iv
Table of Contents
EXECUTIVE SUMMARY ......................................................................................................... VI
1 INTRODUCTION ................................................................................................................ 1
1.1 B
ACKGROUND ................................................................................................................ 1
1.2 H
ISTORY OF TLS ............................................................................................................ 1
1.3 S
COPE ............................................................................................................................. 2
1.4 D
OCUMENT CONVENTIONS ............................................................................................ 3
2 TLS OVERVIEW ................................................................................................................. 4
2.1 H
ANDSHAKE PROTOCOL ................................................................................................ 4
2.2 S
HARED SECRET NEGOTIATION ..................................................................................... 5
2.3 C
ONFIDENTIALITY .......................................................................................................... 6
2.4 I
NTEGRITY ...................................................................................................................... 6
2.5 A
UTHENTICATION .......................................................................................................... 7
2.6 A
NTI-REPLAY ................................................................................................................. 7
2.7 K
EY MANAGEMENT ....................................................................................................... 7
3 MINIMUM REQUIREMENTS FOR TLS SERVERS ..................................................... 9
3.1 P
ROTOCOL VERSION SUPPORT ....................................................................................... 9
3.2 S
ERVER KEYS AND CERTIFICATES ................................................................................. 9
3.2.1 Server Certificate Profile ......................................................................................... 10
3.2.2 Obtaining Revocation Status Information for the Client Certificate ....................... 13
3.2.3 Server Public Key Certificate Assurance................................................................. 13
3.3 C
RYPTOGRAPHIC SUPPORT .......................................................................................... 14
3.3.1 Cipher Suites ............................................................................................................ 14
3.3.2 Validated Cryptography .......................................................................................... 19
3.4 TLS
EXTENSION SUPPORT ........................................................................................... 20
3.4.1 Mandatory TLS Extensions ...................................................................................... 20
3.4.2 Conditional TLS Extensions .................................................................................... 21
3.4.3 Discouraged TLS Extensions ................................................................................... 22
3.5 C
LIENT AUTHENTICATION ........................................................................................... 23
3.5.1 Path Validation ........................................................................................................ 23
3.5.2 Trust Anchor Store ................................................................................................... 24
3.5.3 Checking the Client Key Size ................................................................................... 25
3.5.4 Server Hints List ...................................................................................................... 25
3.6 S
ESSION RESUMPTION .................................................................................................. 26
3.7 C
OMPRESSION METHODS ............................................................................................. 26
3.8 O
PERATIONAL CONSIDERATIONS ................................................................................. 26
3.9 S
ERVER RECOMMENDATIONS ...................................................................................... 27
3.9.1 Recommendations for Server Selection ................................................................... 27
3.9.2 Recommendations for Server Installation and Configuration ................................. 27
3.9.3 Recommendations for Server System Administrators .............................................. 31
4 MINIMUM REQUIREMENTS FOR TLS CLIENTS .................................................... 33
4.1 P
ROTOCOL VERSION SUPPORT ..................................................................................... 33
4.2 C
LIENT KEYS AND CERTIFICATES ................................................................................ 33
4.2.1 Client Certificate Profile ......................................................................................... 33
4.2.2 Obtaining Revocation Status Information for the Server Certificate ...................... 35
4.2.3 Client Public Key Certificate Assurance ................................................................. 36
