Squashed 'lib/curve25519-donna/' content from commit 28772f3

git-subtree-dir: lib/curve25519-donna
git-subtree-split: 28772f37a4b8a57ab9439b9e79b19f9abee686da

1 files changed, 46 insertions, 0 deletions

diff --git a/python-src/curve25519/keys.py b/python-src/curve25519/keys.py
new file mode 100644
index 0000000..e131dac
--- /dev/null
+++ b/python-src/curve25519/keys.py
@@ -0,0 +1,46 @@
+from . import _curve25519
+from hashlib import sha256
+import os
+
+# the curve25519 functions are really simple, and could be used without an
+# OOP layer, but it's a bit too easy to accidentally swap the private and
+# public keys that way.
+
+def _hash_shared(shared):
+    return sha256(b"curve25519-shared:"+shared).digest()
+
+class Private:
+    def __init__(self, secret=None, seed=None):
+        if secret is None:
+            if seed is None:
+                secret = os.urandom(32)
+            else:
+                secret = sha256(b"curve25519-private:"+seed).digest()
+        else:
+            assert seed is None, "provide secret, seed, or neither, not both"
+        if not isinstance(secret, bytes) or len(secret) != 32:
+            raise TypeError("secret= must be 32-byte string")
+        self.private = _curve25519.make_private(secret)
+
+    def serialize(self):
+        return self.private
+
+    def get_public(self):
+        return Public(_curve25519.make_public(self.private))
+
+    def get_shared_key(self, public, hashfunc=None):
+        if not isinstance(public, Public):
+            raise ValueError("'public' must be an instance of Public")
+        if hashfunc is None:
+            hashfunc = _hash_shared
+        shared = _curve25519.make_shared(self.private, public.public)
+        return hashfunc(shared)
+
+class Public:
+    def __init__(self, public):
+        assert isinstance(public, bytes)
+        assert len(public) == 32
+        self.public = public
+
+    def serialize(self):
+        return self.public