uuidv5 Function

uuidv5 generates a name-based UUID, as described in RFC 4122 section 4.3, also known as a "version 5" UUID.

uuidv5(namespace, name)

Unlike the pseudo-random UUIDs generated by uuid, name-based UUIDs derive from namespace and an name, producing the same UUID value every time if the namespace and name are unchanged.

Name-based UUID namespaces are themselves UUIDs, but for readability this function accepts some keywords as aliases for the namespaces that were assigned by RFC 4122:

To use any other namespace not included in the above table, pass its assigned namespace ID directly in the first argument in the usual UUID string format.

Examples​

Use the namespace keywords where possible, to make the intent more obvious to a future reader:

> uuidv5("dns", "www.placeholderplaceholderplaceholder.io")
a5008fae-b28c-5ba5-96cd-82b4c53552d6

> uuidv5("url", "https://www.placeholderplaceholderplaceholder.io/")
9db6f67c-dd95-5ea0-aa5b-e70e5c5f7cf5

> uuidv5("oid", "1.3.6.1.4")
af9d40a5-7a36-5c07-b23a-851cd99fbfa5

> uuidv5("x500", "CN=Example,C=GB")
84e09961-4aa4-57f8-95b7-03edb1073253

The namespace keywords treated as equivalent to their corresponding namespace UUIDs, and in some special cases it may be more appropriate to use the UUID form:

> uuidv5("6ba7b810-9dad-11d1-80b4-00c04fd430c8", "www.placeholderplaceholderplaceholder.io")
a5008fae-b28c-5ba5-96cd-82b4c53552d6

If you wish to use a namespace defined outside of RFC 4122, using the namespace UUID is required because no corresponding keyword is available:

> uuidv5("743ac3c0-3bf7-4a5b-9e6c-59360447c757", "LIBS:diskfont.library")
ede1a974-df7e-5f17-84b9-76208818b2c8

When using raw UUID namespaces, consider including a comment alongside the expression that indicates which namespace this represents in a human-significant manner, such as by reference to the standard that defined it.

Related Functions​

• uuid, which generates pseudorandom UUIDs.