ mode, decrypt _ mode, wrap _ mode, unwrap _ mode)
C 1.init (password. ENCRYPT_MODE，key，Sr)；
//encode the content to be encrypted,
cipher byte = c 1 . do final(info . getbytes())；
Catch (exception e) {
e . printstacktrace()；
}
//Returns the ciphertext in hexadecimal form.
Returns byte2hex (password byte);
}
/**
* DES decrypts according to the key.
*
* @param key
* key
* @param sInfo
* the ciphertext to be decrypted
* @return String returns the decrypted information.
*/
Common string decryptByDES(SecretKey key, string sinfo) (
//Define the encryption algorithm,
String Algorithm = " DES
//Encrypted Random Number Generator (RNG)
SecureRandom Sr = new SecureRandom()；
Byte [] Password Byte = empty;
Try {
//Get the encryption/decryption program
Cipher c1= cipher.getinstance (algorithm);
//Initializes the Cipher object with the specified key and mode.
C 1.init (password. DECRYPT_MODE，key，Sr)；
//Encode the content to be decrypted.
cipher byte = c 1 . do final(hex 2 byte(sInfo))；
Catch (exception e) {
e . printstacktrace()；
}
//Returns byte2hex (password byte);
Returns a new string (cipher byte);
}
// /////////////////////////////////////////////////////////////////////////////
/**
* Create a key group and put the public key and private key into the specified file.
*
* default in mykeys.bat file.
*/
public void createPairKey() {
Try {
//A key pair generator according to a specific algorithm.
KeyPairGenerator keygen = KeyPairGenerator . getinstance(" DSA ")；
//Encrypted Random Number Generator (RNG)
SecureRandom random = new SecureRandom()；
//Re-seed this random object.
random . setseed( 1000)；
//Initializes the key pair generator to determine the key size using the given random source (and default parameter set).
Keygen.initialize(5 12, random); //keygen . initialize(5 12)；
//Generate a key group
key pair keys = keygen . generatekeypair()；
//Get the public key
public key pubkey = keys . getpublic()；
//Get the private key
private key prikey = keys . get private()；
//Write the public key and private key into the document.
doObjToFile("mykeys.bat "，new Object[] { prikey，pubkey })；
} catch(nosuch algorithm exception e){
e . printstacktrace()；
}
}
/**
* use the private key to sign the information, and put the signed information into the specified file.
*
* @param info
* Information that needs to be signed
* @param signal file
* Deposited documents
*/
public void sign to info(String info，String signfile) {
//Read the private key from the file
private key my prikey =(private key)getObjFromFile(" mykeys . bat "， 1)；
//Read the public key from the file
public key my pubkey =(public key)getObjFromFile(" mykeys . bat "，2)；
Try {
The signature object can be used to generate and verify digital signatures.
signature signet = signature . getinstance(" DSA ")；
//Initialize the private key used to sign the signature.
signet . init sign(my prikey)；
//Update the data to be signed or verified by bytes.
signet . update(info . getbytes())；
//Sign or verify the signatures of all update bytes and return the signatures.
byte[]signed = signet . sign()；
//Put the digital signature, public key and information into the file.
doObjToFile(signfile，new Object[] { signed，mypubkey，info })；
Catch (exception e) {
e . printstacktrace()；
}
}
/**
* Read the digital signature file and verify the legality of the information according to the public key, signature and information.
*
* @ Returns true verification success and false verification failure.
*/
Public boolean validateSign (string signature file) (
//Read the public key
public key my pubkey =(public key)getObjFromFile(sign file，2)；
//Read the signature
byte[]signed =(byte[])getObjFromFile(sign file， 1)；
//Read information
String info =(String)getObjFromFile(sign file，3)；
Try {
//Initialize the signature object and verify it with the public key and signature.
signature signetcheck = signature . getinstance(" DSA ")；
//Initializes the public key of the verification signature.
signetcheck . init verify(my pubkey)；
//Update the data to be signed or verified with the specified byte array.
signetcheck . update(info . getbytes())；
system . out . println(info)；
//Verify the incoming signature
Returns signetcheck.verify (signed);
Catch (exception e) {
e . printstacktrace()；
Returns false
}
}
/**
* Convert binary to 16 binary string.
