The content of this is a simple class that decrypts characters:
Then call its encrypt or decrypt method with an authenticator byte array (the parameter Auth which is a 16 octet byte array) and the data which is wanted to be encoded or decoded, the result is a byte array you wanted.
Package org.kyle.util;
Import java.security. *;
Import java.io. *;
Import java.text. *;
Import java.util. *;
Import java.math. *;
/ * Call The Shared Secret S and The Pseudo-Random 128-bit
Authenticator Ra. Break The Password Into 16-OcTet Chunks P1, P2,
Etc. with the last one padded at the end with nulls to a 16-octet
Boundary. Call The Ciphertext Blocks C (1), C (2), etc. We'll NEED
Intermediate Values B1, B2, ETC.
B1 = MD5 (S RA) C (1) = p1 xor b1
B2 = MD5 (S C (1)) C (2) = p2 xor b2
.
.
.
Bi = MD5 (S C (I-1)) c (i) = pi xor bi
THE STRING WILL CONTAIN C (1) C (2) ... C (i) Where Denotes
Concatenation.
On Receipt, The Process Is Reverse To Yield The Original
Password.
* /
Public Class Cryptology
{
/ ** Hidden Secret Data for Encryption and Decryption. * /
Private Byte [] m_secret;
/ ** Default Secret Length. * /
Private int m_defaultsecretLength = 256;
/ **
* Default constructor to create Object with default Hidden Secret.
* /
Public Cryptology () PUBLIC CRYPTOLOGY ()
{
m_secret = CreateSecret (M_DefaultSecretLength, Normalize (). getName ()));
}
/ **
* Allow to use user desired Hidden Secret To Instantiate this Object.
* @Param Specsecret The User Desired Hidden Secret String.
* @Param Secretlen the length of secret in bytes.
* /
Public Cryptology (String Specsecret, int SECRETLEN)
{
IF (SpecSecret == Null) specsecret = getClass (). getname ();
m_secret = CREATESECRET (Secretlen, Normalize (SpecSecret);
}
/ **
* SET A New Shared Secret for Encryption and Decryption.
* @Param newsecret Byte [] The New Shared Secret.
* /
Public void setsecret (Byte [] newsecret
{
m_secret = newsecret;
}
/ **
* Set a string for shared secret.
* /
Public void setsecret (String Therecret)
{
m_secret = Normalize (THESECRET);
}
Public Byte [] getsecret ()
{
Return m_secret;
}
/ **
Encrypting the Rawdata with Random Auth value.
* /
Public Byte [] encrypt (byte [] rawdata, byte [] auth)
{
// if no secret or no automator data, don't Encrypt The Rawdata.
IF (Rawdata == Null ||
Auth == null ||
Auth.Length! = 16 ||
m_secret == NULL)
Return Rawdata;
ArrayList CBlocks = getCipherblocks (getchunks (Rawdata), AUTH, TRUE;
Return Concatchunks (CBLOCKS);
}
/ **
Decoding The Encoded Data (Encdata) with Given Authenticator Array (Auth). The result is the byte array of plain value.
* /
Public Byte [] Decrypt (byte [] encData, byte [] auth
{
// if no secret or no automator data, don't decrypt the Encdata.
IF (encData == null ||
Auth == null ||
Auth.Length! = 16 ||
m_secret == NULL)
Return ENCDATA;
ArrayList CBLOCKS = GetCipherblocks (Getchunks (EncData), Auth, False;
Return Concatchunks (CBLOCKS);
}
/ **
* Data to Be Encrypted Should Be Normalized to Multiple 16 OCTES FIRST.
* Origin String Should Be Encoded to Bytes in UTF-8. IF UTF-8 Not Supported, * Null Will Be Returned.
* /
Public static Byte [] Normalize (String WDATA)
{
Try
{
Byte Odata [] = WData.getbytes ("UTF-8"); // Return Bnormalize (ODATA);
Return Odata;
}
Catch (unsupportedencodingexception UEE)
{
//Debug.println (New DBGMSG (UEE, 3));
Debug.Warning ("Normalize Unsupportedencodingexception In Class Cryptology);
}
Return NULL;
}
/ **
* Get the utf-8 encoded string of a decrypted byte arch.
