MD4
Calculate a legacy MD4 hash or HMAC from text using UTF-8, Hex, Base64, and other input encodings. Read more
What is MD4?
MD4 is a fast 128-bit message-digest algorithm designed by Ronald Rivest and documented in RFC 1320. It influenced MD5 and other hash designs, and still appears in legacy systems such as NT password hashes. RFC 6150 moved MD4 to Historic status because it is no longer appropriate where collision resistance is required.
How to use this hash calculator
Enter the text, select its byte encoding, and choose the output format. Keep HMAC disabled for an MD4 digest. Enable it only to reproduce a legacy HMAC-MD4 value with the exact key encoding.
Result example
MD4 of UTF-8/ASCII abc is a448017aaf21d8525fc10ae87aa6729d in Hex.
Important limitations
Practical collision attacks make MD4 unsuitable for signatures, certificates, integrity against attackers, or new HMAC deployments. Its speed also makes unsalted password hashes easy to guess at scale. Use this calculator for compatibility and analysis, not new security designs.
Frequently asked questions
Why does my result differ from another tool?
Check bytes, encoding, line endings, and HMAC mode. When working with NT hashes, note that those systems hash the password’s UTF-16LE bytes, not its UTF-8 representation.
Can I use the result to verify data?
It can reproduce a legacy MD4 value, but a match is not strong authenticity evidence. To process raw file bytes, use MD4 File Hash.