ValueError: Ciphertext length must be equal to key size
ValueError: Ciphertext length must be equal to key size
我知道这个问题被问了很多，但我仍然不太明白如何调试我的代码。我在谷歌上搜索这个问题已经超过 3 天了，但我就是找不到适合我的代码的答案。我想添加带有输入的加密消息，但每次我 运行 我的代码它只给出
Traceback (most recent call last):
File "decryption.py", line 27, in <module>
label=None
File "/opt/anaconda3/lib/python3.7/site-packages/cryptography/hazmat/backends/openssl/rsa.py", line 357, in decrypt
raise ValueError("Ciphertext length must be equal to key size.")
ValueError: Ciphertext length must be equal to key size.
错误。我知道它的标签，但我找不到答案
这是我的解密代码：
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import padding
with open("private_key.pem", "rb") as key_file:
private_key = serialization.load_pem_private_key(
key_file.read(),
password=None,
backend=default_backend()
)
with open("public_key.pem", "rb") as key_file:
public_key = serialization.load_pem_public_key(
key_file.read(),
backend=default_backend()
)
textInput = str(input(">>> "))
encrypted = textInput.encode()
original_message = private_key.decrypt(
encrypted,
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA256()),
algorithm=hashes.SHA256(),
label=None
)
)
original_decoded_message = original_message.decode("utf-8")
print(original_decoded_message)
对于加密：
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import padding
from cryptography.hazmat.primitives import serialization
private_key = rsa.generate_private_key(
public_exponent=65537,
key_size=2048,
backend=default_backend()
)
public_key = private_key.public_key()
pem = private_key.private_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PrivateFormat.PKCS8,
encryption_algorithm=serialization.NoEncryption()
)
with open('private_key.pem', 'wb') as f:
f.write(pem)
pem = public_key.public_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PublicFormat.SubjectPublicKeyInfo
)
with open('public_key.pem', 'wb') as f:
f.write(pem)
raw_message = str(input(">>> "))
message = raw_message.encode("utf-8")
encrypted = public_key.encrypt(
message,
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA256()),
algorithm=hashes.SHA256(),
label=None
)
)
print(encrypted)
我对非对称加密/解密真的很陌生。
你的代码的解密部分的这个小修改使它对我有用：
textInput = str(input(">>> "))
# encrypted = textInput.encode() #this is incorrect!
encrypted = eval(textInput)
这是我得到的：
对于加密部分：
>>> test message
b'>xB)\xf1\xc5I\xd6\xce\xfb\xcf\x83\xe2\xc5\x8f\xcfl\xb9\x0f\xa2\x13\xa5\xe1\x03\xf7p\xb3\x9c\xeb\r\xc1"\xf2\x17\x8b\xea\t\xed\xb2xG\xb7\r\xa9\xf8\x03eBD\xdd9>\xbe\xd1O\xe2\x9f\xbb\xf9\xff5\x96l\xea\x17FI\x8d\x02\x05\xea\x1dpM\xbb\x04J\xfc\x0c\\xfe\x15\x07\xaf \x9e\xc2\xf9M\xa4\x1d$\xc3\x99my\xb6\xc5\xad\x97\xd06\xd2\x08\xd3\xe2\xc8H\xca\xd8\xfd{\xe6\xc6\xa3\x18\xeb\xe6\xcc\xc5\x9a\xc8*\xbb\xc1\x8c\x80,\x1f\r@\x9b\x9d\xc5\x91I\xa8\xc01y\xbc\xa73\xd3\x19;\xef\x8a\xfb\xc2\xc4\x9e\xbe\x8f\xeb\x1d\x12\xbd\xe4<\xa0\xbb\x8d\xef\xee\xa3\x89E\x07"m\x1d\xb0\xf3\xd2:y\xd9\xbd\xef\xdf\xc9\xbb\x1b\xd5\x03\x91\xa4l\x8bS\x9e\x80\x14\x90\x18\xc4\x9e\?\x8eF\x05\xa1H\x9e:\x0c\x96\x8e\xb3E3\x90\xa2\xa1\xd9\x88\xa0<X\x7f\rIP\x00\xbf\xf6\x15\xfb9tW\x17\x9f\xca\x95\xf6|\xd7\x90\xbcp\xe5\xb5,V\x1b\xe9\x90\xf6\x87 v=6'
现在对于解密部分，我使用输出：
