How do I read the digital signature information from a signed .Net assembly?

I am writing an assembly information application to be used in our software build process and am trying to read the digital signature information from a signed .Net assembly.

I want to do in my C# code what Windows Explorer can do by right-clicking a signed assembly and selecting the "Digital Signatures" tab and then clicking the Details button. e.g.

Has anyone got an idea how to do this programmatically in C#? I am currently using the Mono Cecil library to get the rest of the information from the assembly. Your help will be most appreciated.