title: How create bouncycastle CmsSignedData with device like token, smart card?
body: <p>i have a token (security device)
  and can :
  read Certificate 
  Sign data (no private key available)</p>
  
  <p>but all CmsSignedDataGenerator need private key</p>
  
  <p>i have
  public key, certificate, signature (signed content with rsa_sha_1)</p>
  
  <p>how generate CmsSignedData without private key (only signature, public key, certificate)?
  any sample in c#? that can help me?</p>