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from .utils.compatibility import *
from .utils.der import parse, encodeConstructed, encodePrimitive, DerFieldType
from .utils.binary import hexFromByteString, byteStringFromHex, base64FromByteString, byteStringFromBase64
class Signature:
def __init__(self, r, s, recoveryId=None):
self.r = r
self.s = s
self.recoveryId = recoveryId
def toDer(self, withRecoveryId=False):
hexadecimal = self._toString()
encodedSequence = byteStringFromHex(hexadecimal)
if not withRecoveryId:
return encodedSequence
return toBytes(chr(27 + self.recoveryId)) + encodedSequence
def toBase64(self, withRecoveryId=False):
return base64FromByteString(self.toDer(withRecoveryId))
@classmethod
def fromDer(cls, string, recoveryByte=False):
recoveryId = None
if recoveryByte:
recoveryId = string[0] if isinstance(string[0], intTypes) else ord(string[0])
recoveryId -= 27
string = string[1:]
hexadecimal = hexFromByteString(string)
return cls._fromString(string=hexadecimal, recoveryId=recoveryId)
@classmethod
def fromBase64(cls, string, recoveryByte=False):
der = byteStringFromBase64(string)
return cls.fromDer(der, recoveryByte)
def _toString(self):
return encodeConstructed(
encodePrimitive(DerFieldType.integer, self.r),
encodePrimitive(DerFieldType.integer, self.s),
)
@classmethod
def _fromString(cls, string, recoveryId=None):
r, s = parse(string)[0]
return Signature(r=r, s=s, recoveryId=recoveryId)
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