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MD2 Hash

Generate a MD2 hash from any text instantly. Everything is computed in your browser, so your input never leaves your device.

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What is MD2?

MD2 is a 128-bit cryptographic hash function developed by Ronald Rivest in 1989 and optimized for 8-bit machines. The tool generates a fixed 128-bit (32-character hexadecimal) message digest from any text or file input entirely in your browser, with no data sent to any server. While MD2 produces a one-way hash unsuitable for new security applications, the tool remains useful for legacy system compatibility, checksum verification, and non-security hashing tasks where it was previously deployed.

How MD2 works

MD2 is a message-digest algorithm that compresses input of any length into a fixed 128-bit fingerprint through a deterministic process. The algorithm works in five main steps:

  1. Padding: The input message is extended to a multiple of 16 bytes by appending padding bytes that specify how many bytes were added
  2. Checksum: A 16-byte checksum is calculated and appended using a 256-byte lookup table (S-table)
  3. Initialize Buffer: A 48-byte processing buffer is initialized to zero
  4. Transform: The padded message is processed in 16-byte blocks through 18 rounds of cryptographic transformation, updating the buffer each round
  5. Output: The first 16 bytes of the final buffer state become the 128-bit digest, displayed as 32 hexadecimal characters

Worked Example: When you hash the text "hello", the algorithm pads it to 16 bytes, appends a checksum, processes it through multiple transformation rounds, and produces a unique 32-character hexadecimal string. The same input always produces the same output, but changing even one character in the input completely changes the hash.

How to use

  1. Type or paste your text into the input box.
  2. The MD2 hash is calculated automatically as you type.
  3. Choose your output encoding (Hex or Base64) if needed.
  4. Click Copy to copy the digest to your clipboard.

Common uses

  • Generating checksums for legacy systems and databases that still use MD2 for data integrity checks
  • Creating unique identifiers for non-cryptographic purposes where consistent hashing of input data is needed
  • Verifying file integrity in older PKI certificates and digital signature systems that were deployed with MD2
  • Testing and debugging applications that include MD2 support for backward compatibility with historical data
  • Educational purposes to understand how cryptographic hash functions work and process input through deterministic algorithms
  • Validating MD2 hashes from legacy systems when migrating to modern security protocols

Frequently asked questions

Is MD2 secure for protecting passwords or sensitive data?
No. MD2 is cryptographically broken and deprecated by the IETF since 2011. Vulnerabilities discovered include preimage attacks (2004) and collision attacks (2008). Use SHA-256 or SHA-3 for any new security-critical applications.
Is MD2 reversible or can it be decrypted?
No. MD2 is a one-way hash function. Once data is hashed, it cannot be reversed to recover the original input, though brute-force attacks on MD2 are now computationally feasible due to its cryptographic weaknesses.
How long is an MD2 hash output?
MD2 always produces a 128-bit digest, typically displayed as a 32-character hexadecimal string (4 bits per character). The output length never changes regardless of whether your input is 1 byte or 1 million bytes.
Why does the same input always produce the same MD2 hash?
MD2 is a deterministic algorithm, meaning the same input will always follow the same transformation steps and produce identical output. This consistency is useful for verification but also makes MD2 vulnerable to dictionary attacks.
Does this tool require uploading my data to a server?
No. This tool runs entirely in your browser using JavaScript. Your text is never sent to any server or stored anywhere. It is completely private and works offline once the page loads.
What was MD2 originally designed for?
MD2 was created in 1989 by Ronald Rivest for digital signature applications, designed to compress large files securely before signing with RSA. It was optimized for 8-bit machines but has been superseded by stronger hash functions.