A Quadratic Identifier is the peer-to-peer, decentralized solution to a digital object identifier.

[Digital object identifiers (DOIs)](https://en.wikipedia.org/wiki/Digital_object_identifier) are handles that uniquely and persistently identify various objects, particularly academic and scientific information.

The aim of DOIs is to provide a fixed identifier for the life of an object even if the object's location or address (also known as a uniform recourse identifier or URI) changes over time. If systems which reference this object use its DOI, the publisher of the URI can change the address in one location and all references to that URI will reflect the change while the original reference, or DOI, remains constant.

DOIs take the form of a identifier prefix followed by a suffix which are separated by a forward slash, I.e.

```
prefix/suffix
```

The prefix identifies the registrant of the DOI, that is, the entity who registered the identifier. The suffix represents a single object. By incrementing the suffix a single prefix can be used to reference multiple objects. For example, the handle 10/1234 identifies the entity with prefix "10" and an item which the entity would like to provide a reference to is identified using the suffix 1234. Some identifiers prepend additional identifiers which represent the namespace being used. In the case of Quadratic Identifiers, "64" is prepended to the prefix to differentiate it from other services. For example:

```
64.10/1234
```
 	
 where 64 is the Quadratic Identifier namespace, 10 is the registrant's prefix and 1234 is the id of the item.

DOIs are particularly useful for entities with multiple items. For example, a journal can be represented using a unique prefix and the issues of that journal could be identified using an sequentially increasing suffix.

Current handle services which require a single authority to issue DOIs make existing services prone to centralization and a yearly subscription fee negates one of the most important use cases for permanent identifiers; permanence. Quadratic Identifiers solve both these shortcomings by handing of management, payment and resolution of digital identifiers to a smart contract, providing decentralization of architecture and true permanance via the blockchain.

A more in-depth discussion about Quadratic Identifiers and the problem that they solve can be viewed at https://quadratic.systems/.