transaction.py

from collections import OrderedDict

import binascii
import transactionOut
import transactionIn

import Crypto
import Crypto.Random
from Crypto.Hash import SHA
from Crypto.PublicKey import RSA
from Crypto.Signature import PKCS1_v1_5

class Transaction:

    def __init__(self, sender_address, sender_id, recipient_address, recipient_id,value,NBCs,transactionIn,transactionId=None,transactionOut = None,signature = None):
        #self.sender_address: To public key του wallet από το οποίο προέρχονται τα χρήματα
        self.sender_address = sender_address
        #self.receiver_address: To public key του wallet στο οποίο θα καταλήξουν τα χρήματα
        self.receiver_address = recipient_address
        #self.amount: το ποσό της συναλλαγής
        self.amount = value
        #NBCs τα coins που εστάλησαν τελικά
        self.NBCs = NBCs
        #self.transaction_id: το hash του transaction (hexadecimal format)
        if (transactionId):
            self.transaction_id = transactionId
        else:
            self.transaction_id = SHA.new((str(sender_address)+str(recipient_address)+str(value)).encode()).hexdigest()
        #self.transaction_inputs: λίστα από Transaction Input 
        self.transaction_inputs = transactionIn
        #self.transaction_outputs: λίστα από Transaction Output
        if (transactionOut == None):
            self.create_out()
        else:
            self.transaction_outputs = transactionOut
        #self.signature
        self.signature = signature
        #sender id
        self.sender = sender_id
        #receiver id
        self.receiver = recipient_id


    def sign_transaction(self,private_key):
        #Sign transaction with private key
        private_key = RSA.importKey(private_key)
        sender = PKCS1_v1_5.new(private_key)
        hash = SHA.new(str(self.__dict__).encode('utf8'))
        self.signature = binascii.hexlify(sender.sign(hash)).decode('ascii')

    def validate_transaction(self):
        #validate using sender's public key
        key = RSA.importKey(self.sender_address)
        message_hash = SHA.new(self.transaction_id.encode('utf-8'))
        verifier = PKCS1_v1_5.new(key)
        try:
            verifier.verify(message_hash, self.signature)
            return True
        except (ValueError, TypeError):
            return False

    #we create the two outputs on regarding the receiver and one regarding the sender
    def create_out(self):
        rec_out = transactionOut.TransactionOutput(self.transaction_id,self.receiver_address,self.amount)
        self.transaction_outputs = [rec_out]

        #check for change
        if self.NBCs > self.amount:
            send_out = transactionOut.TransactionOutput(self.transaction_id,self.sender_address,self.NBCs-self.amount)
            self.transaction_outputs.append(send_out)

    def stringify(self):
        return str(self.__dict__)