Vortex16
Vortex Level 16 — find 100 bits out of a 128-bit randomly generated hashed key, a partial hash-matching problem.
Table of Contents
Source: This content is aggregated from overthewire (MIT). Visit the original repository for the latest version.
The BOFH
This level requires finding 100 bits out of a 128 bit randomly generated hashed key. You must login to vortex.labs.overthewire.org to complete this level.
Study guide
Level map: logged in as vortex16, obtain access to vortex17.
What this level teaches
The cost and structure of partial hash search.
Key ideas
- The task as stated. The page describes it as finding 100 bits out of a randomly generated, hashed 128-bit key. Read the level’s code to see exactly which bits must match and what you control.
- Cost estimation. Matching fewer bits is exponentially cheaper than matching all of them: each extra required bit roughly doubles the expected work.
- Speed. Efficient C and parallel search make the difference between hours and years.
How to approach it
- Read exactly what must match, and how many bits.
- Estimate expected work for the plan you choose.
- Implement and benchmark on smaller bit counts first.
Why it matters
It illustrates truncated hashes and why a short checksum gives only weak assurance.