I want to get my certificate from the SPC system store, Hash a data string and then create a signature of that Hashed string using MD5 as the hashing algorithm. In C++ I doing the following:

CertOpenStore(...)
CertFindCertificateInStore(...)
CryptAcquireCertificatePrivateKey(...)
CryptCreateHash(...)
CryptHashData(...)
CryptSignHash(...)

In the Mentais library I can do the first bit fine:
cs = new CertificateStore("SPC");
cert = cs.FindCertificateBySubjectString("PhoneThemes");

How do I do the next bit? There seems to be a really good function called "CreateSignature" but this is in an internal class ("MD5SHA1CryptoServiceProvider") and doesn't just do MD5 hashing. What's the best way of going about this?

(Great resource BTW)

Thanks

Jim

The hashing- and signature classes are part of the normal .NET framework. Typically you'd use the MD5CryptoServiceProvider or SHA1CryptoServiceProvider class [from the System.Security.Cryptography namespace] to hash data and then one of the AsymmetricSignatureFormatters to sign it.

Here's some code that may help you on your way:

using System;
using System.Security.Cryptography;
using Org.Mentalis.Security.Certificates;

string text = ...;
byte[] text_bytes = Encoding.UTF8.GetBytes(text);
Certificate spc = ...;

MD5 md5 = MD5.Create();
md5.TransformFinalBlock(text_bytes, 0, text_bytes.Length);

AsymmetricSignatureFormatter asf = new RSAPKCS1SignatureFormatter(spc.PrivateKey);

byte[] signature = asf.CreateSignature(md5);