Generate random UUID v4, with batch generation and download support.
Introduction to UUID v4
UUID v4 is a completely randomly generated unique identifier, with 122 of its bits being randomly generated except for fixed format bits. It offers extremely high uniqueness and contains no system or time information.
v4 vs v1
UUID v4 is generated completely randomly, while v1 is based on time and node ID. v4 is more secure and does not leak time or node information, but theoretically has a collision possibility and is slightly slower to generate than v1.
Use cases
UUID v4 is suitable for scenarios requiring privacy and security, such as session IDs, security tokens, and publicly visible identifiers. When high uniqueness is required without leaking generation information, v4 is the preferred choice.
Security advantages
UUID v4 contains no predictable patterns or personal information, making it ideal for security-sensitive applications. Its randomness makes it difficult for attackers to guess or predict identifiers.
Collision probability
Despite being completely random, the collision probability of UUID v4 is extremely low. When generating 103 trillion UUID v4s, the collision probability is about 50% (birthday paradox). In practical applications, this risk is usually negligible.
Performance considerations
UUID v4 generation relies on a random number generator, making it slightly slower than v1, but the difference is insignificant in most applications. Performance differences only need consideration when generating a large number of identifiers at high frequency.