# Assessment 7 #### What does it mean for a hash function to be preimage resistant? * [x] It is computationally infeasible to find an input from a message digest * [ ] It is easy to find an input from a message digest * [ ] It is easy to reverse the hash function * [ ] It is deterministic **Notes to Learners** Said in another way, hash functions are one-way 'trap-door' functions; they make it easy to find a message digest from an input, but so difficult to find an input from a message digest. --- # 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/hash-functions-crash-course/assessment-7.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.