The Certificate Services component allows you to encrypt, decrypt, sign or verify the contents of a document or message, based upon
X509 Certificates. This component can be used on the control flow surface, and is straightforward to configure :

You simply select the operation, the certificate, the variable containing the source content and the variable to contain the result content (which can be the same variable). Document variables can be strings (in which case the Encoding property, accessible only in the Visual Studio Properties pane, is used to define the conversion to binary form), or objects (in which case they are regarded as byte arrays).