Transport Layer Security (TLS) can be used to provide data integrity and confidentiality protection. OpenLDAP supports negotiation of TLS (SSL) via both StartTLS and ldaps://. See the Using TLS chapter for more information. StartTLS is the standard track mechanism.
A number of Simple Authentication and Security Layer (SASL) mechanisms, such as DIGEST-MD5 and GSSAPI, also provide data integrity and confidentiality protection. See the Using SASL chapter for more information.
The server uses Security Strength Factors (SSF) to indicate the relative strength of protection. A SSF of zero (0) indicates no protections are in place. A SSF of one (1) indicates integrity protection are in place. A SSF greater than one (>1) roughly correlates to the effective encryption key length. For example, DES is 56, 3DES is 112, and AES 128, 192, or 256.
A number of administrative controls rely on SSFs associated with TLS and SASL protection in place on an LDAP session.
security controls disallow operations when appropriate protections are not in place. For example:
security ssf=1 update_ssf=112
requires integrity protection for all operations and encryption protection, 3DES equivalent, for update operations (e.g. add, delete, modify, etc.). See slapd.conf(5) for details.
For fine-grained control, SSFs may be used in access controls. See The access Configuration Directive section of the The slapd Configuration File for more information.