> 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/wiki/cryptography-and-keys/cryptography/digital-signatures-in-bitcoin.md).

# Digital Signatures in Bitcoin

The Bitcoin whitepaper describes an electronic coin as a chain of digital signatures. These digital signatures confer practical control, and in most cases, ownership over the coins held in any given script, and can be used as a record of custodial control to trace transfers of control back through the history of the ledger.

![Electronic coins are defined as a chain of digital signatures](/files/WC4UQv5JBiA8JvP586Xb)

A digital signature isn't merely a message signed using a given keypair, but is a link to an identity. The European Union legislation on digital signatures states that signatures correspond to “data in electronic form which are attached to or logically associated with other electronic data and which serve as a method of authentication”. Bitcoin script allows users to lock/unlock their bitcoin in different ways.

1. Elliptical Curve Digital Signature Algorithm (ECDSA) Elliptic Curve Digital Signature Algorithm is the most commonly used signature type in Bitcoin. It makes use of the elliptic curve cryptography keypairs referenced in Bitcoin addresses to generate secure signatures from a given message hash. Using Bitcoin Script, it is possible to create novel systems that use elliptical curve digital signatures, including R-Puzzles, multisignature scripts and Threshold Signatures.
2. Threshold Signatures There have also been practical implementations of Threshold Signatures in Bitcoin wallets and libraries, which extend Elliptic Curve signatures to enable multiple parties to participate in the creation of a signature, created from a private key that is never explicitly calculated or previously existed. When used in a transaction, a Threshold Signature is no different to a normal ECDSA signature and can be validated using OP\_CHECKSIG and related signature check opcodes.
3. Rabin Signatures Researchers at nChain have begun developing methods of validating [Rabin signatures](https://nchain.com/app/uploads/2018/09/Rabin-Signatures-in-Bitcoin-Cash-v2.pdf) in Bitcoin script. These signatures could theoretically allow for data collected outside the Bitcoin SV ledger to be evaluated and signed, allowing oracle functionality within Bitcoin transactions. Currently no practical implementation of a Rabin signature in Bitcoin Script exists.


---

# 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/wiki/cryptography-and-keys/cryptography/digital-signatures-in-bitcoin.md?ask=<question>&goal=<endgoal>
```

`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.