爲了確保從網上下載的文件或程序完整並且沒有被篡改,一般官網上都會給出文件的md5或sha1。我們拿到一個軟件,第一步應當是校驗這個值與官網給的是否一致,如果不一致的話就趕緊刪掉吧。
在Mac上計算一個文件的md5, sha1, crc32:
命令 | 輸出 |
---|---|
$ md5 shark.jpg | MD5 (shark.jpg) = 61aead6a48da0fb25618333590745aa7 |
$ shasum shark.jpg | acfe8421e3ad39cf73f19cef02aa3e692e25d5a2 shark.jpg |
$ crc32 shark.jpg | adc64e03 |
python也能做這個工作,其中md5和sha1需import hashlib
, crc32可以import zlib
#!/usr/bin/env python3
from hashlib import md5, sha1
from zlib import crc32
import sys
def getMd5(filename): #計算md5
mdfive = md5()
with open(filename, 'rb') as f:
mdfive.update(f.read())
return mdfive.hexdigest()
def getSha1(filename): #計算sha1
sha1Obj = sha1()
with open(filename, 'rb') as f:
sha1Obj.update(f.read())
return sha1Obj.hexdigest()
def getCrc32(filename): #計算crc32
with open(filename, 'rb') as f:
return crc32(f.read())
if len(sys.argv) < 2:
print('You must enter the file')
exit(1)
elif len(sys.argv) > 2:
print('Only one file is permitted')
exit(1)
filename = sys.argv[1]
print('{:8} {}'.format('md5:', getMd5(filename)))
print('{:8} {}'.format('sha1:', getSha1(filename)))
print('{:8} {:x}'.format('crc32:', getCrc32(filename)))
$ python3 test.py shark.jpg
,輸出:
md5: 61aead6a48da0fb25618333590745aa7
sha1: acfe8421e3ad39cf73f19cef02aa3e692e25d5a2
crc32: adc64e03
與mac上的計算一致。