How deterministic Are .Net GUIDs?

Question

Yesterday I asked Are GUIDs generated on Windows 2003 safe to use as session IDs? and the answer combined with combined with this article GUIDs are globally unique, but substrin

Answer 1

I suggest you use the System.Security.Cryptography.RandomNumberGenerator. This is designed to produce numbers which can't be reverse engineered. Guid's motivation is to be unique. You could combine both the GUID and secure random number, but a 128 bit secure random number is never going to have a collision on practice.