PyCrypto AES在几行处理输入后突然停止解密

Question

我正在尝试使用两个Python文件加密和解密5-14 MB的文本文件，一个包含加密/解密方法，另一个是这些方法的运行器。

这是类文件：

from Crypto.Cipher import AES
from Crypto import Random
import sys
import codecs
reload(sys)
sys.setdefaultencoding('utf8')
sys.stdout = codecs.getwriter('utf8')(sys.stdout)
class Crypt:
def __init__(self, encrypted, key):
self.message = encrypted
self.key = key
def encrypt(self):
iv = Random.new().read(AES.block_size)
if len(self.message) % AES.block_size != 0:
self.message += " " * (AES.block_size - (len(self.message) % AES.block_size))
lenKey = len(self.key)
if lenKey > 32:
self.key = self.key[:32]
cipher = AES.new(self.key, AES.MODE_CFB, iv)
return iv + cipher.encrypt(self.message)
def decrypt(self):
iv, message = (self.message[:AES.block_size], self.message[AES.block_size:])
if len(message) % AES.block_size != 0:
message += " " * (AES.block_size - (len(message) % AES.block_size))
lenKey = len(self.key)
if lenKey > 32:
self.key = self.key[:32]
cipher = AES.new(self.key, AES.MODE_CFB, iv)
return cipher.decrypt(message).strip()

这是运行器：

import crypt_classes
from Crypto.Hash import SHA256
import sys
reload(sys)
sys.setdefaultencoding('utf8')
h = SHA256.new()
while True:
choice = raw_input("Encrypt [1] or decrypt [2]? ").strip()
if choice != "1" and choice != "2":
print "Invalid choice, please try again."
continue
key = ""
first = ""
confirm = ""
while True:
first = raw_input("Enter passphrase (>= 32 chars): ").strip()
# confirm = raw_input("Confirm passphrase: ").strip()
confirm = first
if first == confirm and len(confirm) >= 32:
h.update(first)
key = h.hexdigest()
break
else:
print "Passphrases did not match or were shorter than 32 characters. Try again."
continue
if choice == "1":
f = open("encrypted.txt", "w")
h = open("source.txt", "r")
message = h.read()
h.close()
encrypter = crypt_classes.Crypt(message, key)
e = encrypter.encrypt()
f.write(e)
f.close()
break
elif choice == "2":
f = open("encrypted.txt", "r")
encrypted = f.read()
f.close()
decrypter = crypt_classes.Crypt(encrypted, key)
w = open("decrypted.txt", "w")
o = decrypter.decrypt()
w.write(o)
w.close()
break

加密工作正常，但是由于文件被解密并且程序表面上完成，文件中只显示几行以及一些杂项 字符，如下所示：

# This data file generated by 23andMe at: Thu May 22 15:47:06 2008
#
# Below is a text version of your data. Fields are TAB-separated
# Each line corresponds to a single SNP.  For each SNP, we provide its identifier 
# (an rsid or an internal id), its lU�

如果需要进一步阐述，请发表评论。

谢谢！

Answer 1

只需使用简单的函数。我认为这里不需要上课。

取十六进制摘要然后截断使有效键长度为 128 而你似乎想要 256。

不要将加密数据写入 UTF8。不要在 CFB 模式下使用填充。

我的尝试(适用于我的系统(;如果您愿意，您可以将加密和解密功能及其导入放在单独的文件(模块(中。

from Crypto.Hash import SHA256
from Crypto.Cipher import AES
from Crypto import Random
import sys
def encrypt_data(data, key):
iv=Random.new().read(AES.block_size)
aes=AES.new(key, AES.MODE_CFB, iv)
return iv+aes.encrypt(data)
def decrypt_data(data, key):
iv = data[:16]
data = data[16:]
aes=AES.new(key, AES.MODE_CFB, iv)
return aes.decrypt(data)
h = SHA256.new()
while True:
choice = raw_input("Encrypt [1] or decrypt [2]? ").strip()
if choice != "1" and choice != "2":
print "Invalid choice, please try again."
continue
key = ""
first = ""
confirm = ""
while True:
first = raw_input("Enter passphrase (>= 32 chars): ").strip()
# confirm = raw_input("Confirm passphrase: ").strip()
confirm = first
if first == confirm and len(confirm) >= 32:
h.update(first)
key = h.digest()
break
else:
print "Passphrases did not match or were shorter than 32 characters. Try again."
continue
if choice == "1":
f = open("encryptedDNA.txt", "w")
h = open("genome_Mikolaj_Habryn_20080522154706.txt", "r")
message = h.read()
h.close()
encmessage = encrypt_data(message, key)
f.write(encmessage)
f.close()
break
elif choice == "2":
f = open("encryptedDNA.txt", "r")
encrypted = f.read()
f.close()
decrypted = decrypt_data(encrypted,key)
w = open("decryptedDNA.txt", "w")
w.write(decrypted)
w.close()
break

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