Modulenotfounderror no module named crypto windows

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PyCrypto is no longer maintained and should not be used.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.

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!

Quick Fix: Python raises the ImportError: No module named 'cryptography' when it cannot find the library cryptography. The most frequent source of this error is that you haven’t installed cryptography explicitly with pip install cryptography. Alternatively, you may have different Python versions on your computer, and cryptography is not installed for the particular version you’re using.

Problem Formulation

You’ve just learned about the awesome capabilities of the cryptography library and you want to try it out, so you start your code with the following statement:

import cryptography

This is supposed to import the Pandas library into your (virtual) environment. However, it only throws the following ImportError: No module named cryptography:

>>> import cryptography
Traceback (most recent call last):
  File "<pyshell#6>", line 1, in <module>
    import cryptography
ModuleNotFoundError: No module named 'cryptography'

Solution Idea 1: Install Library cryptography

The most likely reason is that Python doesn’t provide cryptography in its standard library. You need to install it first!

Before being able to import the Pandas module, you need to install it using Python’s package manager pip. Make sure pip is installed on your machine.

To fix this error, you can run the following command in your Windows shell:

$ pip install cryptography

This simple command installs cryptography in your virtual environment on Windows, Linux, and MacOS. It assumes that your pip version is updated. If it isn’t, use the following two commands in your terminal, command line, or shell (there’s no harm in doing it anyways):

$ python -m pip install --upgrade pip
$ pip install pandas

💡 Note: Don’t copy and paste the $ symbol. This is just to illustrate that you run it in your shell/terminal/command line.

Solution Idea 2: Fix the Path

The error might persist even after you have installed the cryptography library. This likely happens because pip is installed but doesn’t reside in the path you can use. Although pip may be installed on your system the script is unable to locate it. Therefore, it is unable to install the library using pip in the correct path.

To fix the problem with the path in Windows follow the steps given next.

Step 1: Open the folder where you installed Python by opening the command prompt and typing where python

Step 2: Once you have opened the Python folder, browse and open the Scripts folder and copy its location. Also verify that the folder contains the pip file.

Step 3: Now open the Scripts directory in the command prompt using the cd command and the location that you copied previously.

Step 4: Now install the library using pip install cryptography command. Here’s an analogous example:

After having followed the above steps, execute our script once again. And you should get the desired output.

Other Solution Ideas

• The ModuleNotFoundError may appear due to relative imports. You can learn everything about relative imports and how to create your own module in this article.
• You may have mixed up Python and pip versions on your machine. In this case, to install cryptography for Python 3, you may want to try python3 -m pip install cryptography or even pip3 install cryptography instead of pip install cryptography
• If you face this issue server-side, you may want to try the command pip install --user cryptography
• If you’re using Ubuntu, you may want to try this command: sudo apt install cryptography
• You can check out our in-depth guide on installing cryptography here.
• You can also check out this article to learn more about possible problems that may lead to an error when importing a library.

Understanding the “import” Statement

import cryptography

In Python, the import statement serves two main purposes:

• Search the module by its name, load it, and initialize it.
• Define a name in the local namespace within the scope of the import statement. This local name is then used to reference the accessed module throughout the code.

What’s the Difference Between ImportError and ModuleNotFoundError?

What’s the difference between ImportError and ModuleNotFoundError?

Python defines an error hierarchy, so some error classes inherit from other error classes. In our case, the ModuleNotFoundError is a subclass of the ImportError class.

You can see this in this screenshot from the docs:

You can also check this relationship using the issubclass() built-in function:

>>> issubclass(ModuleNotFoundError, ImportError)
True

Specifically, Python raises the ModuleNotFoundError if the module (e.g., cryptography) cannot be found. If it can be found, there may be a problem loading the module or some specific files within the module. In those cases, Python would raise an ImportError.

If an import statement cannot import a module, it raises an ImportError. This may occur because of a faulty installation or an invalid path. In Python 3.6 or newer, this will usually raise a ModuleNotFoundError.

Related Videos

The following video shows you how to resolve the ImportError:

The following video shows you how to import a function from another folder—doing it the wrong way often results in the ModuleNotFoundError:

How to Fix “ModuleNotFoundError: No module named ‘cryptography’” in PyCharm

If you create a new Python project in PyCharm and try to import the cryptography library, it’ll raise the following error message:

Traceback (most recent call last):
  File "C:/Users/.../main.py", line 1, in <module>
    import cryptography
ModuleNotFoundError: No module named 'cryptography'

Process finished with exit code 1

The reason is that each PyCharm project, per default, creates a virtual environment in which you can install custom Python modules. But the virtual environment is initially empty—even if you’ve already installed cryptography on your computer!

Here’s a screenshot exemplifying this for the pandas library. It’ll look similar for cryptography.

The fix is simple: Use the PyCharm installation tooltips to install Pandas in your virtual environment—two clicks and you’re good to go!

First, right-click on the pandas text in your editor:

Second, click “Show Context Actions” in your context menu. In the new menu that arises, click “Install Pandas” and wait for PyCharm to finish the installation.

The code will run after your installation completes successfully.

As an alternative, you can also open the Terminal tool at the bottom and type:

$ pip install cryptography

If this doesn’t work, you may want to set the Python interpreter to another version using the following tutorial: https://www.jetbrains.com/help/pycharm/2016.1/configuring-python-interpreter-for-a-project.html

You can also manually install a new library such as cryptography in PyCharm using the following procedure:

• Open File > Settings > Project from the PyCharm menu.
• Select your current project.
• Click the Python Interpreter tab within your project tab.
• Click the small + symbol to add a new library to the project.
• Now type in the library to be installed, in your example Pandas, and click Install Package.
• Wait for the installation to terminate and close all popup windows.

Here’s an analogous example:

Here’s a full guide on how to install a library on PyCharm.

• How to Install a Library on PyCharm

Programmer Humor

❓ Question: Why do programmers always mix up Halloween and Christmas?
❗ Answer: Because Oct 31 equals Dec 25.

(If you didn’t get this, read our articles on the oct() and int() Python built-in functions!)