RFC 3749 (rfc3749) - Page 2 of 8
Transport Layer Security Protocol Compression Methods
Alternative Format: Original Text Document
RFC 3749 TLS Compression Methods May 2004
1. Introduction
The Transport Layer Security (TLS) protocol (RFC 2246, [2]) includes
features to negotiate selection of a lossless data compression method
as part of the TLS Handshake Protocol and to then apply the algorithm
associated with the selected method as part of the TLS Record
Protocol. TLS defines one standard compression method,
CompressionMethod.null, which specifies that data exchanged via the
record protocol will not be compressed. While this single
compression method helps ensure that TLS implementations are
interoperable, the lack of additional standard compression methods
has limited the ability of implementers to develop interoperable
implementations that include data compression.
TLS is used extensively to secure client-server connections on the
World Wide Web. While these connections can often be characterized
as short-lived and exchanging relatively small amounts of data, TLS
is also being used in environments where connections can be long-
lived and the amount of data exchanged can extend into thousands or
millions of octets. XML [4], for example, is increasingly being used
as a data representation method on the Internet, and XML tends to be
verbose. Compression within TLS is one way to help reduce the
bandwidth and latency requirements associated with exchanging large
amounts of data while preserving the security services provided by
TLS.
This document describes an additional compression method associated
with a lossless data compression algorithm for use with TLS.
Standardization of the compressed data formats and compression
algorithms associated with this compression method is beyond the
scope of this document.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [1].
2. Compression Methods
TLS [2] includes the following compression method structure in
sections 6.1 and 7.4.1.2 and Appendix sections A.4.1 and A.6:
enum { null(0), (255) } CompressionMethod;
Hollenbeck Standards Track