SFTP stands for SSH File Transfer Protocol or Secure File Transfer Protocol. It is a network protocol that provides a secure way to transfer files between a client and a server over a network. Unlike traditional FTP (File Transfer Protocol), which is inherently insecure as it sends data, including usernames, passwords, and file contents, in plaintext, SFTP encrypts both commands and data, providing a higher level of security.

Key Features and Characteristics of SFTP:

1. Encrypted Communication:
   • SFTP uses SSH (Secure Shell) to provide encrypted communication between the client and server. All data, including file transfers, commands, and authentication credentials, are encrypted to prevent eavesdropping and unauthorized access.
2. Authentication Methods:
   • SFTP supports various authentication methods, including passwords, public-key cryptography, and host-based authentication. Public-key authentication is widely used in SFTP implementations, offering stronger security compared to password-based authentication.
3. Portability and Compatibility:
   • SFTP is platform-independent and widely supported on different operating systems, including Unix, Linux, macOS, and Windows. It can be integrated into various client applications and server environments.
4. File Transfer Operations:
   • SFTP supports a wide range of file transfer operations, including uploading (put), downloading (get), renaming, deleting, and listing files and directories on the server. These operations are performed securely over the encrypted SSH connection.
5. Remote File Management:
   • SFTP allows users to manage files and directories on remote servers, providing functionality similar to FTP but with enhanced security features. Users can navigate directory structures, create directories, and modify file permissions on the server.
6. Integrity Checks:
   • SFTP includes built-in integrity checks to ensure the integrity of transferred files. It uses cryptographic hashes (e.g., MD5, SHA-1) to verify file integrity during transmission, helping detect data corruption or tampering.
7. Port Numbers:
   • SFTP typically operates on port 22, the default SSH port. This port is used for establishing the SSH connection, authentication, and secure file transfer operations.

Differences Between SFTP and FTP:

1. Security:
   • SFTP encrypts both data and commands using SSH, providing secure transmission over the network. FTP, on the other hand, lacks built-in encryption, making it vulnerable to eavesdropping and data interception.
2. Authentication:
   • SFTP supports stronger authentication mechanisms, including public-key cryptography, whereas traditional FTP relies primarily on username-password authentication, which is less secure.
3. Port Usage:
   • SFTP typically uses port 22 for communication, whereas FTP uses port 21 for command exchange and port 20 for data transfer in active mode or dynamically negotiated ports in passive mode.
4. Firewall Compatibility:
   • SFTP is generally more firewall-friendly than FTP, especially when operating in passive mode. Since SFTP uses a single port (port 22 by default), it’s easier to configure firewalls to allow SFTP traffic compared to FTP, which requires opening multiple ports for data transfer.
5. Complexity:
   • SFTP is considered more complex to configure and manage compared to traditional FTP due to its integration with SSH and additional security features. However, the enhanced security provided by SFTP outweighs the complexity for many organizations, particularly those handling sensitive data.

Overall, SFTP offers a more secure and reliable alternative to FTP for file transfer operations, especially in environments where data security is a top priority. Its encryption, authentication mechanisms, and compatibility make it well-suited for secure file transfers over both local and remote networks.