>>> b'>xB)\xf1\xc5I\xd6\xce\xfb\xcf\x83\xe2\xc5\x8f\xcfl\xb9\x0f\xa2\x13\xa5\xe1\x03\xf7p\xb3\x9c\xeb\r\xc1"\xf2\x17\x8b\xea\t\xed\xb2xG\xb7\r\xa9\xf8\x03eBD\xdd9>\xbe\xd1O\xe2\x9f\xbb\xf9\xff5\x96l\xea\x17FI\x8d\x02\x05\xea\x1dpM\xbb\x04J\xfc\x0c\\xfe\x15\x07\xaf \x9e\xc2\xf9M\xa4\x1d$\xc3\x99my\xb6\xc5\xad\x97\xd06\xd2\x08\xd3\xe2\xc8H\xca\xd8\xfd{\xe6\xc6\xa3\x18\xeb\xe6\xcc\xc5\x9a\xc8*\xbb\xc1\x8c\x80,\x1f\r@\x9b\x9d\xc5\x91I\xa8\xc01y\xbc\xa73\xd3\x19;\xef\x8a\xfb\xc2\xc4\x9e\xbe\x8f\xeb\x1d\x12\xbd\xe4<\xa0\xbb\x8d\xef\xee\xa3\x89E\x07"m\x1d\xb0\xf3\xd2:y\xd9\xbd\xef\xdf\xc9\xbb\x1b\xd5\x03\x91\xa4l\x8bS\x9e\x80\x14\x90\x18\xc4\x9e\?\x8eF\x05\xa1H\x9e:\x0c\x96\x8e\xb3E3\x90\xa2\xa1\xd9\x88\xa0<X\x7f\rIP\x00\xbf\xf6\x15\xfb9tW\x17\x9f\xca\x95\xf6|\xd7\x90\xbcp\xe5\xb5,V\x1b\xe9\x90\xf6\x87 v=6'
test message
您的原始代码的问题是您正在将字节字符串的 表示 编写为 unicode 字符串（使用 print(encrypted) 时），然后将其编码为解密代码中的字节对象，然后将其传递给解密函数。对该字符串进行编码不会产生原始字节字符串 encrypted.
这个例子说明了问题：
>>> x = bytes(bytearray.fromhex('f3'))
>>> x #A bytes string, similar to encrypt
b'\xf3'
>>> print(x)
b'\xf3'
>>> len(x)
1
>>> str(x) #this is what print(x) writes to stdout
"b'\xf3'"
>>> print(str(x))
b'\xf3'
>>> len(str(x)) #Note that the lengths are different!
7
>>> x == str(x)
False
>>> str(x).encode() #what you were trying to do
b"b'\xf3'"
>>> x == str(x).encode()
False
>>> eval(str(x)) #what gets the desired result
b'\xf3'
>>> x == eval(str(x))
True
问题是那个对象的 print function prints the representation of the object rather than the object itself. Essentially, it does this by getting a printable value of inherently unprintable objects by using __repr__ or __str__ 方法。
这是 __str__ 的文档：
Called by str(object) and the built-in functions format() and print()
to compute the “informal” or nicely printable string representation of
an object. The return value must be a string object.
.
.
The default
implementation defined by the built-in type object calls
object.__repr__().
和__repr__：
Called by the repr() built-in function to compute the “official”
string representation of an object. If at all possible, this should
look like a valid Python expression that could be used to recreate an
object
__repr__ 返回的 "official" 表示允许我在解密代码中使用 eval 函数来解决问题。
TL;DR:
复制 print(encrypted) 的输出会复制 encrypted.__str__() 返回的非正式的、人类可读的值或 encrypted.__repr__() 返回的 "official" 表示，它们都是人类可读的编码，例如 utf-8。它们不能被编码回来（通过使用 utf-8 编码）来创建它们所代表的原始字节字符串。
question from a Whosebug user, facing the same issue. The answer gives a way to actually encode this representation back into a bytes object if you want. It's worth looking into this because eval should be avoided, it is very unsafe 也值得研究。要使该方法起作用，您必须在编码之前从字符串 textInput 中删除前导 b' 和尾随 '。
我的最终建议是通过使用带有 pickle 模块的文件或某种形式的套接字编程，在两个程序之间传递整个对象 encrypted。最好不要使用 print 和 input 在程序之间传递这样的数据，以避免编码问题。
我知道这个问题被问了很多，但我仍然不太明白如何调试我的代码。我在谷歌上搜索这个问题已经超过 3 天了，但我就是找不到适合我的代码的答案。我想添加带有输入的加密消息，但每次我 运行 我的代码它只给出
Traceback (most recent call last):
File "decryption.py", line 27, in <module>
label=None
File "/opt/anaconda3/lib/python3.7/site-packages/cryptography/hazmat/backends/openssl/rsa.py", line 357, in decrypt
raise ValueError("Ciphertext length must be equal to key size.")
ValueError: Ciphertext length must be equal to key size.
错误。我知道它的标签，但我找不到答案 这是我的解密代码：
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import padding
with open("private_key.pem", "rb") as key_file:
private_key = serialization.load_pem_private_key(
key_file.read(),
password=None,
backend=default_backend()
)
with open("public_key.pem", "rb") as key_file:
public_key = serialization.load_pem_public_key(
key_file.read(),
backend=default_backend()
)
textInput = str(input(">>> "))
encrypted = textInput.encode()
original_message = private_key.decrypt(
encrypted,
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA256()),
algorithm=hashes.SHA256(),
label=None
)
)
original_decoded_message = original_message.decode("utf-8")
print(original_decoded_message)
对于加密：
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import padding
from cryptography.hazmat.primitives import serialization
private_key = rsa.generate_private_key(
public_exponent=65537,
key_size=2048,
backend=default_backend()
)
public_key = private_key.public_key()
pem = private_key.private_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PrivateFormat.PKCS8,
encryption_algorithm=serialization.NoEncryption()
)
with open('private_key.pem', 'wb') as f:
f.write(pem)
pem = public_key.public_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PublicFormat.SubjectPublicKeyInfo
)
with open('public_key.pem', 'wb') as f:
f.write(pem)
raw_message = str(input(">>> "))
message = raw_message.encode("utf-8")
encrypted = public_key.encrypt(
message,
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA256()),
algorithm=hashes.SHA256(),
label=None
)
)
print(encrypted)
我对非对称加密/解密真的很陌生。
你的代码的解密部分的这个小修改使它对我有用：
textInput = str(input(">>> "))
# encrypted = textInput.encode() #this is incorrect!
encrypted = eval(textInput)
这是我得到的：
对于加密部分：
>>> test message
b'>xB)\xf1\xc5I\xd6\xce\xfb\xcf\x83\xe2\xc5\x8f\xcfl\xb9\x0f\xa2\x13\xa5\xe1\x03\xf7p\xb3\x9c\xeb\r\xc1"\xf2\x17\x8b\xea\t\xed\xb2xG\xb7\r\xa9\xf8\x03eBD\xdd9>\xbe\xd1O\xe2\x9f\xbb\xf9\xff5\x96l\xea\x17FI\x8d\x02\x05\xea\x1dpM\xbb\x04J\xfc\x0c\\xfe\x15\x07\xaf \x9e\xc2\xf9M\xa4\x1d$\xc3\x99my\xb6\xc5\xad\x97\xd06\xd2\x08\xd3\xe2\xc8H\xca\xd8\xfd{\xe6\xc6\xa3\x18\xeb\xe6\xcc\xc5\x9a\xc8*\xbb\xc1\x8c\x80,\x1f\r@\x9b\x9d\xc5\x91I\xa8\xc01y\xbc\xa73\xd3\x19;\xef\x8a\xfb\xc2\xc4\x9e\xbe\x8f\xeb\x1d\x12\xbd\xe4<\xa0\xbb\x8d\xef\xee\xa3\x89E\x07"m\x1d\xb0\xf3\xd2:y\xd9\xbd\xef\xdf\xc9\xbb\x1b\xd5\x03\x91\xa4l\x8bS\x9e\x80\x14\x90\x18\xc4\x9e\?\x8eF\x05\xa1H\x9e:\x0c\x96\x8e\xb3E3\x90\xa2\xa1\xd9\x88\xa0<X\x7f\rIP\x00\xbf\xf6\x15\xfb9tW\x17\x9f\xca\x95\xf6|\xd7\x90\xbcp\xe5\xb5,V\x1b\xe9\x90\xf6\x87 v=6'
现在对于解密部分，我使用输出：
>>> b'>xB)\xf1\xc5I\xd6\xce\xfb\xcf\x83\xe2\xc5\x8f\xcfl\xb9\x0f\xa2\x13\xa5\xe1\x03\xf7p\xb3\x9c\xeb\r\xc1"\xf2\x17\x8b\xea\t\xed\xb2xG\xb7\r\xa9\xf8\x03eBD\xdd9>\xbe\xd1O\xe2\x9f\xbb\xf9\xff5\x96l\xea\x17FI\x8d\x02\x05\xea\x1dpM\xbb\x04J\xfc\x0c\\xfe\x15\x07\xaf \x9e\xc2\xf9M\xa4\x1d$\xc3\x99my\xb6\xc5\xad\x97\xd06\xd2\x08\xd3\xe2\xc8H\xca\xd8\xfd{\xe6\xc6\xa3\x18\xeb\xe6\xcc\xc5\x9a\xc8*\xbb\xc1\x8c\x80,\x1f\r@\x9b\x9d\xc5\x91I\xa8\xc01y\xbc\xa73\xd3\x19;\xef\x8a\xfb\xc2\xc4\x9e\xbe\x8f\xeb\x1d\x12\xbd\xe4<\xa0\xbb\x8d\xef\xee\xa3\x89E\x07"m\x1d\xb0\xf3\xd2:y\xd9\xbd\xef\xdf\xc9\xbb\x1b\xd5\x03\x91\xa4l\x8bS\x9e\x80\x14\x90\x18\xc4\x9e\?\x8eF\x05\xa1H\x9e:\x0c\x96\x8e\xb3E3\x90\xa2\xa1\xd9\x88\xa0<X\x7f\rIP\x00\xbf\xf6\x15\xfb9tW\x17\x9f\xca\x95\xf6|\xd7\x90\xbcp\xe5\xb5,V\x1b\xe9\x90\xf6\x87 v=6'
test message
您的原始代码的问题是您正在将字节字符串的 表示 编写为 unicode 字符串（使用 print(encrypted) 时），然后将其编码为解密代码中的字节对象，然后将其传递给解密函数。对该字符串进行编码不会产生原始字节字符串 encrypted.
这个例子说明了问题：
>>> x = bytes(bytearray.fromhex('f3'))
>>> x #A bytes string, similar to encrypt
b'\xf3'
>>> print(x)
b'\xf3'
>>> len(x)
1
>>> str(x) #this is what print(x) writes to stdout
"b'\xf3'"
>>> print(str(x))
b'\xf3'
>>> len(str(x)) #Note that the lengths are different!
7
>>> x == str(x)
False
>>> str(x).encode() #what you were trying to do
b"b'\xf3'"
>>> x == str(x).encode()
False
>>> eval(str(x)) #what gets the desired result
b'\xf3'
>>> x == eval(str(x))
True
问题是那个对象的 print function prints the representation of the object rather than the object itself. Essentially, it does this by getting a printable value of inherently unprintable objects by using __repr__ or __str__ 方法。
这是 __str__ 的文档：
Called by
str(object)and the built-in functionsformat()andprint()to compute the “informal” or nicely printable string representation of an object. The return value must be a string object. . . The default implementation defined by the built-in type object callsobject.__repr__().
和__repr__：
Called by the
repr()built-in function to compute the “official” string representation of an object. If at all possible, this should look like a valid Python expression that could be used to recreate an object
__repr__ 返回的 "official" 表示允许我在解密代码中使用 eval 函数来解决问题。
TL;DR:
复制 print(encrypted) 的输出会复制 encrypted.__str__() 返回的非正式的、人类可读的值或 encrypted.__repr__() 返回的 "official" 表示，它们都是人类可读的编码，例如 utf-8。它们不能被编码回来（通过使用 utf-8 编码）来创建它们所代表的原始字节字符串。
eval should be avoided, it is very unsafe 也值得研究。要使该方法起作用，您必须在编码之前从字符串 textInput 中删除前导 b' 和尾随 '。
我的最终建议是通过使用带有 pickle 模块的文件或某种形式的套接字编程，在两个程序之间传递整个对象 encrypted。最好不要使用 print 和 input 在程序之间传递这样的数据，以避免编码问题。