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AS1 (“Applicability Statement 1”) is an SMIME-based transfer protocol that uses plain old email protocols (such as SMTP and POP3) to transmit files with end-to-end encryption and guaranteed delivery/non-repudiation (when MDNs are in use). End-to-end encryption is accomplished through the use of asymmetric encryption keyed with the public and private[..]


AS2 (“Applicability Statement 2”) is an SMIME-based transfer protocol that uses HTTP/S to transmit files with end-to-end encryption and guaranteed delivery/non-repudiation (when MDNs are in use). There are two main reasons that AS2-based transmission systems are unpopular unless specifically requested by particular partners are complexity and cost. In terms of[..]

AS2 Optional Profiles

AS2 optional profiles (also “optional AS2 profiles”) are features built into the AS2 protocol but not used by every Drummond certified vendor.  However, the Drummond Group does validate seven different optional profiles (nine total) and these are briefly covered below. Certificate Exchange Messaging (CEM) – A standard way of exchanging[..]


AS3 (“Applicability Standard 3”) is an SMIME-based transfer protocol that uses FTP/S to transmit files with end-to-end encryption and guaranteed delivery/non-repudiation (when MDNs are in use). AS3 is an unpopular implementation of the AS2 protocol.  Many vendors successfully sell software that supports AS2 but not AS1 or AS3.  However, AS3’s[..]

Firewall Friendly

A file transfer protocol that is “firewall friendly” typically has most or all of the following attributes: 1) Uses a single port 2) Connects in to a server from the Internet 3) Uses TCP (so session-aware firewalls can inspect it) 4) Can be terminated or proxied by widely available proxy[..]

FTP with PGP

The term “FTP with PGP” describes a workflow that combines the strong end-to-end encryption, integrity and signing of PGP with the FTP transfer protocol.  While FTPS can and often should be used to protect your FTP credentials, the underlying protocol in FTP with PGP workflows is often just plain old[..]

FTPS File Transfer

FTPS File Transfer, FTP Secure or FTP-SSL as it can be referred to, is a secure means of sending data over a network. Often misidentified as SFTP (an independent communications protocol in its own right), FTPS describes the sending of data using basic FTP run over a cryptographic protocol such as SSL (Secure Socket Layers) or TLS (Transport[..]

Internet Protocol Suite

The Internet Protocol Suite is a term used to describe the set of communication protocols, developed individually by the IT community, for sending data over computer networks such as the Internet. TCP (Transmission Control Protocol) and IP (Internet Protocol) were the first two protocols included in the Internet Protocol Suite[..]


IPv6 is the name of the networking protocol which is rapidly replacing the use of IPv4 in wake of widespread IPv4 exhaustion.  IPv6 is defined in 1998’s RFC 2460. IPv6 addresses are written in “colon notation” like “fe80:1343:4143:5642:6356:3452:5343:01a4” rather than the “dot notation” used by IPv4 addresses such as ”[..]


LDAP is a type of external authentication that can provide rich details about authenticated users, including email address, group membership and client certificates. LDAP connection use TCP port 389 but can (and should) be secured with SSL.  When LDAP is secured in this manner, it typically uses TCP port 636[..]


LDAPS refers to LDAP connections secured with SSL, typically over TCP port 636. See “LDAP” for more information.


An MDN (“Message Disposition Notification”) is the method used by the AS1, AS2 and AS3 protocols (the “AS protocols”) to return a strongly authenticated and signed success or failure message back to the senders of the original file.  Technically, MDNs are an optional piece of any AS protocol, but MDNs’[..]

PeSIT protocol

PeSIT is an open file transfer protocol often associated with Axway. It was originally developed before the availability of the Internet as we know it today, to connect mainframe computers via X25. ISDN modems or TCP/IP based WAN’s. Like Sterling Commerce’s proprietary NDM file transfer protocol, PeSIT has now been written[..]


PGP (“Pretty Good Privacy”) is an encryption program that provides cryptographic privacy and authentication for data communication. PGP is used for signing, encrypting, and decrypting texts, e-mails, files, directories, and whole disk partitions and to increase the security of e-mail communications.


RADIUS is an authentication protocol that supports the use of username, password and sometimes one extra credential number such as a hardware token PIN. In file transfer applications, RADIUS sign on information can be collected by web-based, FTP-based or other file transfer prompts and then tried against trusted RADIUS servers.[..]

SFTP File Transfer

SFTP file transfer or the ‘SSH file transfer protocol’ as it is more formally known, is a network communications protocol used for sending data securely over a network. A common misconception associated with SFTP is that it uses FTP run over SSH – this is not the case. SFTP, sometimes[..]


SHA-1 (“Secure Hash Algorithm #1”, also “SHA1”) is the second most common data integrity check standard (a.k.a. “hash”) used throughout the world today.  SHA-1 codes are 160-bit numbers and are usually represented in hexadecimal format (e.g., “de9f2c7f d25e1b3a fad3e85a 0bd17d9b 100db4b3”). SHA-1 is the least secure hash algorithm NIST currently[..]


SMTP is an email protocol used to push messages and attachments from server to server.  Many technologies have been used to secure SMTP over the years, but the best technologies available today use SSL (version 3) or TLS to secure the entire SMTP connection. SMTP typically uses TCP port 25[..]

SSH File Transfer

SSH (Secure Shell) is a network protocol used to establish a secure connection between a client and server. Once a connection has been established, it acts like an encrypted tunnel down which data can be exchanged securely. SSH file transfer is used to maintain the confidentiality and integrity of data[..]


SSL (“Secure Sockets Layer”) was the first widely-deployed technology used to secure TCP sockets.  Its use in HTTPS (HTTP over SSL) allowed the modern age of “ecommerce” to take off on the world wide web and it has also been incorporated into common file transfer protocols such as FTPS (FTP[..]


TLS (“Transport Layer Security”) is the modern version of SSL and is used to secure TCP sockets.  TLS is specified in RFC 2246 (version 1.0), RFC 4346 (version 1.1) and RFC 5246 (version 1.2).  When people talk about connections “secured with SSL”, today TLS is the technology that’s really used[..]

X.509 Certificate

An X.509 certificate is a high-security credential used to encrypt, sign and authenticate transmissions, files and other data.  X.509 certificates secure SSL/TLS channels, authenticate SSL/TLS servers (and sometimes clients), encrypt/sign SMIME, AS1, AS2, AS3 and some “secure zip” payloads, and provide non-repudiation to the AS1, AS2 and AS3 protocols. The[..]