File transfer protocol (FTP) servers with Pretty Good Privacy (PGP) encryption guard data at its two most vulnerable points: at rest and in motion. Before a file leaves the source system, it is compressed and encrypted into a PGP archive using the trading partner’s public key, then uploaded over FTP or its secure versions, such as FTPS or SFTP. The recipient can then use their private key to restore the contents. This process ensures that any data intercepted during transfer or at an insecure endpoint cannot be read.
In managed file transfer (MFT) frameworks, FTP with PGP lets organizations keep functioning FTP scheduling scripts operational for legacy compatibility while still meeting regulatory requirements for file confidentiality, integrity and nonrepudiation. PGP supports automatic key rotation and granular revocation, which simplifies partner onboarding but still requires disciplined key custodianship. The approach also reduces TLS overhead on large payloads because encryption happens once during archiving rather than during every network packet.
PGP encryption
PGP in file transfer environments typically occurs before the actual transfer motion. To set up PGP encryption, administrators will first exchange public keys out of band, script batch encryption and store private keys in HSMs or encrypted keystores. PGP encryption policies will then be enforced for use cases such as encryption on upload or message creation. Upon receipt of a PGP-encrypted file, the client will perform checksum and signature checks to confirm integrity and origin.
Key elements of PGP as it relates to secure file transfer include:
- ASCII armor wraps data in a non-binary encoding
- Compression reduces payload size before transfer
- Key expiration or revocation policies allow prompt authentication and access control
- Signatures can be used to prove integrity and verify sender identity
FTP and secure FTP
Standard FTP should not be used. It transmits commands and payloads unencrypted, so any host on the path can capture credentials or tamper with data. Secure variants, like FTPS and SFTP, wrap the same core functions in encrypted tunnels that prevent data loss in the event of interception.
The differences in secure FTP protocols that matter most in a controlled enterprise transfer environment are:
- FTPS can start encryption on connection (implicit) or after a STARTTLS command (explicit)
- FTPS proves identity with x509 certificates, whereas SFTP uses public-private key pairs
- FTPS runs on TLS, while SFTP relies on secure shell (SSH)
- SFTP maps each user to a chrooted directory, while FTPS inherits file system ACLs
- SFTP uses one port, which simplifies firewall and inspection operations, whereas FTPS opens dynamic data channels
Selecting the right secure protocol and adding PGP will yield a stronger defense without overhauling existing batch schedules.
How PGP is used with FTP
PGP is performed outside of the actual file transfer operation and has little impact on transfer protocols or scripting. Operators encrypt files into .pgp archives on the source server using a partner public key and then push them through FTP applications. Because encryption happens before transmission, payloads remain opaque to network sniffers and man-in-the-middle tools.
The typical file transfer flow with PGP follows these five steps:
- Data partners exchange public keys through a trusted out-of-band channel
- The sender generates a random session key for each file and encrypts the content with AES
- The sender locks the session key with the recipient’s public key and bundles both in the archive
- The sender uploads the archive over FTP, FTPS, SFTP or their choice of accepted protocol
- The recipient decrypts and verifies the signature on the destination with a private key
Benefits of FTP with PGP
Adding PGP to FTP extends protection beyond transport by encrypting every file before it leaves the server. This method lets IT teams strengthen data security in the event of vulnerabilities at file origin or destination points with minimal impact to existing file transfer operations.
Other benefits include:
- Bandwidth savings from built-in compression
- Full end-to-end confidentiality because the ciphertext travels and remains unreadable until the private key unlocks it at the destination
- Layered authentication through optional signatures that reveal tampering during transit or storage
- Rapid partner revocation or onboarding that’s accomplished by updating key rings without affecting transfer scripts
- The addition of a second layer of encryption independent of network ciphers
FTP with PGP tools and software
Deploying FTP with PGP encryption requires two cooperating layers: a cryptographic engine that manages keys and creates .pgp archives and a file transfer service. Many teams pair a command-line OpenPGP utility with scripts in MFT platforms to automate encryption, signing and delivery. When evaluating software, look for native OpenPGP support, CLI access and audit logging so the stack can fit into existing pipelines and security reviews.
Other PGP capabilities to check include:
- Automated key rotation and expiration alerts
- Batch encryption API for large directories
- Detailed logs exportable to your organization’s SIEM for compliance evidence
- FIPS-validated random number sources for key generation
- Support for AES-256 symmetric algorithm inside the PGP container
These features can help streamline secure exchange without overhauling your organization’s current workflow.
FTP with PGP FAQs
FTP PGP combines a file transfer protocol — whether plain FTP, FTPS or SFTP — with Pretty Good Privacy encryption. PGP compresses and encrypts each file on the source system using the recipient’s public key before it moves through existing transfer jobs. Because the archive stays encrypted from origin to destination, it adds a second layer of security in the event of an insecure origin or endpoints.
PGP is not required to secure an SFTP transfer, but it adds an additional level of security at the data origin and endpoints. SFTP encrypts the control and data streams with SSH, so files and credentials are already protected during transfer. PGP addresses a different risk by encrypting the file itself and adding a signature that travels with the payload, guarding copies stored after arrival or passed to other systems.
Whether you add PGP depends on your organization’s policy and workflow. Many teams rely on SFTP alone for internal transfers but adopt PGP when files move across multiple hops, rest in shared storage or when regulations call for object-level encryption and nonrepudiation beyond the network tunnel.
Yes, if you use FTPS, but by default, FTP is not encrypted. Standard FTP defined in RFC 959 sends commands, usernames and file contents in clear text, so anyone with network visibility can read or alter the traffic. It offers no built-in mechanism for confidentiality or integrity and is unsuitable for regulated data or untrusted networks.
Encryption can be introduced in two ways: switch to FTPS, which layers TLS over the original protocol, or move to SFTP, which runs inside an SSH tunnel. Organizations that must keep plain FTP scripts sometimes apply file-level methods such as PGP to encrypt each payload before it crosses the network, but transfers over plain FTP are not recommended.
Yes, OpenPGP tools remain common for signing software packages, encrypting sensitive email and wrapping files for transfer between business partners. Linux distributions publish release keys, cloud backup vendors offer PGP‐based client utilities and MFT platforms integrate command-line PGP agents so archives reach partners already protected.
PGP is a solid solution where policy calls for object-level encryption or signatures that travel with the data. Finance, healthcare and government agencies can use PGP encryption to satisfy requirements for data protection at rest, and PGP encryption can also satisfy cross-border data transfer regulations that require validation that the data has not been accessed during transit.
