1. PIP install Python often reports an error:

error: Microsoft Visual C++ 9.0 is required (Unable to find vcvarsall.bat). Get it from http://aka.ms/vcpython27

It seems to be troublesome, too

2. Use the compiled installation package. Download address:

  [pycropt](http://www.voidspace.org.uk/python/modules.shtml#pycrypto)

According to their own version of the corresponding installation can now

However, after installation, it may not be of any use, and the user still reports an error:

No module named Crypto.Cipher

After painstaking search, we finally found the answer on the stack over:
after opening the link, please pull to the last answer

I found the solution. Issue is probably in case sensitivity (on Windows).
Just change the name of the folder:
C:\Python27\Lib\site-packages\crypto
to: C:\Python27\Lib\site-packages\Crypto

The translation is:
rename the crypto folder to crypto