8_DSA算法

Posted 2021-06-18 H3rmesk1t

实验题目

DSA算法

实验目的和要求

熟悉MPIR大数库的用法，理解和学会DSA数字签名算法，提高一般数字签名算法的设计能力
实验环境
PyCharm

实验内容

生成满足要求公私钥，随机选取消息，生成DSA签名

算法描述

实验步骤
1.生成公钥的各个部分pubkey->alpha，pubkey->p，pubkey->q，pubkey->y；
2.生成私钥prikey；
3.随机生成消息m；
4.生成签名的各个部分

实验代码

# -*- coding: utf-8 -*-
# @Time    : 2021/5/12 20:12
# @Author  : H3rmesk1t
# @FileName: DSA算法.py
# @Software: PyCharm
# @Blog    ：https://blog.csdn.net/LYJ20010728/
#encoding utf-8
from Cryptodome.Random import random
from Cryptodome.PublicKey import DSA
from Cryptodome.Hash import SHA256
from Cryptodome.Signature import DSS

# Create a new DSA key
def getPublicKey():
    key = DSA.generate(2048)
    f = open("public_key.pem", "wb+")
    f.write(key.publickey().export_key())
    f.close()
    return key

# Sign a message
def signMessage(message,key):
    hash_obj = SHA256.new(message)
    signer = DSS.new(key, 'fips-186-3')
    signature = signer.sign(hash_obj)
    return signature

# Load the public key
def loadPublicKey(message):
    f = open("public_key.pem", "r")
    hash_obj = SHA256.new(message)
    pub_key = DSA.import_key(f.read())
    verifier = DSS.new(pub_key, 'fips-186-3')
    return hash_obj,verifier

# Verify the authenticity of the message
def verifyAuthenticityOfMessage(hash_obj,verifier,signature):
    try:
        verifier.verify(hash_obj, signature)
        print("ResultOfVerify：The message is authentic.")
    except ValueError:
        print("ResultOfVerify：The message is not authentic.")

# print parameter we got
def printParameter(message,key,hash_obj,verifier,signature):
    print(f"Message is {message}")
    print(f"Key is {key}")
    print(f"Hash_obj is {hash_obj}")
    print(f"Verifier is {verifier}")
    print(f"Signature is {signature}")

if __name__ == '__main__':
    message = b"H3rmesk1t_is_a_cool_boy"
    key = getPublicKey()
    signature = signMessage(message=message, key=key)
    hash_obj, verifier = loadPublicKey(message=message)
    printParameter(message=message, key=key, hash_obj=hash_obj, verifier=verifier, signature=signature)
    verifyAuthenticityOfMessage(hash_obj=hash_obj, verifier=verifier, signature=signature)