2023/06/13

That

• uuids are 128 bits long
• in uuid v1, only the first 8 hex digits (32 bits) are randomly generated
• in uuid v4, the entire 128 bits are randomly generated
• uuid v5 derives all 128 bits deterministically from the hash of a seed uuid and some input bytes

See https://www.sohamkamani.com/uuid-versions-explained/