* @Param Odata Byte Array Which Was Decrypted from an encrypted byte Array.
* @Return String Encoded in UTF-8. if Odata Length is Zero,
* EMPTY STRING RETURNED, IF UTF-8 Not Supported, NULL RETURNED.
* /
Public static string rnormalize (byte odata [])
{
Int wdlen = odata.length;
//Debug.println ("raw data length: " wdlen);
IF (wdlen == 0) Return "";
Try
{
Return New String (OData, "UTF-8");
}
Catch (unsupportedencodingexception UEE)
{
Debug.Warning ("Normalize Unsupportedencodingexception In Class Cryptology);
}
Return NULL;
}
Private Byte [] Concatchunks (ArrayList Chunks)
{
IF (chunks == null) Return New Byte [0];
BYTEARRAYOUTPUTSTREAM baos = new byteArrayoutputStream ();
For (int i = 0; i { Biginteger bgint = (Biginteger) Chunks.get (i); Byte [] CBYTES = BGINT.TOBYTEARRAY (); Baos.Write (Cbytes, 0, CBYTES.LENGTH); } Return baos.tobytearray (); } // Private arraylist getcipherblocks (arraylist pchunks, byte [] rabytes, boolean cipher) { IF (m_secret == null || rabytes == null || pchunks == null) Return NULL; BYTE [] ss = new byte [m_secret.length]; System.ArrayCopy (m_secret, 0, s, 0, m_secret.length); Iterator IPS = PChunks.ITerator (); ArrayList Cipherblocks = New ArrayList (pchunks.size ()); Biginteger Bi = GetMedcialue (SS, RABYTES); String interface = "intermedium integer:" bi.intValue () "/ n"; String ciph = ""; While (ips.hasnext ()) { Biginteger Pi = (Biginteger) ips.next (); Biginteger Ci = Cipherblock (PI, BI); // Error Occurred, Invalid Password Not Necessary to be createdebug.println ("Intermediate Integer:" bi.intValue ()); ED. IF (CI == Null) Return NULL; Cipherblocks.Add (CI); // CIPH = "CREATED CIPHERED INTEGER:" CI.intValue () "(Bitlen:" Ci.bitLength () ") / n"; IF (cipher) Bi = getIntmedivalue (ss, ci.tobytearray ()); Else Bi = getIntmedivalue (ss, pi.tobytearay ()); // Inter = "Intermediate integer:" (bi == null? "null": bi.intValue () (Bitlen: " bi.bitLength ()") / n "); } //Debug.println (new dbgmsg (inter, debug.trace_in); //Debug.println (new dbgmsg (ciph, debug.trace_in); Return Cipherblocks; } Private arraylist getchunks (byte [] rawpwd) { IF (Rawpwd == Null) Return NULL; INT chunkcnt = (Rawpwd.Length 15) / 16; ArrayList Chunks = New ArrayList (chunkcnt); BYTEARRAYINPUTSTREAM Bais = New byteArrayInputStream (Rawpwd); String msg = ""; For (int i = 0; i { INT LEN = Bais.available (); IF (len> 16) len = 16; Byte [] chunk = new byte [16]; Int Bitlen = Bais.read (chunk, 0, len); //Debug.println ("AREAD BYTES:" Bitlen "; Value:" (New String (chunk)); IF (Bitlen! = -1) { IF (Len <16) Arrays.Fill (CHUNK, LEN, 15, (Byte) 0x00); Biginteger Bi = New Biginteger (Chunk); Chunks.Add (BI); } } //Debug.println (new dbgmsg (msg, debug.trace_in); Return chunks; } Private Biginteger getIntmediValue (byte [] second, byte [] raorct) { IF (Secret == null || raorct == null || raorct.Length <16) Return NULL; Try { MessageDigest Msgdgt = MessageDigest.getInstance ("MD5"); Byte [] INPUT = New Byte [Secret.length raorct.length]; System.ArrayCopy (Secret, 0, Input, 0, Secret.length); System.ArrayCopy (raorct, 0, input, secret.length, raorct.length); Return New Biginteger (Msgdgt.Digest (Input)); } Catch (NosuchalgorithMexception NSAE) { Debug.warning ("Normalize Nosuchalgorithmexception In Class Cryptology); } Return NULL; } Private Biginteger Cipherblock (Biginteger Pi, Biginteger Bi) { IF (pi == null || bi == null) Return NULL; Biginteger