2 files changed, 22 insertions, 0 deletions
diff --git a/jwcrypto/__init__.py b/jwcrypto/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/jwcrypto/__init__.py
diff --git a/jwcrypto/common.py b/jwcrypto/common.py
new file mode 100644
index 0000000..e348b44
--- /dev/null
+++ b/jwcrypto/common.py
@@ -0,0 +1,22 @@
+# Copyright (C) 2015 JWCrypto Project Contributors - see LICENSE file
+
+from base64 import urlsafe_b64encode, urlsafe_b64decode
+
+
+# Padding stripping versions as described in
+# draft-ietf-jose-json-web-signature-41 appendix C
+
+
+def base64url_encode(payload):
+    return urlsafe_b64encode(payload).rstrip('=')
+
+
+def base64url_decode(payload):
+    l = len(payload) % 4
+    if l == 2:
+        payload += '=='
+    elif l == 3:
+        payload += '='
+    elif l != 0:
+        raise ValueError('Invalid base64 string')
+    return urlsafe_b64decode(payload)