What is MD4?
A MD4 file checksum is a hash computed over the bytes of a file. It gives you a short, fixed-length fingerprint you can compare against a published value to confirm a download was not corrupted or tampered with.
How MD4 works
MD4 is a one-way cryptographic hash. At a high level it works like this:
- Your input is padded and broken into fixed-size blocks.
- Each block is mixed into an internal state through many rounds of bitwise operations.
- After the final block, the internal state is output as a fixed-length digest.
Every input bit affects the whole result, so a single character change produces a completely different digest — and the digest cannot be reversed back into the input.
How to use
- Select or drop a file into the tool.
- The MD4 checksum is computed locally in your browser.
- Compare the result against the file's published MD4 value.
- If they match, the file is intact.
Common uses
- Verifying file and data integrity with checksums.
- Fingerprinting and deduplicating content.
- Detecting accidental corruption or changes.
- Indexing or comparing data without storing the original.
Frequently asked questions
Is my file uploaded anywhere?
No. The MD4 checksum is calculated entirely in your browser; the file never leaves your device.
Why verify a MD4 checksum?
To confirm a downloaded file is complete and has not been altered or corrupted in transit.