Source code for ecpy.keys

# Copyright 2016 Cedric Mesnil <cedric.mesnil@ubinity.com>, Ubinity SAS
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

#python 2 compatibility
from builtins import int,pow

import ecpy.curves

class ECPublicKey:
    """ Public EC key.
    
    Can be used for both ECDSA and EDDSA signature

    Attributes:
        W (Point): public key point

    Args:
       W (Point): public key value
    """
    
    def __init__(self, W):
        self.W = W

    @property
    def curve(self):
        return self.W.curve

    def __str__(self):
        return "ECPublicKey:\n  x: %x\n  y: %x" % (self.W.x,self.W.y)
        
class ECPrivateKey:
    """ Public EC key.
    
    Can be used for both ECDSA and EDDSA signature

    Attributes
        d (int)       : private key scalar
        curve (Curve) : curve

    Args:
       d (int):        private key value
       curve (Curve) : curve
    """
    
    def __init__(self, d,curve):
        self.d = int(d)
        self.curve = curve
    
    def get_public_key(self):
        """ Returns the public key corresponding to this private key 
        
        This method considers the private key the generator multiplier and
        return pv*Generator in all cases.
        
        For specific derivation such as in EdDSA, see ecpy.eddsa.get_public_key

        Returns:
           ECPublicKey : public key
        """
        W = self.d*self.curve.generator
        return ECPublicKey(W)

    def __str__(self):
        return "ECPrivateKey:\n  d: %x" % self.d