MD4 (Message Digest 4) is a 128-bit cryptographic hash function designed by Ron Rivest in 1990 and specified in RFC 1320. It was a precursor to MD5 and was widely used in the 1990s. Today it is considered cryptographically broken — collision attacks are practical — so it should not be used for security-sensitive applications.

Why would I still need MD4?

MD4 appears in several legacy and specialized contexts: NTLM (NT LAN Manager) authentication uses a single MD4 hash of the UTF-16 password as the NT hash; eDonkey/eMule file sharing uses MD4 in its file-link scheme; and some older databases or protocols store MD4-based identifiers. Forensic and penetration-testing work often requires reproducing these values.

Is my input sent to a server?

No. The entire MD4 algorithm runs inside your browser as pure JavaScript. Nothing is transmitted to any server. You can even disconnect from the internet after loading the page and the tool will still work.

How does MD4 differ from MD5?

MD4 uses only 3 rounds of 16 operations each (48 operations total), while MD5 adds a fourth round and more nonlinear functions for a total of 64 operations. Both produce a 128-bit (32 hex character) digest, but MD5 is significantly more resistant to collision attacks than MD4. Neither algorithm is recommended for new security-sensitive work.

What is the NTLM hash and how does MD4 relate to it?

The NTLM NT hash is computed by encoding the password as UTF-16LE and then running a single MD4 hash over those bytes. This tool hashes UTF-8 encoded text, which matches standard MD4 usage. For NTLM specifically, your input must be the raw UTF-16LE byte sequence of the password — a detail relevant mainly to security researchers.

Why is the output always 32 characters?

MD4 always produces a fixed 128-bit (16-byte) digest regardless of input length. When those 16 bytes are encoded as lowercase hexadecimal (2 characters per byte), the result is always exactly 32 characters.

MD4 Hash Generator

Type or paste any text and instantly get its MD4 hash — computed locally in your browser with no data sent to any server.

Input Text 0 characters

Uppercase output Trim whitespace

About MD4

MD4 (RFC 1320) is a 128-bit legacy hash algorithm by Ron Rivest (1990). It is the foundation of NTLM authentication and eDonkey file hashing. MD4 is considered cryptographically broken — do not use it for security-sensitive applications. Use SHA-256 or stronger for new designs.

MD4 Hash 32 hex characters

Enter text on the left to generate the hash

MD-Family Comparison

Algorithm	Bits	Status
MD4	128	Broken
MD5	128	Broken
SHA-1	160	Weak
SHA-256	256	Secure

Summary

The MD4 Hash Generator computes an MD4 cryptographic digest from any text you provide, entirely within your browser using a pure-JavaScript implementation. MD4 is a 128-bit message digest algorithm designed by Ron Rivest in 1990 and is the predecessor to MD5. Although considered cryptographically broken for security-sensitive applications, MD4 remains relevant for legacy system compatibility, NTLM password hashing, and digital forensics work.

How it works

Type or paste your input text into the text area.
The MD4 digest is computed live in your browser using a pure-JavaScript implementation of RFC 1320.
The result is displayed as a 32-character lowercase hexadecimal string.
Toggle uppercase output if your target system requires it.
Use the Copy button or click the hash directly to copy it to your clipboard.
No data leaves your device — all computation happens entirely client-side.

Use cases

Compute NTLM password hashes for Active Directory and Windows authentication testing.
Verify legacy system checksums that rely on MD4 digests.
Reproduce MD4-based identifiers used in older database schemas or protocols.
Assist digital forensics analysis by matching known MD4 hash values.
Test and debug cryptographic pipelines that include MD4 as an intermediate step.
Study hash algorithm behavior and compare MD4 output against MD5 or SHA-1.
Generate Ed2k file link hashes (eDonkey/eMule peer-to-peer network uses MD4).
Validate output from server-side MD4 implementations against a known-good value.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu