What OpenSource System.Security.Cryptography.Pkcs Alternatives are there?

I am trying to use PKCS on mono. The only issue is that after running MoMa, the scan report showed the the following:

Calling Method            Method with [MonoTodo]   
Byte[] Sign (Byte[])      void SignedCms.ComputeSignature (CmsSigner)    
Byte[] Sign (Byte[])      Byte[] SignedCms.Encode ()    
Byte[] Envelope (Byte[])  void EnvelopedCms.Encrypt (CmsRecipient)    
Byte[] Envelope (Byte[])  Byte[] EnvelopedCms.Encode ()

As you can see, the required methods I need to use, are not yet implemented on Mono. Does anyone know a workaround to this, may be a patch, or does anyone know of any open source libraries which would a开发者_StackOverflow社区llow me to achieve similar results as the System.Security.Cryptography.Pkcs.CmsSigner module.

TIA,

Andrew

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BouncyCastle has a C# version and is supported on Mono. It also includes API for CMS Generators and Processors.