FTP vs FTPS vs SFTP

File Transfer Protocol (FTP) :

FTP (File Transfer Protocol) is the traditional way to transfer files from clients to servers. Invented in the 70s, FTP is a simple way to move files between computers via TCP/IP — the framework that connects network devices online. Here's how FTP usually works:

• You upload files to the FTP server.
• You send these files via TCP/IP to the FTP host.
• The recipient receives and downloads the files.

FTP handles three data representations (8-binary data, ASCII 7-Bit, and EBCDIC 8-Bit) and moves files via one of three transmission modes (block, stream, and compressed.) 

FTP Pros

• It's quick and simple, and people have used it for 40 years.
• It transfers multiple directories at the same time. 

FTP Cons

• As you've probably guessed, FTP is not the safest way to send files:
• There's no encryption involved.
• FTP uses two data channels, which increases the risk of hackers stealing your files.

File Transfer Protocol Secure (FTPS) :

FTPS is known as FTP SSL which refers to File Transfer Protocol (FTP) over Secure Sockets Layer (SSL) which is more secure from FTP. FTPS also called as File Transfer Protocol Secure. It refers to basic FTP with security which protects data from any attack by encrypting it so that no one can be able to make use of any information in between transmission at both the ends. It implements AES algorithm, Triple DES algorithm, and many other algorithms to encrypt data.

• FTPS refers to File Transfer Protocol with SSL.
• It is also known as File Transfer Protocol (FTP) over Secure Sockets Layer (SSL).
• File Transfer Protocol Secure in short known as FTPS.
• Key based authentication is not supported
• In this certificates are supported.
• It uses multiport numbers. Each time a file transfer request is made another port number needs to be opened for the data channel.
• It is most commonly used due to its ubiquitous legacy.
• Authentication is performed via x.509 certificates.
• It has separate connection for command and file data.

Pros of FTPS :

• It is widely known and used
• Communication is readable and understandable by human
• It is encrypted
• Easy to implement
• Provides services for server to server file transfers based on SSL/TLS
• It has built in support in .NET framework

Cons of FTPS :

• It does not have a consistent directory listing format Not all FTP servers support SSL/TLS
• It can not perform file system operations
• It requires a secondary data channel
• Older FTP servers do not support SSL
• It doesn’t have a standard way for getting & changing file or directory attributes

Secure File Transfer Protocol (SFTP) :

SFTP known is known as SSH FTP which refers to File Transfer Protocol (FTP) over Secure Shell (SSH) which encrypts both commands and data while in transmission. SFTP also called as Secure File Transfer Protocol. It works as an extension to SSH. It encrypts files and data then sends them over a secure shell data stream. This protocol allows to remotely connect to other systems and executing commands from the command line. Like FTPS it also implements AES algorithm, Triple DES algorithm, and many other algorithms to encrypt data.

• SFTP refers to SSH File Transfer Protocol.
• It is also known as File Transfer Protocol (FTP) over Secure Shell (SSH).
• Secure File Transfer Protocol in short known as SFTP.
• SSH keys can be used to authenticate SFTP connections.
• In this certificates are not supported.
• SFTP needs only a single port number for all SFTP communications and makes it easy to secure and provide greater protection.
• But now a days it is more common in recent devices and software.
• Authentication is performed via SSH keys.
• It has no separate connection for command and file data.

Pros of SFTP :

• It has a good standard background which defines most aspects of operations
• It is easy to use behind
• firewall as it uses one port
• Connection is constantly protected/secured
• Directory listing is consistent/uniform
• It has only one connection and no need for a Data connection

Cons of SFTP :

• The interaction is binary and can not be logged as- is for human reading
• It is difficult to manage and validate SSH keys
• No server to server copy
• There is no built in SSH/SFTP support in .NET frameworks
• Probability of compatibility problems
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