static void Main(string[] args)
{
try
{
X509Certificate2 myCert =
LoadCertificate(StoreLocation.CurrentUser,
"CN=test");
string myText = "This is the text I wish to encrypt";
Console.WriteLine("UNENCRYPTED:
" + myText);
string encrypted =
Encrypt(myCert, myText);
Console.WriteLine("ENCRYPTED:
" + encrypted);
string decrypted =
Decrypt(myCert, encrypted);
Console.WriteLine("DECRYPTED:
" + decrypted);
}
catch (Exception e)
{
Console.WriteLine("EXCEPTION:
{0}", e.Message);
}
}
public static
X509Certificate2
LoadCertificate(StoreLocation storeLocation,
string certificateName)
{
X509Store store
= new X509Store(storeLocation);
store.Open(OpenFlags.ReadOnly);
X509Certificate2Collection certCollection =
store.Certificates;
X509Certificate2
cert =
certCollection.Cast<X509Certificate2>().FirstOrDefault
(c =>
c.Subject == certificateName);
if (cert == null)
Console.WriteLine("NO
Certificate named " +
certificateName + " was
found in your certificate store");
store.Close();
return cert;
}
private static string Encrypt(X509Certificate2
x509, string stringToEncrypt)
{
if (x509 == null || string.IsNullOrEmpty(stringToEncrypt))
throw new Exception("A x509 certificate and string for encryption must
be provided");
RSACryptoServiceProvider
rsa = (RSACryptoServiceProvider)x509.PublicKey.Key;
byte[]
bytestoEncrypt = ASCIIEncoding.ASCII.GetBytes(stringToEncrypt);
byte[]
encryptedBytes = rsa.Encrypt(bytestoEncrypt, false);
return Convert.ToBase64String(encryptedBytes);
}
private static string
Decrypt(X509Certificate2 x509, string stringTodecrypt)
{
if (x509 == null || string.IsNullOrEmpty(stringTodecrypt))
throw new Exception("A x509 certificate and string for decryption must
be provided");
if
(!x509.HasPrivateKey)
throw new Exception("x509 certicate does not contain a private key for
decryption");
RSACryptoServiceProvider rsa = (RSACryptoServiceProvider)x509.PrivateKey;
byte[]
bytestodecrypt = Convert.FromBase64String(stringTodecrypt);
byte[] plainbytes =
rsa.Decrypt(bytestodecrypt, false);
System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
return enc.GetString(plainbytes);
}
