SEPP is the Secure Electronic Payment Protocol, an open specification for secure bank card transactions over the Internet developed by IBM, Netscape, GTE, CyberCash and MasterCard [IBM95]. A draft version was released for comment in November 1995. SEPP provides an embodiment of the iKP protocol (see Question 139) intended for HTTP transactions and adapted to bank card payments; SEPP messages are transmitted with MIME (see Question 131) and are based on common ASN.1 syntax including X.509 version 3 certificates (see Question 165) and PKCS #7 "signed data" (see Question 166).
SEPP and STT (see Question 142) were being merged into a joint
Visa-MasterCard protocol called SET, Secure Electronic Transactions,
as of this writing.