[Suggestion] RSA Signing

It would be good to have RSA signature functions along with encryption in Advanced Cipher Block

Signing is just encryption with private key instead of public.

Then how i could verify sign? :)

Decrypt with public. Keys are interchangeable. The one issue here is the absence of hash functions in Computronics, and, possibly, ASN.1 structure of signature, but ASN.1 can be generated in Lua since it isn't much complex, and hash functions are present in core OpenComputers, if you are using it.