实现HMACSHA1时出现问题，给出了错误的哈希？

Question

我试图用python实现我自己的HMAC-SHA1函数，但它似乎总是在最后给我错误的校验和，我不明白为什么

""" An Hmac Implementation of SHA-1 """
from Crypto.Hash import SHA1

hasher = SHA1.new()

password = b"test"
message = b"NAME"

pad_length = 64 - len(password)
key = bytes(pad_length) + password

ipad_num = "01011100" * 64
opad_num = "00110110" * 64

ipad = int.from_bytes(key, byteorder="big") ^ int(ipad_num, base=2)
opad = int.from_bytes(key, byteorder="big") ^ int(opad_num, base=2)

ipad = int.to_bytes(ipad, length=64, byteorder="big")
opad = int.to_bytes(opad, length=64, byteorder="big")

hasher.update(ipad + message)
inner_hash = hasher.digest()
print("inner hash {}".format(inner_hash.hex()))

hasher = SHA1.new()
hasher.update(opad + inner_hash)
print("final hash {}".format(hasher.hexdigest()))

应该给我这个校验和： 对于消息=NAME密码=test

3e0f1cc6c2d787afe49345986212f60d3d4d300d

但是它给了我这个校验和

7d6b1ba137a44ee9e083d8e3ba5a84fd739751f4

Answer 1

我建议您使用python提供的hmac库，除非您正在学习密码学

以下是固定代码：

""" An Hmac Implementation of SHA-1 """
from Crypto.Hash import SHA1

hasher = SHA1.new()

password = b"test"
message = b"NAME"

pad_length = 64 - len(password) # TODO: support longer key
key = password + bytes(pad_length) # padding should be on the right

ipad_num = "00110110" * 64 # ipad should be 0x36
opad_num = "01011100" * 64 # opad should be 0x5c

ipad = int.from_bytes(key, byteorder="big") ^ int(ipad_num, base=2)
opad = int.from_bytes(key, byteorder="big") ^ int(opad_num, base=2)

ipad = int.to_bytes(ipad, length=64, byteorder="big")
opad = int.to_bytes(opad, length=64, byteorder="big")

hasher.update(ipad + message)
inner_hash = hasher.digest()
print("inner hash {}".format(inner_hash.hex()))

hasher = SHA1.new()
hasher.update(opad + inner_hash)
print("final hash {}".format(hasher.hexdigest()))