我同意其他的答案。uuid对于几乎所有的实际用途都是足够安全的，当然对你来说也是如此。

但假设(假设)它们不是。

是否有更好的系统或某种类型的模式来缓解这个问题?

这里有一些方法:

Use a bigger UUID. For instance, instead of a 128 random bits, use 256 or 512 or ... Each bit you add to a type-4 style UUID will reduce the probability of a collision by a half, assuming that you have a reliable source of entropy2. Build a centralized or distributed service that generates UUIDs and records each and every one it has ever issued. Each time it generates a new one, it checks that the UUID has never been issued before. Such a service would be technically straight-forward to implement (I think) if we assumed that the people running the service were absolutely trustworthy, incorruptible, etcetera. Unfortunately, they aren't ... especially when there is the possibility of governments' security organizations interfering. So, this approach is probably impractical, and may be3 impossible in the real world.

1 - If uniqueness of UUIDs determined whether nuclear missiles got launched at your country's capital city, a lot of your fellow citizens would not be convinced by "the probability is extremely low". Hence my "nearly all" qualification. 2 - And here's a philosophical question for you. Is anything ever truly random? How would we know if it wasn't? Is the universe as we know it a simulation? Is there a God who might conceivably "tweak" the laws of physics to alter an outcome? 3 - If anyone knows of any research papers on this problem, please comment.

如果你所说的“有足够的时间”是指100年，你以每秒10亿的速度创造它们，那么是的，100年后你有50%的几率发生碰撞。

UUID类型不止一种，因此“安全程度”取决于您使用的类型(UUID规范称为“版本”)。

Version 1 is the time based plus MAC address UUID. The 128-bits contains 48-bits for the network card's MAC address (which is uniquely assigned by the manufacturer) and a 60-bit clock with a resolution of 100 nanoseconds. That clock wraps in 3603 A.D. so these UUIDs are safe at least until then (unless you need more than 10 million new UUIDs per second or someone clones your network card). I say "at least" because the clock starts at 15 October 1582, so you have about 400 years after the clock wraps before there is even a small possibility of duplications. Version 4 is the random number UUID. There's six fixed bits and the rest of the UUID is 122-bits of randomness. See Wikipedia or other analysis that describe how very unlikely a duplicate is. Version 3 is uses MD5 and Version 5 uses SHA-1 to create those 122-bits, instead of a random or pseudo-random number generator. So in terms of safety it is like Version 4 being a statistical issue (as long as you make sure what the digest algorithm is processing is always unique). Version 2 is similar to Version 1, but with a smaller clock so it is going to wrap around much sooner. But since Version 2 UUIDs are for DCE, you shouldn't be using these.

所以对于所有实际问题，它们都是安全的。如果你不喜欢把它留给概率(例如，你是那种担心地球在你的一生中被一颗大小行星摧毁的人)，只要确保你使用版本1的UUID，并且它保证是唯一的(在你的一生中，除非你计划活到公元3603年以后)。

那么，为什么不是每个人都使用版本1的uuid呢?这是因为版本1的uuid揭示了生成它的机器的MAC地址，并且它们是可以预测的——这两件事可能会对使用这些uuid的应用程序产生安全影响。

我同意其他的答案。uuid对于几乎所有的实际用途都是足够安全的，当然对你来说也是如此。

但假设(假设)它们不是。

是否有更好的系统或某种类型的模式来缓解这个问题?

这里有一些方法:

Use a bigger UUID. For instance, instead of a 128 random bits, use 256 or 512 or ... Each bit you add to a type-4 style UUID will reduce the probability of a collision by a half, assuming that you have a reliable source of entropy2. Build a centralized or distributed service that generates UUIDs and records each and every one it has ever issued. Each time it generates a new one, it checks that the UUID has never been issued before. Such a service would be technically straight-forward to implement (I think) if we assumed that the people running the service were absolutely trustworthy, incorruptible, etcetera. Unfortunately, they aren't ... especially when there is the possibility of governments' security organizations interfering. So, this approach is probably impractical, and may be3 impossible in the real world.

1 - If uniqueness of UUIDs determined whether nuclear missiles got launched at your country's capital city, a lot of your fellow citizens would not be convinced by "the probability is extremely low". Hence my "nearly all" qualification. 2 - And here's a philosophical question for you. Is anything ever truly random? How would we know if it wasn't? Is the universe as we know it a simulation? Is there a God who might conceivably "tweak" the laws of physics to alter an outcome? 3 - If anyone knows of any research papers on this problem, please comment.

我不知道这对您是否重要，但请记住，guid是全局惟一的，但guid的子字符串不是。

摘自维基百科:

因此，任何人都可以创建UUID并使用 用它来表示某物 合理相信 标识符永远不会是 无意中被某人用于 其他东西

它还非常详细地解释了它的安全性。所以回答你的问题:是的，它足够安全。