support SHA384/512 signatures with RS384/RS512 algorithms

Author: brentru

README.rst

@@ -13,7 +13,9 @@ Introduction
     :target: https://travis-ci.com/adafruit/Adafruit_CircuitPython_JWT
     :alt: Build Status
 
-JSON Web Token Authentication 
+JSON Web Token (JWT) Authentication module for CircuitPython. JSON Web Tokens are an open, industry standard
+`RFC 7519 <https://tools.ietf.org/html/rfc7519>`_ method for representing claims securely between two parties. Module
+includes methods for JWT generation and verification.
 
 
 Dependencies
@@ -31,9 +33,6 @@ Installing from PyPI
 .. note:: This library is not available on PyPI yet. Install documentation is included
    as a standard element. Stay tuned for PyPI availability!
 
-.. todo:: Remove the above note if PyPI version is/will be available at time of release.
-   If the library is not planned for PyPI, remove the entire 'Installing from PyPI' section.
-
 On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally `from
 PyPI <https://pypi.org/project/adafruit-circuitpython-jwt/>`_. To install for current user:
 

adafruit_jwt.py

@@ -110,15 +110,22 @@ def generate(claims, private_key_data=None, algo=None):
         # Compute the signature
         if algo == "none":
             jwt = "{}.{}".format(jose_header, claims)
-        elif algo in ("RS256", "RS384", "RS512"):
+            return jwt
+        if algo == "RS256":
             signature = STRING_TOOLS.urlsafe_b64encode(
                 sign(payload, priv_key, "SHA-256"))
-            jwt = payload + "." + signature
+        elif algo == "RS384":
+            signature = STRING_TOOLS.urlsafe_b64encode(
+                sign(payload, priv_key, "SHA-384"))
+        elif algo == "RS512":
+            signature = STRING_TOOLS.urlsafe_b64encode(
+                sign(payload, priv_key, "SHA-512"))
         else:
             raise TypeError(
                 "Adafruit_JWT is currently only compatible with algorithms within"
                 "the Adafruit_RSA module."
             )
+        jwt = payload + "." + signature
         return jwt