DDSSEC11 — Specify Authentication Challenge Length

Table 38 – HandshakeRequestMessageToken for the builtin Authentication plugin specifies the challenge as:

A Random Challenge generated by the Participant,
compliant with the recommendations of Section 3.2.1 of
FIPS-196 [46]

This is currently underspecified, as it does not impose restrictions to the challenge length. This can lead to vendor interoperability issues. In order to avoid these issues, the DDS-SECURITY specification should specify alength for DDS-SECURITY 1.0 interoperability. Proposal: 256 bits.

NOTE: In https://tools.ietf.org/html/rfc5246 page 90 that for TLS 1.2, the challenge_length is between 16 and 32 bytes.

Per the resolution of http://issues.omg.org/browse/DDSSEC_-114 it was established that challenges should contain 32 bytes of randomness so the proposal is to specify that the challenge shall be exactly 32 bytes.

Changes in Specification to Specify a Challenge Length and Fixing Typo

Define changes according to DDSSEC11-52.