According to the prompt cryptography is installation problem, I have installed the latest version of alone, but he will unload, return to pack, has been stuck in here you don't succeed

Installing collected packages: cryptography, pyOpenSSL mitmproxy
Found existing installation: cryptography 2.8
Uninstalling cryptography - 2.8:
Successfully uninstalled cryptography - 2.8
Running the setup. Py install for cryptography... The error
ERROR: the Command errored out with the exit status 1:
Command: 'e: \ \ tools \ python python. Exe' - c u - 'import sys, setuptools, tokenize; Sys. Argv [0]='"' "' C: \ \ Users \ \ yj_yj \ \ AppData \ \ Local \ \ Temp \ \ PIP install - c5felb3u \ \ cryptography \ \ setup py '"'" '; __file__='"' "' C: \ \ Users \ \ yj_yj \ \ AppData \ \ Local \ \ Temp \ \ PIP install - c5felb3u \ \ cryptography \ \ setup py '"'" '; F=getattr (tokenize, '"' "' open '"'" 'to open) (__file__); Code=f.r ead (). The replace (' "'" '\ r \ n' "'" ', '"' "' \ n '"'" '); F. lose (); Exec (the compile (code, a __file__, '"' "' exec '"'" ')) 'install - record' C: \ Users \ yj_yj \ AppData \ Local \ Temp \ PIP - record - l1g6yzk2 \ install - record. TXT '- single - version - externally - managed - compile
CWD: C: \ Users \ yj_yj \ AppData \ Local \ Temp \ PIP install - c5felb3u \ cryptography \
Complete the output (109 lines) :
Running the install
Running the build
Running build_py
Creating the build
Creating the build \ lib. Win - amd64-3.8
Creating the build \ lib. Win - amd64-3.8 \ cryptography
Copying the SRC \ cryptography \ exceptions py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography
Copying the SRC \ cryptography \ fernet py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography
Copying the SRC \ cryptography \ utils py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography
Copying the SRC \ cryptography \ __about__ py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography
Copying the SRC \ cryptography \ set py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography
Creating the build \ lib. Win - amd64-3.8 \ cryptography \ hazmat
Copying the SRC \ cryptography \ hazmat \ set py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography \ hazmat
Creating the build \ lib. Win - amd64-3.8 \ cryptography \ x509
Copying the SRC \ cryptography \ x509 \ base py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography \ x509
Copying the SRC \ cryptography \ x509 \ certificate_transparency py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography \ x509
Copying the SRC \ cryptography \ x509 \ extensions py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography \ x509
Copying the SRC \ cryptography \ x509 \ general_name py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography \ x509
Copying the SRC \ cryptography \ x509 \ name py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography \ x509
Copying the SRC \ cryptography \ x509 \ oid py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography \ x509
Copying the SRC \ cryptography \ x509 \ set py - & gt; Build \ lib. Win - amd64-3.8 \ cryptography \ x509