module JWT::JWA::Rsa

def sign(algorithm, msg, key)
  unless key.is_a?(OpenSSL::PKey::RSA)
    raise EncodeError, "The given key is a #{key.class}. It has to be an OpenSSL::PKey::RSA instance"
  end
  key.sign(OpenSSL::Digest.new(algorithm.sub('RS', 'sha')), msg)
end

def verify(algorithm, public_key, signing_input, signature)
  public_key.verify(OpenSSL::Digest.new(algorithm.sub('RS', 'sha')), signature, signing_input)
rescue OpenSSL::PKey::PKeyError
  raise JWT::VerificationError, 'Signature verification raised'
end