CrypTool: http://www.cryptool.org/
Download this software, try to use different methods to encrypt messages, and then try to use the analysis tools to analyze the entropy such as floating frequency, histogram, N-Gram, autocorrelation, and periodicity, etc. Also try to use symmetric key ciphers such as DES and asymmetric ciphers such as RSA, DH, etc.
Click https://www.cryptool.org/en/ link to open resource.