Snefru-256 Hash Code Calculator

The Snefru hash function is a cryptographic hash function designed by Ralph Merkle in 1990. It was originally intended as part of a submission to the National Institute of Standards and Technology (NIST) during the early efforts to standardize secure hash algorithms. While it is not widely used today, Snefru is significant because it introduced ideas that influenced later cryptographic designs.

Snefru originally supported variable output sizes, but the version presented here produces a 256 bit (32 bytes) output, typically visualized as a 64 digit hexadecimal number.

Full disclosure: I did not write the specific implementation of the hash function used on this page. It is a standard function included with the PHP programming language. I only made the web interface to make it publicly available here for convenience.

About the Snefru Hash Algorithm

I'm not a mathematician nor a cryptographer, but I'll try to explain this hash function in a way that is understandable by my fellow non-mathematicians. If you prefer the math-heavy, scientifically correct explanation, I'm sure you can find that elsewhere ;-)

Although Snefru is no longer considered secure and appropriate for new systems, it's interesting for historical reasons, because its designs influenced many later hash functions that are still in use.

You can imagine Snefru like a high-powered blender designed to mix and chop ingredients up until you can no longer identify the original input, but like all hash functions, it will always give the same output for the same input.

This is a three step process:

Step 1: Chop the Ingredients (Input Data)

• First, you cut your ingredients into smaller chunks so they fit in the blender. This is like breaking data into blocks.

Step 2: Mixing Rounds (Blender on Different Speeds)

• Snefru doesn't just blend once. It does several rounds of blending - like switching between chopping, pureeing, and pulsing - to make sure everything is mixed super well.
• In each round, the blender:
  • Stirs in different directions (like flipping the smoothie upside down).
  • Adds secret "twists" (like tiny sprinkles of random flavors) to make the mix even harder to predict.
  • Changes the speed to stir differently each time.

Step 3: Final Smoothie (The Hash)

• • After 8 intense rounds of blending, you pour out the final smoothie. This is the hash - a unique-looking mixture that's completely scrambled.