(The CryptoAPI training tutorial was because the office needed to write a desktop security software on Windows, so I touched CryptoAPI and wrote a tutorial myself for future use. Because of the limited understanding of CAPI at the beginning, it is inevitable that there will be errors and deficiencies in the document, but I will continue to update and maintain this document in the future to cater to the development of MSCAPI, and I hope all friends can support me from beginning to end. CryptoAPI (a usage programming interface) is intended to provide developers with a programming interface for using PKI under Windows. CryptoAPI provides many functions, including encoding, decoding, encryption, decryption, hashing, digital certificates, certificate management, and certificate storage. Regarding encryption and decryption, CryptoAPI provides methods based on both session keys and public/private key pairs.)