# Quiz 16 #### What are the key properties of the ephemeral key used in ECDSA? * [x] It must be random and unpredictable * [x] It is used only once per signature * [x] Weak randomness can compromise private keys * [ ] It is derived from the public key * [ ] It is shared with the verifier **Note to Learners** For security, every signature must use a new, unpredictable ephemeral key. If the randomness is biased or predictable, attackers can break the signature scheme and recover private keys. To learn more about it, you can follow the course [Elliptic Curve Digital Signature Algorithm (ECDSA)](https://bsvblockchain.360learning.com/course/play/68dcfb7db22b823a03f88909) --- # 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://hub.bsvblockchain.org/higher-learning/bsv-academy/bitcoin-primitives-digital-signatures/quiz/quiz-16.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.