C # using RSA certificate file encryption and decryption examples

Original: C # using RSA certificate file encryption and decryption example

Modify the example on MSDN so that it can be encrypted and decrypted through the RSA certificate file, and encounter a minor problem in the middle.

Q: When executing the Exportparameters () method, the return Cryptographicexception: The item is not suitable to be used in a specified state (key is not valid for using in specified).

A: When you import a certificate with a private key, you need to mark "private key exportable" with the "x509keystorageflags" parameter.

x509certificate2 prvcrt = new x509certificate2 (@ "X:\path\to\CA.pfx", "*** password*** " , x509keystorageflags.exportable);

The following is an example program:

View Code

usingSystem;usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Text;namespaceteatapp_crypto{usingSystem; usingSystem.Security.Cryptography; usingSystem.Security.Cryptography.X509Certificates; usingSystem.Text; classRsacspsample {Static voidMain () {Try            {                //Create a unicodeencoder to convert between byte array and string.UnicodeEncoding Byteconverter =Newunicodeencoding (); //Create byte arrays to hold original, encrypted, and decrypted data.                byte[] Datatoencrypt = Byteconverter.getbytes ("Data to Encrypt"); byte[] EncryptedData; byte[] decrypteddata; X509Certificate2 PUBCRT=NewX509Certificate2 (@"X:\PATH\TO\CA.CRT"); RSACryptoServiceProvider PubKey=(RSACryptoServiceProvider) pubcrt.                Publickey.key; X509Certificate2 PRVCRT=NewX509Certificate2 (@"X:\path\to\CA.pfx","***password***", x509keystorageflags.exportable); RSACryptoServiceProvider Prvkey=(RSACryptoServiceProvider) prvcrt.                Privatekey; //Create A new instance of RSACryptoServiceProvider to generate//Public and private key data. //using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider ())//{                    //Console.WriteLine (RSA.                    Toxmlstring (false)); //Pass The data to ENCRYPT, and the public key information//(using Rsacryptoserviceprovider.exportparameters (false),//And A Boolean flag specifying no OAEP padding.EncryptedData = Rsaencrypt (Datatoencrypt, PubKey. Exportparameters (false),false); Console.WriteLine ("Encrypted plaintext: {0}", Convert.tobase64string (EncryptedData)); //Pass The data to DECRYPT, the private key information//(using Rsacryptoserviceprovider.exportparameters (true),//And A Boolean flag specifying no OAEP padding.Decrypteddata = Rsadecrypt (EncryptedData, Prvkey. Exportparameters (true),false); //Display The decrypted plaintext to the console.Console.WriteLine ("decrypted plaintext: {0}", Byteconverter.getstring (Decrypteddata)); //}Prvkey.                Clear (); PubKey.                Clear ();            Console.read (); }            Catch(ArgumentNullException) {//Catch This exception in case the encryption did//Not succeed.Console.WriteLine ("encryption failed."); }        }        Static  Public byte[] Rsaencrypt (byte[] Datatoencrypt, RSAParameters Rsakeyinfo,BOOLdooaeppadding) {            Try            {                byte[] EncryptedData; //Create A new instance of RSACryptoServiceProvider.                using(RSACryptoServiceProvider RSA =NewRSACryptoServiceProvider ()) {                    //Import the RSA Key information. this is only needs//toinclude the public key information.RSA.                    ImportParameters (Rsakeyinfo); //Encrypt the passed byte array and specify OAEP padding. //OAEP padding is only available on Microsoft Windows XP or//later. EncryptedData =RSA.                Encrypt (Datatoencrypt, dooaeppadding); }                returnEncryptedData; }            //Catch and display a cryptographicexception//to the console.            Catch(Cryptographicexception e) {Console.WriteLine (e.message); return NULL; }        }        Static  Public byte[] Rsadecrypt (byte[] dataToDecrypt, RSAParameters Rsakeyinfo,BOOLdooaeppadding) {            Try            {                byte[] decrypteddata; //Create A new instance of RSACryptoServiceProvider.                using(RSACryptoServiceProvider RSA =NewRSACryptoServiceProvider ()) {                    //Import the RSA Key information. This needs//To include the private key information.RSA.                    ImportParameters (Rsakeyinfo); //Decrypt the passed byte array and specify OAEP padding. //OAEP padding is only available on Microsoft Windows XP or//later. Decrypteddata =RSA.                Decrypt (dataToDecrypt, dooaeppadding); }                returnDecrypteddata; }            //Catch and display a cryptographicexception//to the console.            Catch(Cryptographicexception e) {Console.WriteLine (e.tostring ()); return NULL; }        }    }}

C # using RSA certificate file encryption and decryption examples