*
* @param b
* Binary byte array
* @ Returns a string
*/
Common string byte2hex(byte[] b) {
String hs =
String stmp =
for(int n = 0； N<b. length; n++) {
stmp =(Java . lang . integer . tohexstring(b[n]& amp； 0x ff))；
if (stmp.length() == 1) {
hs = hs+" 0 "+stmp；
} Otherwise {
hs = hs+stmp；
}
}
Returns hs.touppercase ();
}
/**
* Hexadecimal string is converted into binary.
*
* @param hex
* @ Return
*/
Public byte[] hex2byte (string hexadecimal) {
Byte[] ret = new byte [8];
byte[]tmp = hex . getbytes()；
for(int I = 0； I<8; i++) {
ret[i] = uniteBytes(tmp[i * 2]，tmp[I * 2+ 1])；
}
Return to ret
}
/**
* combine two ASCII characters into one byte; Such as "ef"-> 0xef
*
* @param src0
* bytes
* @param src 1
* bytes
* @ returns bytes
*/
Common static byte unit byte (byte src0, byte src 1) {
byte _ B0 = byte . decode(" 0x "+new String(new byte[]{ src 0 }))
. byte value()；
_b0 = (bytes) (_ B0 < < lt4);
byte _ b 1 = byte . decode(" 0x "+new String(new byte[]{ src 1 }))
. byte value()；
byte ret =(byte)(_ B0 ^ _ b 1)；
Return to ret
}
/**
* Write the specified object to the specified file.
*
* @param file
* Specify the file to write.
* @param objs
* The object to be written.
*/
Public void doObjToFile (string file, Object[] objs) {
ObjectOutputStream oos = null
Try {
file output stream fos = new file output stream(file)；
Oos = new object output stream (fos);
for(int I = 0； I & ltobjs.lengthi++) {
OOS . writeobject(objs[I])；
}
Catch (exception e) {
e . printstacktrace()；
} Finally {
Try {
OOS . close()；
} catch (IOException e) {
e . printstacktrace()；
}
}
}
/**
* Returns the object at the specified location in the file.
*
* @param file
* Specify the file
* @param i
* Starting from 1
* @ Return
*/
Common object getObjFromFile(String file, int i) {
ObjectInputStream ois = null
Object obj = null
Try {
file inputstream fis = new file inputstream(file)；
Ois = new objectinputstream (fis);
for(int j = 0； J< me; j++) {
obj = ois . read object()；
}
Catch (exception e) {
e . printstacktrace()；
} Finally {
Try {
ois . close()；
} catch (IOException e) {
e . printstacktrace()；
}
}
Return to obj
}
/**
* testing
*
* @param args
*/
Public static void main(String[] args) {
CryptTest jiami = new CryptTest()；
//Execute MD5 encryption "Hello world!"
System.out.println("Hello across MD5: "+jiami.encryptomd5 ("hello "));
//Generate a key of DES algorithm.
secret key key = jiami . create SecretKey(" DES ")；
//Encrypt the message "Hello world!" Use the key.
string str 1 = jiami . encrypto des(key，“Hello”)；
System.out.println ("Encrypt information hello is with des"+str1);
//Decrypt with this key.
string str 2 = jiami . decryptbydes(key，str 1)；
System.out.println ("after decryption:"+str 2);
//Create a public key and a private key.
jiami . createpairkey()；
//Yes, hello world! Sign with a private key
jiami.signToInfo("Hello "，" my sign . bat ")；
//Verify the signature with the public key.
if(jiami . validate sign(" my sign . bat "){
System.out.println ("Success!" );
} Otherwise {
System.out.println("Fail！" );
}
}
}