--- layout: "language" page_title: "uuidv5 - Functions - Configuration Language" sidebar_current: "docs-funcs-crypto-uuidv5" description: |- The uuidv5 function generates a uuid v5 string representation of the value in the specified namespace. --- # `uuidv5` Function `uuidv5` generates a _name-based_ UUID, as described in [RFC 4122 section 4.3](https://tools.ietf.org/html/rfc4122#section-4.3), also known as a "version 5" UUID. ``` uuidv5(namespace, name) ``` Unlike the pseudo-random UUIDs generated by [`uuid`](./uuid.html), 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: | Keyword | Namespace ID | Name format | | ------- | ------------ | ----------- | | `"dns"` | `6ba7b810-9dad-11d1-80b4-00c04fd430c8` | A fully-qualified DNS domain name. | | `"url"` | `6ba7b811-9dad-11d1-80b4-00c04fd430c8` | Any valid URL as defined in [RFC 3986](https://tools.ietf.org/html/rfc3986). | | `"oid"` | `6ba7b812-9dad-11d1-80b4-00c04fd430c8` | An [ISO/IEC object identifier](https://oidref.com/) | | `"x500"` | `6ba7b814-9dad-11d1-80b4-00c04fd430c8` | [X.500 Distinguished Name](https://tools.ietf.org/html/rfc1779) | 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.terraform.io") a5008fae-b28c-5ba5-96cd-82b4c53552d6 > uuidv5("url", "https://www.terraform.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.terraform.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`](./uuid.html), which generates pseudorandom UUIDs.