add crypto module

1 files changed, 33 insertions, 0 deletions

diff --git a/crypto.py b/crypto.py
new file mode 100644
index 0000000..0274ec1
--- /dev/null
+++ b/crypto.py
@@ -0,0 +1,33 @@
+import M2Crypto.RSA
+import M2Crypto.EVP
+import time, sys
+import base64
+
+default_alg = 'sha256'
+
+def sign(keyfile, data, alg = default_alg):
+	digest = M2Crypto.EVP.MessageDigest(alg)
+	digest.update(data)
+	digval = digest.final()
+
+	key = M2Crypto.RSA.load_key(keyfile)
+	signature = key.sign(digval, algo = alg)
+	return base64.urlsafe_b64encode(signature)
+
+def verify(keyfile, data, sig, alg = default_alg):
+	digest = M2Crypto.EVP.MessageDigest(alg)
+	digest.update(data)
+	digval = digest.final()
+
+	key = M2Crypto.RSA.load_pub_key(keyfile)
+
+	rawsig = base64.urlsafe_b64decode(sig)
+	return bool(key.verify(digval, rawsig, algo = alg))
+
+if __name__ == '__main__':
+	if len(sys.argv) != 3:
+		print 'pls give private + public key as arg.'
+		sys.exit(1)
+	sig = sign(sys.argv[1], 'test')
+	vfy = verify(sys.argv[2], 'test', sig)
+	print '(%d) %s %s' % (len(sig), vfy, sig)