C # reversible and irreversible MD5 Encryption

1. method 1 (irreversible encryption) srxljl

Public String encryptpassword (string passwordstring, string passwordformat)
{
String encryptpassword = NULL;
If (passwordformat = "sha1 "){
Encryptpassword = formsauthortication. hashpasswordforstoringinconfigfile (passwordstring, "sha1 ");
}
Elseif (passwordformat = "MD5 ")
{

Encryptpassword = formsauthortication. hashpasswordforstoringinconfigfile (passwordstring, "MD5 ");
}
Return encryptpassword;
}

 

2. method 2 (reversible encryption) srxljl

 

Public interface ibindesh
{
String encode (string Str );
String decode (string Str );
}

Public class encryptiondecryption: ibindesh
{
Public String encode (string Str)
{
String htext = "";

For (INT I = 0; I <Str. length; I ++)
{
Htext = htext + (char) (STR [I] + 10-1*2 );
}
Return htext;
}

Public String decode (string Str)
{
String dtext = "";

For (INT I = 0; I <Str. length; I ++)
{
Dtext = dtext + (char) (STR [I]-10 + 1*2 );
}
Return dtext;
}

 

3. Method 3 (reversible encryption) srxljl

 

Const string key_64 = "vavicapp"; // note that it is 8 characters long and 64-bit

Const string iv_64 = "vavicapp ";
Public String encode (string data)
{
Byte [] bykey = system. Text. asciiencoding. ASCII. getbytes (key_64 );
Byte [] byiv = system. Text. asciiencoding. ASCII. getbytes (iv_64 );

Descryptoserviceprovider cryptoprovider = new descryptoserviceprovider ();
Int I = cryptoprovider. keysize;
Memorystream MS = new memorystream ();
Cryptostream CST = new cryptostream (MS, cryptoprovider. createencryptor (bykey, byiv), cryptostreammode. Write );

Streamwriter Sw = new streamwriter (Cst );
Sw. Write (data );
Sw. Flush ();
CST. flushfinalblock ();
Sw. Flush ();
Return convert. tobase64string (Ms. getbuffer (), 0, (INT) ms. Length );

}

Public String decode (string data)
{
Byte [] bykey = system. Text. asciiencoding. ASCII. getbytes (key_64 );
Byte [] byiv = system. Text. asciiencoding. ASCII. getbytes (iv_64 );

Byte [] byenc;
Try
{
Byenc = convert. frombase64string (data );
}
Catch
{
Return NULL;
}

Descryptoserviceprovider cryptoprovider = new descryptoserviceprovider ();
Memorystream MS = new memorystream (byenc );
Cryptostream CST = new cryptostream (MS, cryptoprovider. createdecryptor (bykey, byiv), cryptostreammode. Read );
Streamreader sr = new streamreader (Cst );
Return Sr. readtoend ();
}

 

4. MD5 (32-bit encryption) srxljl

Public String getmd5 (string S, string _ input_charset)
{

/// <Summary>
/// ASP-compatible MD5 Encryption Algorithm
/// </Summary>

MD5 MD5 = new md5cryptoserviceprovider ();
Byte [] T = md5.computehash (encoding. getencoding (_ input_charset). getbytes (s ));
Stringbuilder sb = new stringbuilder (32 );
For (INT I = 0; I <t. length; I ++)
{
SB. append (T [I]. tostring ("X"). padleft (2, '0 '));
}
Return sb. tostring ();
}

(16-bit encryption) srxljl

 

Public static string getmd5str (string convertstring)
{
Md5cryptoserviceprovider MD5 = new md5cryptoserviceprovider ();
String t2 = bitconverter. tostring (md5.computehash (utf8encoding. Default. getbytes (convertstring), 4, 8 );
T2 = t2.replace ("-","");
Return T2;
}

 

5. Add and unbind the text file srxljl

 

// Encrypt the file
Private Static void encryptdata (string inname, string outname, byte [] cipher ey, byte [] desiv)
{
// Create the file streams to handle the input and output files.
Filestream fin = new filestream (inname, filemode. Open, fileaccess. Read );
Filestream fout = new filestream (outname, filemode. openorcreate, fileaccess. Write );
Fout. setlength (0 );

// Create variables to help with read and write.
Byte [] bin = new byte [100]; // This is intermediate storage for the encryption.
Long rdlen = 0; // This is the total number of bytes written.
Long totlen = fin. length; // This is the total length of the input file.
Int Len; // This is the number of bytes to be written at a time.

Des = new descryptoserviceprovider ();
Cryptostream encstream = new cryptostream (fout, Des. createencryptor (Cipher ey, desiv), cryptostreammode. Write );

// Read from the input file, then encrypt and write to the output file.
While (rdlen <totlen)
{
Len = fin. Read (bin, 0,100 );
Encstream. Write (bin, 0, Len );
Rdlen = rdlen + Len;
}

Encstream. Close ();
Fout. Close ();
Fin. Close ();
}

// Decrypt the file
Private Static void decryptdata (string inname, string outname, byte [] cipher ey, byte [] desiv)
{
// Create the file streams to handle the input and output files.
Filestream fin = new filestream (inname, filemode. Open, fileaccess. Read );
Filestream fout = new filestream (outname, filemode. openorcreate, fileaccess. Write );
Fout. setlength (0 );

// Create variables to help with read and write.
Byte [] bin = new byte [100]; // This is intermediate storage for the encryption.
Long rdlen = 0; // This is the total number of bytes written.
Long totlen = fin. length; // This is the total length of the input file.
Int Len; // This is the number of bytes to be written at a time.

Des = new descryptoserviceprovider ();
Cryptostream encstream = new cryptostream (fout, Des. createdecryptor (Cipher ey, desiv), cryptostreammode. Write );

// Read from the input file, then encrypt and write to the output file.
While (rdlen <totlen)
{
Len = fin. Read (bin, 0,100 );
Encstream. Write (bin, 0, Len );
Rdlen = rdlen + Len;
}

Encstream. Close ();
Fout. Close ();
Fin. Close ();
}