I am trying to use the Yelp API in a Swift iOS app, but am new to encryption. I understand that I am supposed to encrypt the signature with SHA1, but can't find good resources for doing this in Swift/Xcode.
Additionally, the Yelp docs say I am supposed to pass the signature value as "The generated request signature, signed with the oauth_token_secret obtained". I don't understand what is meant by "signed with". Link to the docs here: Yelp Authentication
Any help would be hugely appreciated.