# Copyright (c) 2015, Hubert Kario
#
# See the LICENSE file for legal information regarding use of this file.
"""Methods for dealing with ECC points"""
import ecdsa
from .compat import ecdsaAllCurves
[docs]
def getCurveByName(curveName):
"""Return curve identified by curveName"""
curveMap = {'secp256r1':ecdsa.NIST256p,
'secp384r1':ecdsa.NIST384p,
'secp521r1':ecdsa.NIST521p,
'secp256k1':ecdsa.SECP256k1,
'brainpoolP256r1': ecdsa.BRAINPOOLP256r1,
'brainpoolP384r1': ecdsa.BRAINPOOLP384r1,
'brainpoolP512r1': ecdsa.BRAINPOOLP512r1}
if ecdsaAllCurves:
curveMap['secp224r1'] = ecdsa.NIST224p
curveMap['secp192r1'] = ecdsa.NIST192p
if curveName in curveMap:
return curveMap[curveName]
else:
raise ValueError("Curve of name '{0}' unknown".format(curveName))
[docs]
def getPointByteSize(point):
"""Convert the point or curve bit size to bytes"""
curveMap = {ecdsa.NIST256p.curve: 256//8,
ecdsa.NIST384p.curve: 384//8,
ecdsa.NIST521p.curve: (521+7)//8,
ecdsa.SECP256k1.curve: 256//8,
ecdsa.BRAINPOOLP256r1.curve: 256//8,
ecdsa.BRAINPOOLP384r1.curve: 384//8,
ecdsa.BRAINPOOLP512r1.curve: 512//8}
if ecdsaAllCurves:
curveMap[ecdsa.NIST224p.curve] = 224//8
curveMap[ecdsa.NIST192p.curve] = 192//8
if hasattr(point, 'curve'):
if callable(point.curve):
return curveMap[point.curve()]
else:
return curveMap[point.curve]
raise ValueError("Parameter must be a curve or point on curve")