UUID online generator
What is UUID?
UUID stands for Universally Unique Identifier also known as GUIDs - Globally Unique Identifier. It is 128 bits long, and requires no central registration process.
- Version 1 - generates and returns a RFC4122 v1 (timestamp and MAC based) UUID.
- Version 4 - generates and returns a RFC4122 v4 (random) UUID.
Version 1 of UUID
This version concatenates the MAC address (48-bit) of the computer generating UUID with a timestamp (60-bit). Other versions of UUID (1 and 2) are based on MAC addresses from the network cards of the computer. Because of the usage of the MAC address of the UUID generating node it can be tracked back to the computer that created it. By using this approach the creator of Melissa virus was found. However RFC4122 does allow MAC address to be replaced by random 48-bit node id.
Version 4 of UUID
This version is generated randomly. 4 bits are used to determine the version. 2 or 3 bits are for indicating the variant. So version will have 6 already determined, the rest 122 bits are left for the randomly generated part.