Merge pull request #778 from Atheros1/pointMult-exception

handle OpenSSL.EC_KEY_get0_group() exception

src/highlevelcrypto.py

@@ -40,6 +40,15 @@ def verify(msg,sig,hexPubkey):
 
 # Does an EC point multiplication; turns a private key into a public key.
 def pointMult(secret):
+    while True:
+        try:
+            """
+            Evidently, this type of error can occur very rarely:
+            
+            File "highlevelcrypto.py", line 54, in pointMult
+              group = OpenSSL.EC_KEY_get0_group(k)
+            WindowsError: exception: access violation reading 0x0000000000000008
+            """
             k = OpenSSL.EC_KEY_new_by_curve_name(OpenSSL.get_curve('secp256k1'))
             priv_key = OpenSSL.BN_bin2bn(secret, 32, None)
             group = OpenSSL.EC_KEY_get0_group(k)
@@ -57,3 +66,10 @@ def pointMult(secret):
             OpenSSL.BN_free(priv_key)
             OpenSSL.EC_KEY_free(k)
             return mb.raw
+
+        except Exception as e:
+            import traceback
+            import time
+            traceback.print_exc()
+            time.sleep(0.2)
+