CPBK = pi.xor (bi); Return CPBK; } / ** * If a password's length is less 16, it will be padded * To 16 with null. This Makes ITS Decrypted Value Have A * Invalid Tail Encoded in the Nulls. This Method Will Compare * The string from decrypted bytes and stiled Origin String * with the palming nulls tail considered. * @Param DecryptedPwd The Restored Password String * Created from decrypted bytes. * @Param StoredPwd The Origin Password Stored * For authentication. * @Return Boolean True IF and Only if The DecryptedPWD * Is started with storedpwd and appended * BY a serias of nulls or none. * / Public Static Boolean Equals (String DecryptedPwd, String StoredPwd) { Try { IF (decryptedpwd.length () Byte [] DP = DecryptedPwd.getbytes ("ISO-8859-1"); Byte [] sp = storedpwd.getbytes ("ISO-8859-1"); IF (DP.LENGTH> Sp.Length) { INT tlen = dp.length - sp.Length; Byte [] SPE = New byte [TLEN]; Arrays.Fill (Spe, (Byte) 0x00); BYTEARRAYOUTPUTSTREAM baos = new byteArrayoutputStream (); Baos.Write (SP); Baos.Write (SPE); sp = baos.tobytearray (); } Return Arrays.Equals (DP, SP); } Catch (Exception E) { Debug.warning ("Normalize Exception In Class Cryptology); } Return False; } Private Byte [] CreateSecret (Int Len, Byte [] SEED { IF (SEED == NULL) { Seed = normalize (getClass (). getname ()); } IF (len <= 0) len = m_defaultsecretLength; Securerandom Scrdm = New Securerandom (SEED); BYTE [] ASEC = New byte [len]; SCRDM.NEXTBYTES (ASEC); Return ASEC; } / ** * If a password's length is less 16, it will be padded * To 16 with null. This Makes ITS Decrypted Value Have A * INVALID TAIL ENCODEDION THE NULLS. THIS Method Will Cut the * INVALID TAIL AND RETURN The "Clear" DATA. * @Param data byte [] The Origin Decrypted byte Array. * @Return Byte [] bytes from data without the nulls tail. * If any Exception Occurred, NULL RETURNED. * / Public static botty [] getcleardata (byte [] data) { Try { StringBuffer SB = new stringbuffer (); SB.Append (New String (Data, "ISO-8859-1)); sb.reverse (); Biginteger RBI = New Biginteger (sb.tostring (). GetBytes ("ISO-8859-1"); SB = New StringBuffer (); Sb.append (new string (rbi.tobytearray (), "ISO-8859-1")); sb.reverse (); Return sb.toString (). GetBytes ("ISO-8859-1"); } Catch (Exception E) { Debug.warning ("Normalize Exception In Class Cryptology); } Return NULL; } / * // for test Public static void main (String Argv []) { Cryptology Crypto = New Cryptology (); IF (argv.length <1) { System.exit (0); } // store default secret to file default.sec Try { FileOutputStream Fos = New FileoutputStream ("default.sec"); Fos.write (crypto.getSecret ()); Fos.close (); } Catch (IOException E) {} IF (argv.Length == 2) Crypto.setsecret (Argv [1]); Securerandom SCRDM = New Securerandom (Securerandom.getSeed (16)); Byte [] auth = new byte [16]; SCRDM.NEXTBYTES (Auth); String Rawstr = argv [0]; System.out.println ("Origin String:" RawStr); Byte [] scstr = crypto.normalize (rawstr); IF (scstr == null) { System.out.println ("Normalization of Origin String Failed."); System.exit (0); } Try { SCSTR = Crypto.encrypt (SCSTR, AUTH); System.out.println ("Encrypted String:" Crypto.rnormalize (SCSTR); bytescount: " scstr.length); SCSTR = Crypto.decrypt (SCSTR, AUTH); System.out.println ("Decrypted String:" Crypto.rnormalize (SCSTR)); System.out.println ("Cleared Decrypted Password:" (Cryptology.getCleardata)))))) } Catch (Exception UEE) {} } * / }
