The difference between SFTP and FTS protocols

are encrypted for FTP connections, and the protocols are very similar. One is encrypted with the SSL protocol, and one is encrypted with the SSH protocol. SSL is designed for encryption such as HTTP/SMTP, and SSH is designed to encrypt and establish a transmission channel for TELNET/FTP.
In fact, SSH establishes the transmission channel is for encryption and transmission, and this channel can be used to telnet.
If you just say their function, in layman's words, SSH is like a pipe, SSL is like a package, laying pipes and wrapping will make the data safe, is a process of making the key, and because SSH is a pipe so it is suitable for the secure transmission of FTP.
In fact, it is to be summed up from the principle. Simply put: The SFTP protocol is an independent protocol in SSH that allows data to be transferred using an SFTP server.
And FTPs is the meaning of Ftp-over-ssl, that is, FTP with SSL protocol encryption transmission, not only to use the FTP server and SSL protocol encryption.

from the client side, SSH provides two levels of security validation.

First level (password-based security authentication)

as long as you know your account number and password, you can log on to the remote host. All transmitted data will be encrypted, but there is no guarantee that the server you are connecting to is the one you want to connect to. There may be other servers impersonating a real server, which is an attack by the "middleman".

Second level (key-based security verification)

you need to rely on the key, which means you have to create a pair of keys for yourself and place the public key on the server you need to access. If you are connecting to an SSH server, the client software makes a request to the server requesting security verification with your key. After the server receives the request, look for your public key in your home directory on the server and compare it to the public key you sent. If the two keys are consistent, the server encrypts the "Challenge" (challenge) with a public key and sends it to the client software. After the client software receives a "challenge", it can use your private key to decrypt it and send it to the server.

in this way, you must know the password of your secret key. However, the second level does not require a password to be sent over the network compared to the first level.

The second level not only encrypts all transmitted data, but the "man in the middle" approach is also impossible (because he does not have your private key). However, the entire login process may take up to 10 seconds.

The difference between SFTP and FTS protocols