The solution is:

Step 1: Check the information on the Internet. You need to install python's pycrypto library.

(1) To query the installation library, you need to install pip first.

(2) pip installation statement:

Install pip: it is recommended to install Homebrew, and then brew installs python.

Get home-brew: command line execution:/usr/bin/ruby-e "$ (curl-fssl/home brew/install/master/install)"

Command line continues: brew install wget

Check pip again at this time, it has been successfully installed.

Step 2: Install the library with pip

(1) Usage statement: pip3install git+/rncryptor/rncryptor-python.git # egg = rncryptor

(2) Start upgrading the pip version and execute pip3 install pymysql. If there are still errors, you need to execute: PIP3install-Upgrade PIP.

Step 3: install pycrypto library with pip.

(1) Execute the installation statement: pip3install git+/rncryptor/rncryptor-python.git # egg = rncryptor.

(2) According to the prompt log, the library has been installed, and the command line executes: pip3 install Crypto, or prompts the above error, and continues to execute: pip3 install pycrypto or prompts the above error. Directly execute the uninstallation statement: pip3 uninstalls pycrypto, indicating successful uninstallation, and execute again: pip3 installs pycrypto, indicating successful installation, and then restarts pycharm to run the project.