How do I install PyCrypto on Windows?

This probably isn’t the optimal solution but you might download and install the free Visual C++ Express package from MS. This will give you the C++ compiler you need to compile the PyCrypto code.

In general

vcvarsall.bat is part of the Visual C++ compiler, you need that to install what you are trying to install. Don’t even try to deal with MingGW if your Python was compiled with Visual Studio toolchain and vice versa. Even the version of the Microsoft tool chain is important. Python compiled with VS 2008 won’t work with extensions compiled with VS 2010!

You have to compile PyCrypto with the same compiler that the version of Python was compiled with. Google for “Unable to find vcvarsall.bat” because that is the root of your problem, it is a very common problem with compiling Python extensions on Windows.

There is a lot of information and a lot to read to get this right on whatever system you are on with this link.

Beware using Visual Studio 2010 or not using Visual Studio 2008

As far as I know the following is still true. This was posted in the link above in June, 2010 referring to trying to build extensions with VS 2010 Express against the Python installers available on python.org.

Be careful if you do this. Python 2.6 and 2.7 from python.org are
built with Visual Studio 2008 compilers. You will need to link with
the same CRT (msvcr90.dll) as Python.

Visual Studio 2010 Express links with the wrong CRT version:
msvcr100.dll.

If you do this, you must also re-build Python with Visual Studio 2010
Express. You cannot use the standard Python binary installer for
Windows. Nor can you use any C/C++ extensions built with a different
compiler than Visual Studio 2010 (Express).

Opinion: This is one reason I abandoned Windows for all serious development work for OSX!

It’s possible to build PyCrypto using the Windows 7 SDK toolkits. There are two versions of the Windows 7 SDK. The original version (for .Net 3.5) includes the VS 2008 command-line compilers. Both 32- and 64-bit compilers can be installed.

The first step is to compile mpir to provide fast arithmetic. I’ve documented the process I use in the gmpy library. Detailed instructions for building mpir using the SDK compiler can be found at sdk_build

The key steps to use the SDK compilers from a DOS prompt are:

1) Run either vcvars32.bat or vcvars64.bat as appropriate.

2) At the prompt, execute “set MSSdk=1”

3) At the prompt, execute “set DISTUTILS_USE_SDK=1”

This should allow “python setup.py install” to succeed assuming there are no other issues with the C code. But I vaaguely remember that I had to edit a couple of PyCrypto files to enable mpir and to find the mpir libraries but I don’t have my Windows system up at the moment. It will be a couple of days before I’ll have time to recreate the steps. If you haven’t reported success by then, I’ll post the PyCrypto steps. The steps will assume you were able to compile mpir.

I hope this helps.

For VS2010:

SET VS90COMNTOOLS=%VS100COMNTOOLS%

For VS2012:

SET VS90COMNTOOLS=%VS110COMNTOOLS%

then Call:

pip install pyCrypto 

I have managed to get pycrypto to compile by using MinGW32 and MSYS. This presumes that you have pip or easy_install installed.

Here’s how I did it:

1) Install MinGW32. For the sake of this explanation, let’s assume it’s installed in C:MinGW. When using the installer, which I recommend, select the C++ compiler. MSYS should install with MinGW

2) Add c:mingwbin,c:mingwmingw32bin,C:MinGWmsys1.0, c:mingwmsys1.0bin and c:mingwmsys1.0sbin to your %PATH%. If you aren’t familiar, this article is very helpful.

3) From the search bar, run msys and the MSYS terminal will open. For those familiar with Cygwin, it works in a similar fashion.

4) From within the MSYS terminal pip install pycrypto should run without error after this.

So I install MinGW and tack that on the install line as the compiler
of choice. But then I get the error “RuntimeError: chmod error”.

This error "RuntimeError: chmod error" occurs because the install script didn’t find the chmod command.

How in the world do I get around this?

Solution

You only need to add the MSYS binaries to the PATH and re-run the install script.

(N.B: Note that MinGW comes with MSYS so )

Example

For example, if we are in folder C:<..>pycrypto-2.6.1distpycrypto-2.6.1>

C:.....>set PATH=C:MinGWmsys1.0bin;%PATH%
C:.....>python setup.py install

Optional: you might need to clean before you re-run the script:

`C:<..>pycrypto-2.6.1distpycrypto-2.6.1> python setup.py clean`

Microsoft has recently recently released a standalone, dedicated Microsoft Visual C++ Compiler for Python 2.7. If you’re using Python 2.7, simply install that compiler and Setuptools 6.0 or later, and most packages with C extensions will now compile readily.

After years and years, python finally agreed for a binary disribution called wheel which allows to install even binary extensions on Windows without having a compiler with simple pip install packagename. There is a list of popular packages with their status. Pycrypto is not there yet, but lxml, PySide and Scrapy for example.

