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authorMark Haines <mjark@negativecurvature.net>2015-02-26 16:40:56 +0000
committerMark Haines <mjark@negativecurvature.net>2015-02-26 16:40:56 +0000
commite50ac707316ea6d8059f7036322450727773952d (patch)
tree0cd42bcd79e20f54f4944522576a1e35e231ddd5 /python-src/curve25519/keys.py
Squashed 'lib/curve25519-donna/' content from commit 28772f3
git-subtree-dir: lib/curve25519-donna git-subtree-split: 28772f37a4b8a57ab9439b9e79b19f9abee686da
Diffstat (limited to 'python-src/curve25519/keys.py')
-rw-r--r--python-src/curve25519/keys.py46
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
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+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