Question

我正在编写一个简单的工具，可以让我快速检查下载的ISO文件的MD5哈希值。这是我的算法：

import sys
import hashlib

def main():
    filename = sys.argv[1] # Takes the ISO 'file' as an argument in the command line
    testFile = open(filename, "r") # Opens and reads the ISO 'file'

    # Use hashlib here to find MD5 hash of the ISO 'file'. This is where I'm having problems
    hashedMd5 = hashlib.md5(testFile).hexdigest()

    realMd5 = input("Enter the valid MD5 hash: ") # Promt the user for the valid MD5 hash

    if (realMd5 == hashedMd5): # Check if valid
        print("GOOD!")
    else:
        print("BAD!!")

main()

当我尝试获取文件的MD5哈希时，我的问题出现在第9行。我得到了Type Error：对象，支持所需的缓冲区API。谁能说明如何使这个功能发挥作用？

Answer 1

hashlib.md5创建的对象不接受文件对象。您需要一次一个地提供数据，然后请求哈希摘要。

import hashlib

testFile = open(filename, "rb")
hash = hashlib.md5()

while True:
    piece = testFile.read(1024)

    if piece:
        hash.update(piece)
    else: # we're at end of file
        hex_hash = hash.hexdigest()
        break

print hex_hash # will produce what you're looking for

Answer 2

您需要阅读文件：

import sys
import hashlib

def main():
    filename = sys.argv[1] # Takes the ISO 'file' as an argument in the command line
    testFile = open(filename, "rb") # Opens and reads the ISO 'file'

    # Use hashlib here to find MD5 hash of the ISO 'file'. This is where I'm having problems
    m = hashlib.md5()
    while True:
        data = testFile.read(4*1024*1024)
        if not data: break
        m.update(data)
    hashedMd5 = m.hexdigest()
    realMd5 = input("Enter the valid MD5 hash: ") # Promt the user for the valid MD5 hash

    if (realMd5 == hashedMd5): # Check if valid
        print("GOOD!")
    else:
        print("BAD!!")

main()

您可能需要以二进制（“rb”）打开文件并以块的形式读取数据块。 ISO文件可能太大而无法放入内存中。

如何使用Python找到ISO文件的MD5哈希？

2 个答案: