I am just starting to explore Python. I am trying to run an AES algorithm code and I am facing the:
ImportError: No module named Crypto.
How do you solve this?
mx0
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asked Jun 9, 2015 at 16:43
3
answered Jun 9, 2015 at 16:56
5
pip install pycryptodome
It can fix the follows:
ImportError: cannot import name 'Padding' from 'Crypto.Util'
answered Nov 23, 2020 at 17:26
caotcaot
2,87631 silver badges35 bronze badges
Solution:
By installing pycrypto module from your virtualenv
pip install pycrypto
answered Oct 4, 2017 at 14:10
Solved when i installed pycrypto rather then crypto
pip2 install pycrypto
LF00
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answered Mar 23, 2017 at 10:58
0
A common error you may encounter when using Python is modulenotfounderror: no module named ‘Crypto’.
This error occurs when the Python interpreter cannot detect the PyCrypto library in your current environment.
PyCrypto is no longer maintained and should not be used. You should use PyCryptodome, which is a maintained and upgraded fork of PyCrypto. Most applications that depend on PyCrypto will run unmodified
You can install PyCryptodome in Python 3 with python -m pip install pycryptodome
.
This tutorial goes through the exact steps to troubleshoot this error for the Windows, Mac and Linux operating systems.
Table of contents
- ModuleNotFoundError: no module named ‘Crypto’
- What is ModuleNotFoundError?
- What is PyCrypto?
- Always Use a Virtual Environment to Install Packages
- How to Install PyCryptodome on Windows Operating System
- PyCryptodome installation on Windows Using pip
- How to Install PyCryptodome on Mac Operating System using pip
- How to Install PyCryptodome on Linux Operating Systems
- Installing pip for Ubuntu, Debian, and Linux Mint
- Installing pip for CentOS 8 (and newer), Fedora, and Red Hat
- Installing pip for CentOS 6 and 7, and older versions of Red Hat
- Installing pip for Arch Linux and Manjaro
- Installing pip for OpenSUSE
- PyCryptodome installation on Linux with Pip
- How to Install PyCryptodome on Windows Operating System
- Installing PyCryptodome Using Anaconda
- Check PyCryptodome Version
- Summary
ModuleNotFoundError: no module named ‘Crypto’
What is ModuleNotFoundError?
The ModuleNotFoundError occurs when the module you want to use is not present in your Python environment. There are several causes of the modulenotfounderror:
The module’s name is incorrect, in which case you have to check the name of the module you tried to import. Let’s try to import the re module with a double e to see what happens:
import ree
---------------------------------------------------------------------------
ModuleNotFoundError Traceback (most recent call last)
1 import ree
ModuleNotFoundError: No module named 'ree'
To solve this error, ensure the module name is correct. Let’s look at the revised code:
import re
print(re.__version__)
2.2.1
You may want to import a local module file, but the module is not in the same directory. Let’s look at an example package with a script and a local module to import. Let’s look at the following steps to perform from your terminal:
mkdir example_package
cd example_package
mkdir folder_1
cd folder_1
vi module.py
Note that we use Vim to create the module.py file in this example. You can use your preferred file editor, such as Emacs or Atom. In module.py, we will import the re module and define a simple function that prints the re version:
import re
def print_re_version():
print(re.__version__)
Close the module.py, then complete the following commands from your terminal:
cd ../
vi script.py
Inside script.py, we will try to import the module we created.
import module
if __name__ == '__main__':
mod.print_re_version()
Let’s run python script.py from the terminal to see what happens:
Traceback (most recent call last):
File "script.py", line 1, in ≺module≻
import module
ModuleNotFoundError: No module named 'module'
To solve this error, we need to point to the correct path to module.py, which is inside folder_1. Let’s look at the revised code:
import folder_1.module as mod
if __name__ == '__main__':
mod.print_re_version()
When we run python script.py, we will get the following result:
2.2.1
Lastly, you can encounter the modulenotfounderror when you import a module that is not installed in your Python environment.
What is PyCrypto?
PyCrypto is a Python cryptography toolkit and contains a collection of modules for implementing various cryptographic algorithms and protocols including Cipher and Hash.
PyCrypto is no longer maintained and should not be used. You should use PyCryptodome, which is a maintained and upgraded fork of PyCrypto. Most applications that depend on PyCrypto will run unmodified
The simplest way to install PyCryptodome is to use the package manager for Python called pip. The following installation instructions are for the major Python version 3.
Always Use a Virtual Environment to Install Packages
It is always best to install new libraries within a virtual environment. You should not install anything into your global Python interpreter when you develop locally. You may introduce incompatibilities between packages, or you may break your system if you install an incompatible version of a library that your operating system needs. Using a virtual environment helps compartmentalize your projects and their dependencies. Each project will have its environment with everything the code needs to run. Most ImportErrors and ModuleNotFoundErrors occur due to installing a library for one interpreter and using the library with another interpreter. Using a virtual environment avoids this. In Python, you can use virtual environments and conda environments. We will go through how to install PyCryptodome with both.
How to Install PyCryptodome on Windows Operating System
First, you need to download and install Python on your PC. Ensure you select the install launcher for all users and Add Python to PATH checkboxes. The latter ensures the interpreter is in the execution path. Pip is automatically on Windows for Python versions 2.7.9+ and 3.4+.
You can check your Python version with the following command:
python3 --version
You can install pip on Windows by downloading the installation package, opening the command line and launching the installer. You can install pip via the CMD prompt by running the following command.
python get-pip.py
You may need to run the command prompt as administrator. Check whether the installation has been successful by typing.
pip --version
PyCryptodome installation on Windows Using pip
To install PyCryptodome, first, create the virtual environment. The environment can be any name, in this we choose “env”:
virtualenv env
You can activate the environment by typing the command:
envScriptsactivate
You will see “env” in parenthesis next to the command line prompt. You can install PyCryptodome within the environment by running the following command from the command prompt.
python3 -m pip install pycryptodome
We use python -m pip to execute pip using the Python interpreter we specify as Python. Doing this helps avoid ImportError when we try to use a package installed with one version of Python interpreter with a different version. You can use the command which python to determine which Python interpreter you are using.
If you are still getting a No module named Crypto error, check if you have previously installed PyCrypto using pip. You will need to uninstall it and your new install of PyCryptodome as follows:
python3 -m pip uninstall crypto
python3 -m pip uninstall pycryptodome
python3 -m pip install pycryptodome
How to Install PyCryptodome on Mac Operating System using pip
Open a terminal by pressing command (⌘) + Space Bar to open the Spotlight search. Type in terminal and press enter. To get pip, first ensure you have installed Python3:
python3 --version
Python 3.8.8
Download pip by running the following curl command:
curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
The curl command allows you to specify a direct download link. Using the -o option sets the name of the downloaded file.
Install pip by running:
python3 get-pip.py
To install PyCryptodome, first create the virtual environment:
python3 -m venv env
Then activate the environment using:
source env/bin/activate
You will see “env” in parenthesis next to the command line prompt. You can install Django within the environment by running the following command from the command prompt.
python3 -m pip install pycryptodome
How to Install PyCryptodome on Linux Operating Systems
All major Linux distributions have Python installed by default. However, you will need to install pip. You can install pip from the terminal, but the installation instructions depend on the Linux distribution you are using. You will need root privileges to install pip. Open a terminal and use the commands relevant to your Linux distribution to install pip.
Installing pip for Ubuntu, Debian, and Linux Mint
sudo apt install python-pip3
Installing pip for CentOS 8 (and newer), Fedora, and Red Hat
sudo dnf install python-pip3
Installing pip for CentOS 6 and 7, and older versions of Red Hat
sudo yum install epel-release
sudo yum install python-pip3
Installing pip for Arch Linux and Manjaro
sudo pacman -S python-pip
Installing pip for OpenSUSE
sudo zypper python3-pip
PyCryptodome installation on Linux with Pip
To install PyCryptodome, first create the virtual environment:
python3 -m venv env
Then activate the environment using:
source env/bin/activate
You will see “env” in parenthesis next to the command line prompt. You can install PyCryptodome within the environment by running the following command from the command prompt.
Once you have activated your virtual environment, you can install PyCryptodome using:
python3 -m pip install pycryptodome
Installing PyCryptodome Using Anaconda
Anaconda is a distribution of Python and R for scientific computing and data science. You can install Anaconda by going to the installation instructions. Once you have installed Anaconda, you can create a virtual environment and install PyCryptoDome.
To create a conda environment, you can use the following command:
conda create -n crypto python=3.8
You can specify a different Python 3 version if you like. Ideally, choose the latest version of Python. Next, you will activate the project container. You will see “crypto” in parentheses next to the command line prompt.
source activate crypto
Now you’re ready to install PyCryptodome using conda.
Once you have activated your conda environment, you can install PyCryptodome using the following command:
conda install -c conda-forge pycryptodome
Check PyCryptodome Version
Once you have successfully installed PyCryptodome, you can check its version. If you used pip to install PyCryptodome, you can use pip show from your terminal.
python3 -m pip show pycryptodome
Name: pycryptodome
Version: 3.14.1
Summary: Cryptographic library for Python
Second, within your python program, you can import the Crypto and then reference the __version__ attribute:
import Crypto
print(Crypto.__version__)
4.0.2
If you used conda to install PyCryptodome, you could check the version using the following command:
conda list -f pycryptodome
# Name Version Build Channel
pycryptodome 3.14.1 py38hd9741ba_0 conda-forge
Summary
Congratulations on reading to the end of this tutorial. The modulenotfounderror occurs if you misspell the module name, incorrectly point to the module path or do not have the module installed in your Python environment. If you do not have the module installed in your Python environment, you can use pip to install the package. However, you must ensure you have pip installed on your system. You can also install Anaconda on your system and use the conda install command to install PyCryptoDome.
Go to the online courses page on Python to learn more about Python for data science and machine learning.
For further reading on missing modules in Python, go to the article:
- How to Solve Python ModuleNotFoundError: no module named ‘urllib2’.
- How to Solve ModuleNotFoundError: no module named ‘plotly’.
Have fun and happy researching!
Is CTR cipher mode compatible with Java?¶
Yes. When you instantiate your AES cipher in Java:
Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding"); SecretKeySpec keySpec = new SecretKeySpec(new byte[16], "AES"); IvParameterSpec ivSpec = new IvParameterSpec(new byte[16]); cipher.init(Cipher.ENCRYPT_MODE, keySpec, ivSpec);
You are effectively using CTR mode without a fixed nonce and with
a 128-bit big endian counter starting at 0.
The counter will wrap around only after 2¹²⁸ blocks.
You can replicate the same keystream in PyCryptodome with:
ivSpec = b'x00' * 16 ctr = AES.new(keySpec, AES.MODE_CTR, initial_value=ivSpec, nonce=b'')
Are RSASSA-PSS signatures compatible with Java?¶
Yes. For Java, you must consider that by default the
mask is generated by MGF1 with SHA-1 (regardless of how you hash
the message) and the salt is 20 bytes long.
If you want to use another algorithm or another salt length,
you must instantiate a PSSParameterSpec
object, for instance:
Signature ss = Signature.getInstance("SHA256withRSA/PSS"); AlgorithmParameters pss1 = ss.getParameters(); PSSParameterSpec pssParameterSpec = new PSSParameterSpec("SHA-256", "MGF1", new MGF1ParameterSpec("SHA-256"), 32, 0xBC); ss.setParameter(spec1);
Are RSASSA-PSS signatures compatible with OpenSSL?¶
Yes, but one quirk of OpenSSL (and of a few other libraries,
especially if they are wrappers to OpenSSL) is that the salt
length is computed in two possible ways:
Salt length |
Value for |
|
Same as digest size |
|
|
Maximized |
|
|
In PyCryptodome, the salt length matches the digest size by default
(which is what RFC8017 recommends).
However, you can also maximize the salt length with:
key = RSA.import_key(open('privkey.der').read()) h = SHA256.new(message) max_salt_bytes = key.size_in_bytes() - h.digest_size - 2 signature = pss.new(key, salt_bytes=max_salt_bytes).sign(h)
Why do I get the error No module named Crypto
on Windows?¶
Check the directory where Python packages are installed, like:
/path/to/python/Lib/site-packages/
You might find a directory named crypto
, with all the PyCryptodome files in it.
The most likely cause is described here and you can fix the problem with:
pip uninstall crypto pip uninstall pycryptodome pip install pycryptodome
The root cause is that, in the past, you most likely have installed an unrelated but similarly named package called crypto,
which happens to operate under the namespace crypto
.
The Windows filesystem is case-insensitive so crypto
and Crypto
are effectively considered the same thing.
When you subsequently install pycryptodome
, pip
finds that a directory named with the target namespace already exists (under the rules of the underlying filesystem),
and therefore installs all the sub-packages of pycryptodome
in it.
This is probably a reasonable behavior, if it wasn’t that pip does not issue any warning even if it could detect the issue.
Why does strxor
raise TypeError: argument 2 must be bytes, not bytearray
?¶
Most probably you have installed both the pycryptodome
and the old pycrypto
packages.
Run pip uninstall pycrypto
and try again.
The old PyCrypto shipped with a strxor
module written as a native library (.so
or .dll
file).
If you install pycryptodome
, the old native module will still take priority over the new Python extension that comes in the latter.
Why do I get a translation_unit_or_empty undefined
error with pycparser
?¶
Unfortunately,«pycparser« does not work with optimzed (-O
) Python builds,
which strips out the docstrings, causing this error.
This is a known issue and it will not be fixed.
The possible workarounds are:
-
Do not run Python iwth
-O
-
Remove cffi and
cparser
. PyCryptodome will fall back toctypes
for interfacing with the native modules. -
Use an earlier version of
cparser
(2.14)
Вопрос:
Я работаю с pycrypto. Он отлично работает на моем локальном компьютере Windows, но когда я переношу его в свой ящик python, я получаю сообщение об ошибке с импортом модуля:
from Crypto.Cipher import ARC4
ImportError: No module named 'Crypto'
Вывод python3.3 -c "from Crypto.Cipher import ARC4"
Traceback (most recent call last):
File "<string>", line 1, in <module>
ImportError: No module named 'Crypto'
вывод списка pip3 содержит ссылку, включающую в себя pycrypto (2.6.1)
Я знаю, что это работает с Python 2.7.6, но я написал script в 3.3, так что это зависит от некоторых вещей из 3.3
Лучший ответ:
Я предполагаю, что ваш “ящик python” – это удаленный компьютер.
Сначала убедитесь, что pycrypto обновлен (pip3 install --upgrade pycrypto
). Более старые версии могут быть несовместимы с python 3.3
Если это не сработает, попробуйте посмотреть в site-packages (каталог), чтобы убедиться, что функции действительно существуют.
Если ничего из этого не работает, может быть проще (просто предложение) использовать from future import
то, что вам нужно. Таким образом, он совместим с python 2 и 3.
Ответ №1
Как я уже писал в этот ответ:
ВНИМАНИЕ: не используйте pycrypto
больше!
Вместо этого используйте pycryptodome
через pip3 install pycryptodome
.
Но убедитесь, что у вас не установлен pycrypto
, потому что оба пакета устанавливаются в одну и ту же папку Crypto
.
Hello Guys, How are you all? Hope You all Are Fine. Today I am trying to import from Crypto.Cipher import AES But I am facing following error ImportError: No module named Crypto.Cipher in python. So Here I am Explain to you all the possible solutions here.
Without wasting your time, Let’s start This Article to Solve This Error.
Contents
- How ImportError: No module named Crypto.Cipher Error Occurs ?
- How To Solve ImportError: No module named Crypto.Cipher Error ?
- Solution 1: Reinstall pycrypto
- Solution 2: remove crypto and pycrypto
- Solution 3: pycryptodome instead of pycrypto
- Summary
How ImportError: No module named Crypto.Cipher Error Occurs ?
I am trying to import from Crypto.Cipher import AES But I am facing following error.
ImportError: No module named Crypto.Cipher
How To Solve ImportError: No module named Crypto.Cipher Error ?
- How To Solve ImportError: No module named Crypto.Cipher Error ?
To Solve ImportError: No module named Crypto.Cipher Error You just need to reinstall pycrypto so that First of all uninstall pycrypto and then reinstall it. To uinstall pycrypto use this command. pip uninstall pycrypto. Now install pycrypto again with easy install. Use this command. easy_install pycrypto Now your error should be solved. Second solution is Here pycrypto is no longer safe. Use pycryptodome instead, it is a drop-in replacement. So First of all you need to uninstall all versions of
crypto
andpycrypto
first, then installpycryptodome
: pip3 uninstall crypto then pip3 uninstall pycrypto and pip3 install pycryptodome. - ImportError: No module named Crypto.Cipher
To Solve ImportError: No module named Crypto.Cipher Error You just need to reinstall pycrypto so that First of all uninstall pycrypto and then reinstall it. To uinstall pycrypto use this command. pip uninstall pycrypto. Now install pycrypto again with easy install. Use this command. easy_install pycrypto Now your error should be solved. Second solution is Here pycrypto is no longer safe. Use pycryptodome instead, it is a drop-in replacement. So First of all you need to uninstall all versions of
crypto
andpycrypto
first, then installpycryptodome
: pip3 uninstall crypto then pip3 uninstall pycrypto and pip3 install pycryptodome.
Solution 1: Reinstall pycrypto
You just need to reinstall pycrypto so that First of all uninstall pycrypto and then reinstall it. To uinstall pycrypto use this command.
pip uninstall pycrypto
Now install pycrypto again with easy install. Use this command.
easy_install pycrypto
Now your error should be solved.
Solution 2: remove crypto and pycrypto
Just need to remove crypto and pycrypto with this command.
sudo pip uninstall crypto
Then,
sudo pip uninstall pycrypto
and reinstalling pycrypto:
sudo pip install pycrypto
Now, you can import it in your file just like this.
from Crypto.Cipher import AES
Solution 3: pycryptodome instead of pycrypto
Here pycrypto is no longer safe. Use pycryptodome instead, it is a drop-in replacement. So First of all you need to uninstall all versions of crypto
and pycrypto
first, then install pycryptodome
:
pip3 uninstall crypto
pip3 uninstall pycrypto
pip3 install pycryptodome
Summary
It’s all About this issue. Hope all solution helped you a lot. Comment below Your thoughts and your queries. Also, Comment below which solution worked for you?
Also, Read
- ImportError: No module named matplotlib.pyplot