The "Universally unique identifier", or UUID, identifies a consistent format for any unique ID to be used. The UUIDs are 128 bit long. UUID v4 is generated by hashing the namespace UUID and the input string/name.
UUID Version 3 (v3) UniquenessThe UUID v3 is generated by hashing the namespace UUID and input string. UUID v3 makes use of MD5 as the hashing algorithm. The UUID v3 is not randomly generated and is always consistent. So a combination of a particular UUID and input string will always be the same. For example namespace UUID 612c8955-7b39-480a-99cb-ffccc3853143 and input string Hello will always generate the same v3 UUID.