Edited Nov 2015: pip uninstall pycrypto & pip install pycryptodome. It is a pycrypto fork with new features and it supports wheel. It replaces pycrypto, so existing code will continue to work (see https://pycryptodome.readthedocs.org/en/latest/src/examples.html)

For Windows 7:

To install Pycrypto in Windows,

Try this in Command Prompt,

Set path=C:Python27Scripts (i.e path where easy_install is located)

Then execute the following,

easy_install pycrypto

For Ubuntu:

Try this,

Download Pycrypto from “https://pypi.python.org/pypi/pycrypto“

Then change your current path to downloaded path using your terminal and user should be root:

Eg: root@xyz-virtual-machine:~/pycrypto-2.6.1#

Then execute the following using the terminal:

python setup.py install

It’s worked for me. Hope works for all..

So I install MinGW and tack that on the install line as the compiler of choice. But then I get the error “RuntimeError: chmod error”.

You need to install msys package under MinGW

and add following entries in your PATH env variable.

• C:MinGWbin
• C:MinGWmsys1.0bin [This is where you will find chmod executable]

Then run your command from normal windows command prompt.

For those of you looking for python 3.4 I found a git repo with an installer that just works. Here are the direct links for x64 and x32

PyCryptodome is an almost-compatible fork of PyCrypto with Windows wheels available on pypi.

You can install it with a simple:

pip install pycryptodome

The website includes instructions to build it from sources with the Microsoft compilers too.

1. Go to “Microsoft Visual C++ Compiler for Python 2.7“ and continue based on “System Requirements” (this is what I did to put below steps together).

2. Install setuptools (setuptools 6.0 or later is required for Python to automatically detect this compiler package)
   either by: pip install setuptools
   or download “Setuptools bootstrapping installer” source from, save this file somwhere on your filestystem as “ez_python.py” and install with: python ez_python.py

3. Install wheel (wheel is recommended for producing pre-built binary packages). You can install it with: pip install wheel

4. Open Windows elevated Command Prompt cmd.exe (with “Run as administrator”) to install “Microsoft Visual C++ Compiler for Python 2.7” for all users. You can use following command to do so: msiexec /i C:usersjozkodownloadVCForPython27.msi ALLUSERS=1 just use your own path to file: msiexec /i <path to MSI> ALLUSERS=1

5. Now you should be able to install pycrypto with: pip install pycrypto

Try just using:

pip install pycryptodome

or:

pip install pycryptodomex

Source: https://pypi.python.org/pypi/pycryptodome

My answer might not be related to problem mention here, but I had same problem with Python 3.4 where Crypto.Cipher wasn’t a valid import. So I tried installing PyCrypto and went into problems.

After some research I found with 3.4 you should use pycryptodome.

I install pycryptodome using pycharm and I was good.

from Crypto.Cipher import AES

Step 1: Install Visual C++ 2010 Express from
here.

(Do not install Microsoft Visual Studio 2010 Service Pack 1 )

Step 2: Remove all the Microsoft Visual C++ 2010 Redistributable packages from Control PanelPrograms and Features. If you don’t do those then the install is going to fail with an obscure “Fatal error during installation” error.

Step 3: Install offline version of Windows SDK for Visual Studio 2010 (v7.1) from here.
This is required for 64bit extensions. Windows has builtin mounting for ISOs like Pismo.

Step 4: You need to install the ISO file with Pismo File Mount Audit Package. Download Pismo from here

Step 5: Right click the downloaded ISO file and choose mount with Pismo. Thereafter, install the SetupSDKSetup.exe instead of setup.exe.

Step 6a: Create a vcvars64.bat file in C:Program Files (x86)Microsoft Visual Studio 10.0VCbinamd64 by changing directory to C:Program Files (x86)Microsoft Visual Studio versionVC on the command prompt.
Type command on the command prompt:
cd C:Program Files (x86)Microsoft Visual Studio versionVCr

Step 6b:
To configure this Command Prompt window for 64-bit command-line builds that target x86 platforms, at the command prompt, enter:
vcvarsall x86 Click here for more options.

Step 7: At the command prompt, install the PyCrypto by typing:
C:Python3X>pip install -U your_wh_file

I had Pycharm for python.

1. Go to pycharm -> file -> setting -> project interpreter

2. Click on +

3. Search for "pycrypto" and install the package

Note: If you don’t have “Microsoft Visual C++ Compiler for Python 2.7” installed then it will prompt for installation, once installation finished try the above steps it should work fine.

If you are on Windows and struggling with installing Pycrypcto just use the:
pip install pycryptodome.
It works like a miracle and it will make your life much easier than trying to do a lot of configurations and tweaks.

I tried several suggestions here, including pycryptodome and none of them worked for me. I ended up using the method suggested in this answer in SuperUser and it succeeded to install pycrypto.
OS: Windows 10
Python version: 3.10.7