opaquification part 1

rowers/opaque.py

@@ -0,0 +1,59 @@
+import struct
+import base64
+
+from rowsandall_app.settings import (
+    C2_CLIENT_ID, C2_REDIRECT_URI, C2_CLIENT_SECRET,
+    STRAVA_CLIENT_ID, STRAVA_REDIRECT_URI, STRAVA_CLIENT_SECRET,
+    POLAR_CLIENT_ID, POLAR_REDIRECT_URI, POLAR_CLIENT_SECRET,
+    SPORTTRACKS_CLIENT_ID, SPORTTRACKS_REDIRECT_URI,
+    SPORTTRACKS_CLIENT_SECRET,
+    UNDERARMOUR_CLIENT_ID, UNDERARMOUR_REDIRECT_URI,
+    UNDERARMOUR_CLIENT_SECRET,UNDERARMOUR_CLIENT_KEY,
+    RUNKEEPER_CLIENT_ID,RUNKEEPER_REDIRECT_URI,RUNKEEPER_CLIENT_SECRET,
+    TP_CLIENT_ID,TP_REDIRECT_URI,TP_CLIENT_KEY,TP_CLIENT_SECRET,
+    BRAINTREE_MERCHANT_ID,BRAINTREE_PUBLIC_KEY,BRAINTREE_PRIVATE_KEY,
+    PAYMENT_PROCESSING_ON,OPAQUE_SECRET_KEY
+    )
+
+class OpaqueEncoder:
+    """
+    Opaque ID encoder.
+    Translates between 32-bit integers (such as resource IDs) and obfuscated
+    scrambled values, as a one-to-one mapping. Supports hex and base64 url-safe
+    string representations. Expects a secret integer key in the constructor.
+    (c) 2011 Marek Z. @marekweb
+    """
+
+    def __init__(self, key):
+        self.key = key
+        self.extra_chars = b'.-';
+
+    def transform(self, i):
+        """Produce an integer hash of a 16-bit integer, returning a transformed 16-bit integer."""
+        i = (self.key ^ i) * 0x9e3b
+        return i >> (i & 0xf) & 0xffff
+
+    def transcode(self, i):
+        """Reversibly transcode a 32-bit integer to a scrambled form, returning a new 32-bit integer."""
+        r = i & 0xffff
+        l = i >> 16 & 0xffff ^ self.transform(r)
+        return ((r ^ self.transform(l)) << 16) + l
+
+    def encode_hex(self, i):
+        """Transcode an integer and return it as an 8-character hex string."""
+        return "%08x" % self.transcode(i)
+
+    def encode_base64(self, i):
+        """Transcode an integer and return it as a 6-character base64 string."""
+        return base64.b64encode(struct.pack('!L', self.transcode(i)), self.extra_chars)[:6]
+
+    def decode_hex(self, s):
+        """Decode an 8-character hex string, returning the original integer."""
+        return self.transcode(int(s, 16))
+
+    def decode_base64(self, s):
+        """Decode a 6-character base64 string, returning the original integer."""
+        return self.transcode(struct.unpack('!L', base64.b64decode(s + '==', self.extra_chars))[0])
+
+
+encoder = OpaqueEncoder(OPAQUE_SECRET_KEY)