How Does SFTP Work?

Secure File Transfer Protocol (SFTP) is a secure network protocol designed for transferring large files and sensitive data over the internet. It improves upon the traditional File Transfer Protocol (FTP) by embedding SSH encryption (Secure Shell) into the file transfer process. This ensures data privacy, integrity, and security during transmission between client and server endpoints.

Unlike FTP, which transmits data in cleartext, SFTP encrypts both the authentication credentials and file content, protecting data from unauthorized access, interception, and tampering.

SFTP Essentials: Why It Matters

SFTP is the secure evolution of FTP, created to address rising concerns around data breaches and cyberattacks. Originally developed by Tatu Ylönen in 1997, SFTP became an open standard supported by the IETF. While FTP served as a file-sharing standard since the 1970s, it lacked the encryption needed to meet modern data security and compliance standards such as HIPAA, PCI-DSS, GDPR, and CCPA.

FTP’s transmission in unencrypted plain text leaves files vulnerable to interception. In contrast, SFTP uses SSH tunneling to secure the connection and encrypt all data in transit.

How SFTP Works

To understand how SFTP functions, it’s helpful to compare it with FTP and explore the role of SSH in the secure transmission process.

How FTP Works

FTP (File Transfer Protocol) transfers files between a client and an FTP server using two separate channels:

• Control Channel: Maintains the connection and sends commands.
• Data Channel: Handles actual file transfers.

The key limitation? FTP transmits all data—including credentials—in unencrypted plain text. This exposes sensitive information and may violate data security regulations.

How SSH Works

SSH (Secure Shell) is a cryptographic protocol that secures network services by encrypting communication between endpoints. SSH ensures both confidentiality and integrity, and it’s the foundational layer that makes SFTP a secure file transfer solution.

How SFTP Works

SFTP operates over a single, encrypted SSH connection, simplifying the transfer process and reducing the attack surface. Key benefits include:

• End-to-end encryption for credentials and file data
• Fewer ports needed, improving firewall compatibility
• Stronger compliance with data protection regulations
• Improved security posture for businesses transferring confidential information

SFTP vs Other File Transfer Protocols

While SFTP and FTP are widely used for file transfers, both face limitations when it comes to speed, scalability, and long-distance performance. As businesses grow and move to cloud-first architectures, the need for faster large file transfer solutions becomes critical.

The Limitations of SFTP and FTP

• Slow transfer speeds over long distances
• High latency in global file collaboration
• Not built for modern cloud or hybrid environments

To overcome these challenges, companies are turning to next-gen solutions like IBM Aspera, which was built specifically for high-speed data transfer.

IBM Aspera FASP: The Modern Alternative to SFTP

IBM Aspera introduces a proprietary protocol called FASP (Fast, Adaptive, and Secure Protocol) that redefines what’s possible in large-scale data transfers.

Key Benefits of Aspera FASP:

• 100x faster than SFTP
• Optimized for large file transfer across global distances
• Maintains end-to-end encryption and compliance
• Eliminates traditional bottlenecks caused by TCP-based protocols

With Aspera, businesses can transfer terabytes of data in hours—not days—allowing for seamless collaboration across continents.

Use the Aspera File Transfer Calculator to compare Aspera’s transfer speeds with your current system and discover how your business can accelerate productivity while ensuring data security.

Next Steps: Secure and Scalable File Transfer with PacGenesis

Looking to upgrade from traditional SFTP to a more scalable, secure file transfer solution? Partner with PacGenesis, an IBM Gold Business Partner with over a decade of experience in enterprise file transfer and cybersecurity.

We help organizations implement file transfer solutions that meet both speed and security requirements, from SFTP setups to advanced Aspera deployments.

Contact us today to learn how to:

• Accelerate global file collaboration with IBM Aspera
• Secure your file transfers with SFTP and SSH
• Ensure compliance with HIPAA, PCI-DSS, GDPR, and CCPA

To learn more about PacGenesis, follow @PacGenesis on Facebook, Twitter, and LinkedIn, or go to www.pacgenesis.com. 

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