> For the complete documentation index, see [llms.txt](https://hub.bsvblockchain.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hub.bsvblockchain.org/higher-learning/bsv-academy/hash-functions-crash-course/digital-signatures.md). # Digital Signatures Although hash tables and data structures like Merkle Trees are where hash functions find their greatest use, the most widely recognized use of hash functions is in cryptography. In addition to encryption and key-exchanges, digital signatures make extensive use of hash functions. Like a physical signature, a digital signature associates an identity to a document or message. To ensure the security of digital signatures, well tested algorithms are used to both construct and verify them. In Bitcoin, digital signatures are most commonly used for Pay-to-Public-Key-Hash (P2PKH) transactions – the most common type of Bitcoin transaction template -- where the ownership of funds are transferred from the sending party to the receiving party. The two other common uses of digital signatures in Bitcoin are for signing arbitrary messages and using a Bitcoin address as part of the verification process, and MinerID which is a message included in the first transaction of a block that acts as an authentication mechanism in case another miner (Bitcoin node) tries to act dishonestly while using the ID of a competing miner. With that said, it's helpful to recognize that even though hash functions and cryptographic digital signatures are used in Bitcoin, it is **not** a cryptographic system, and it's actually incorrect to use the term “cryptocurrency” when referring to Bitcoin or a system that follows the Bitcoin architectural design like BSV. This is a really important distinction to be aware of; it is fundamental to how the Bitcoin system operates and how it's secured. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## 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, and the optional `goal` query parameter: ``` GET https://hub.bsvblockchain.org/higher-learning/bsv-academy/hash-functions-crash-course/digital-signatures.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. 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.