What is PeSIT?
PeSIT, short for Protocol d'Echanges pour un Systeme Interbancaire de Telecompensation (Protocol for data Exchange within the French Systems for Interbank Tele-clearance), is an end-to-end open-source file transfer protocol that was developed in 1986 by the French Interbank Teleclearing Systems Economic Interest Grouping (GSIT).
The PeSIT protocol was designed from the ground up with a focus on control and security, with unique features among the various file transfer protocols. It was initially a very popular way to transfer files and was considered secure for the industries that used it before options like FTPS and SFTP came along.
From A to Z: GoAnywhere Glossary
How Does PeSIT Operate?
PeSIT is thought of as a unique, but complex protocol compared to the other top methods of transferring files. With PeSIT, configuration must be agreed upon and accurate between both the caller and server. Once the configuration is on sync, messages are then exchanged asymmetrically between both parties.
The session originator, or the caller, is the partner who determines what work needs to be done during the session and is the closest contact with the user (the server). The server executes the work proposed by the caller and supplies a report on the work carried out.
The PeSIT protocol only allows one file to be transferred at a time during a particular session, but several files can be transferred simultaneously if several sessions are open. The work carried out during a PeSIT session can be structured dynamically into a series of commands within each other which must be opened in a hierarchical order and closed in the reverse order. If the session is interrupted or discontinued prematurely by a user, all of the commands which are still active are considered to have been implicitly closed.
PeSIT’s file data flow control smoothly shares CPU and bandwidth resources among file transfers during heavy workloads. Transfer processes are tracked across the network using unique identifiers and transfers can be triggered and executed with differently assigned priority levels. It’s also important to know that neither the file name nor its location on the host or destination file system is ever shared across the network for security reasons. However, there are parts of the protocol that let you provide a “file name” to the receiver of the file.
The PeSIT protocol has a stable interface regardless of the different communication layers used and describes the parameters needed to implement the security mechanisms and the manner they are exchanged. However, the total implementation (algorithms, key and certificate management) are not part of the protocol.
PeSIT’s File System Agnostic Nature
PeSIT is a file system agnostic protocol, as in it doesn’t have a concept of files or directories. Existing file systems vary considerably in their implementations of file format and file storage. Thus, it’s necessary to create a common model of the file for use by any protocol working in a heterogeneous network environment. This model is called the "virtual file.” A virtual file enables the inner workings of a file storage system specific to a particular operating system to be made transparent to the protocol by means of conversion functions which map the local file description into a standardized file description and vice-versa.
In summary, PeSIT isn't opinionated on how your data is stored. It doesn't have a concept of directories or navigating a file system structure. It just needs to know how the data is encoded for what its reading/writing, how big of chunks to send over the wire, and how the caller is to identify the virtual file (name).
How Does the Protocol Function?
The PeSIT protocol provides the following service functions:
- Writing (of a distant) file: This function allows a user of PeSIT to transfer the contents of a file to another user of PeSIT.
- Reading (of a distant) file: This function allows a user of PeSIT to request that another user of PeSIT transfer the contents of a file to them.
- Checkpointing during a transfer: This function allows the sender to set milestones, also known as checkpoints, which are numbered sequentially during the transfer. The receiver can then acknowledge the checkpoints, which signifies the data has been received and saved correctly.
- Transfer security: This function allows users of PeSIT to implement the following security mechanisms:
- Reciprocal authentication
- Confidentiality of the transmitted data
- Integrity of the transmitted data
- Reciprocal non-repudiation
- Data compression: This function allows users to implement the data compression mechanisms of PeSIT, thus reducing the quantity of transmitted data.
- Error control: By using a polynomial error detection algorithm applied to each PeSIT protocol message, this function allows the detection of messages which have been deteriorated by an unreliable transmission medium.
Should You Use or Avoid the PeSIT Protocol?
For over 30 years, thousands of companies have relied on PeSIT to ensure the transfer of files within demanding corporate environments, but in actuality it has not been considered a popular protocol since the mid 90’s.
As of today, PeSIT isn’t used much in North America and is primarily used to meet European banking standards and transfer communications to and from banks in Europe. However, the use of PeSIT is not limited to just these areas and may indeed be used in a variety of environments.
Overall, the PeSIT protocol isn’t very well known and not many are considered experts in it. It’s also not supported by many providers as it can limit the ability to select software providers.
Unless PeSIT is specifically mandated by an industry rule or statute, or if a trading partner requires the usage of it, new deployments typically look to more modernized transfer protocols such as FTPS or SFTP.
Need to Use the PeSIT Protocol? See Our Options!
If your organization is required to use the PeSIT protocol or you need to do secure electronic data exchange, GoAnywhere Managed File Transfer (MFT) offers several specialized options to choose from – Express, Premium, and Enterprise. With these you can gain access to the PeSIT Client, PeSIT Server, and so much more.
Request a quote to find out how GoAnywhere MFT can take care of your PeSIT file transfers and fit in your organization's IT and cybersecurity budget.
