# Payment ID's *Note:* Long Payment IDs have been removed since release 0.15; it's not possible to use them anymore. More info in the [blog post](https://gethaven.org/2019/06/04/Long-Payment-ID-Deprecation.html) that announced their deprecation. #### The Basics Payment ID is an **arbitrary** and **optional** transaction attachment that consists of 32 bytes (64 hexadecimal characters) or 8 bytes (in the case of integrated addresses). The Payment ID is usually used to identify transactions to merchants and exchanges: Given the intrinsic privacy features built into Haven, where a single public address is usually used for incoming transactions, the Payment ID is especially useful to tie incoming payments with user accounts. #### Compact Payment IDs and Integrated Addresses Since the 0.9 Hydrogen Helix version, Payment IDs can be encrypted and embedded in a payment address. The Payment IDs of this type should be 64-bits and are encrypted with a random one-time key known only to the sender and receiver. #### Creating a Payment ID It is recommended to use the official wallet's `integrated_address` command to automatically generate Integrated Addresses that contain Compact Payment IDs. If you want to use the command line, you can generate Payment IDs as follows: Creating a compact Payment ID for an Integrated Address: `# openssl rand -hex 8` Creating an old-style Payment ID: `# openssl rand -hex 32` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://wiki.havenprotocol.org/overview/payment-ids.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.