Encryption, password unauthentication, Signature Verification

 

Using System;
Using System. Data;
Using System. configuration;
Using System. Web;
Using System. Web. Security;
Using System. Web. UI;
Using System. Web. UI. webcontrols;
Using System. Web. UI. webcontrols. webparts;
Using System. Web. UI. htmlcontrols;
Using System. Security;
Using System. Security. cryptography;
Using System. text;
Namespace Cryption
{
Public   Class Cryption
{

# RegionDifferences between convert. tobase64string and encoding. getstring
/*
*
Both convert byte [] to a string. The difference is that convert. tobase64string uses Base 64 numeric encoding, so it generates all ASCII characters.

However, encoding. getstring is a string that we generally know.

Some encryption methods return byte []. Which one should we use to convert the data to a string?

Using encoding. getstring conversion, you may get many squares or question marks. This is because some integer sequences cannot correspond to the text in our real life. They can only be replaced by squares or question marks.

Therefore, we generally use convert. tobase64string.

On the other hand, which one can be used to convert a string to a byte? Must I use frombase64string?

No. Our common text (such as string type) is not base64-encoded and cannot be converted to byte [] Using frombase64string, for example: frombase64string ("Qianyi network ") an error occurs, because the "Qianyi network" is not base64-encoded. In this case, encoding should be used. getbytes ().

*/

# Endregion

///   <Summary>
/// Obtain the public key and private key.
///   </Summary>
///   <Param name = "publickey"> </param>
///   <Param name = "privatekey"> </param>
Public   Static   Void Getkey ( Out   String Publickey, Out   String Privatekey)
{
Rsacryptoserviceprovider rsaprovider =   New Rsacryptoserviceprovider ();
Publickey = Rsaprovider. toxmlstring ( False );
Privatekey = Rsaprovider. toxmlstring ( True );
}

///   <Summary>
/// Add Password
///   </Summary>
///   <Param name = "publickey"> </param>
///   <Param name = "encrypttext"> </param>
///   <Returns> </returns>
Public   Static   String Encrypt ( String Publickey, String Encrypttext)
{

Byte [] Byteencrypttext =   New Unicodeencoding (). getbytes (encrypttext );
Rsacryptoserviceprovider rsprovider =   New Rsacryptoserviceprovider ();
Rsprovider. fromxmlstring (publickey );
Return Convert. tobase64string (rsprovider. Encrypt (byteencrypttext, False ));

}

///   <Summary>
/// Decryption
///   </Summary>
///   <Param name = "privatekey"> </param>
///   <Param name = "decrypttext"> </param>
///   <Returns> </returns>
Public   Static   String Decrypt ( String Privatekey, String Decrypttext)
{
Unicodeencoding uni =   New Unicodeencoding ();
Byte [] Byteencrypttext = Convert. frombase64string (decrypttext );
Rsacryptoserviceprovider rsprovider =   New Rsacryptoserviceprovider ();
Rsprovider. fromxmlstring (privatekey );
Return Uni. getstring (rsprovider. decrypt (byteencrypttext, False ));

}

///   <Summary>
/// Calculate the hash value of a specified byte array
///   </Summary>
///   <Param name = "text"> </param>
///   <Returns> </returns>
Public   Static   String Gethash ( String Text)
{
Byte [] Bytetext =   New Unicodeencoding (). getbytes (text );
Hashalgorithm ha = Hashalgorithm. Create ( " MD5 " );
Return Convert. tobase64string (Ha. computehash (bytetext ));
}

///   <Summary>
/// Create a signature
///   </Summary>
///   <Param name = "publickey"> </param>
///   <Param name = "text"> </param>
///   <Param name = "signaturetext"> Signed Data </Param>
///   <Returns> </returns>
Public   Static   Void Signatureformatter ( String Privatekey, String Text, Ref   String Signaturetext)
{

Byte [] Bytetext = Convert. frombase64string (text );
Rsacryptoserviceprovider rsaprovider =   New Rsacryptoserviceprovider ();
Rsaprovider. fromxmlstring (privatekey );
Rsapkcs1signatureformatter rsasignatureformatter =   New Rsapkcs1signatureformatter (rsaprovider );
Rsasignatureformatter. sethashalgorithm ( " MD5 " );
Byte [] Bytesignaturetext = Rsasignatureformatter. createsignature (bytetext );
Signaturetext = Convert. tobase64string (bytesignaturetext );

}

///   <Summary>
/// Verify signature
///   </Summary>
///   <Param name = "key"> </param>
///   <Param name = "text"> Original Text </Param>
///   <Param name = "signaturetext"> Signed text </Param>
///   <Returns> True: Correct; false: Error </Returns>
Public   Static   Bool Signaturedeformatter ( String Publickey, String Text, String Signaturetext)
{
Byte [] Bytetext = Convert. frombase64string (text );
Byte [] Bytesignaturetext = Convert. frombase64string (signaturetext );
Rsacryptoserviceprovider rsaprovider =   New Rsacryptoserviceprovider ();
Rsaprovider. fromxmlstring (publickey );
Rsapkcs1signaturedeformatter rsasignaturedeformatter =   New Rsapkcs1signaturedeformatter (rsaprovider );
Rsasignaturedeformatter. sethashalgorithm ( " MD5 " );
Return Rsasignaturedeformatter. verifysignature (bytetext, bytesignaturetext );
}

}
}