}}</ref>[[MasterCard]], [[American Express]] and many leading financial institutions have endorsed SSL for commerce over the Internet.{{Fact|date=December 2007}}▼
| title = Payment Card Industry Data Security Standard Requirements and Security Assessment Procedures, version 1.2
| author = PCI Security Standards Council
| date = October 2008
| page = 19 (requirement 2.3), p. 26 (requirement 4.1)
▲}}</ref>, [[American Express]] and many leading financial institutions have endorsed SSL for commerce over the Internet.{{Fact|date=December 2007}}
SSL operates in modular fashion. It is extensible by design, with support for forward and backward compatibility and negotiation between [[peer-to-peer|peers]].