Cautionary note: UUIDs generally do not meet security requirements
littlemaninmyhead.wordpress.com
littlemaninmyhead.wordpress.com
Don't use UUIDs for security purposes.
[1] Dan Boneh and Ramarathnam Venkatesan. Hardness of Computing the Most Significant Bits of Secret Keys in Diffie-Hellman and Related Schemes. In Advances in Cryptology - CRYPTO ’96, 16th Annual International Cryptology Conference, Santa Barbara, California, USA, August 18-22, 1996, Proceedings, pages 129–142, 1996
[2] Nick Howgrave-Graham and Nigel P. Smart. Lattice Attacks on Digital Signature Schemes. Des. Codes Cryptogr., 23(3):283–290, 2001.
[3] Phong Q. Nguyen and Igor E. Shparlinski. The Insecurity of the Digital Signature Algorithm with Partially Known Nonces. J. Cryptology, 15(3):151–176, 2002
[4] Phong Q. Nguyen and Igor E. Shparlinski. The Insecurity of the Elliptic Curve Digital Signature Algorithm with Partially Known Nonces. Des. Codes Cryptogr., 30(2):201–217, 2003