MD5, MD5 (Message Digest 5), an old cryptographic hash function developed by Ron Rivest in 1991. Collision attacks were found in 2004 and it is considered insecure for cryptographic purposes.
Technical Specifications
- Hash Length:
- 128 bit (32 hex characters)
- Block Size:
- 512 bit
- Maximum Message Size:
- 2^64 - 1 bit
- Status:
- Insecure - Should NOT be used for cryptographic purposes
Usage Areas
- File integrity verification (non-cryptographic purposes)
- Legacy systems and applications
- Download verification (as non-cryptographic checksum)
Features
- Fast computation: Simple and fast algorithm
- Deterministic: Same input always produces the same hash
Standards and References
- RFC 1321 (deprecated)
⚠️ Important Warnings
- Cryptographically insecure: Vulnerable to collision attacks (collision found in 2004)
- Vulnerable to preimage attacks
- Should NOT be used for cryptographic purposes
- Modern applications should use secure algorithms like SHA-256, SHA-3, or BLAKE2
- NEVER use for password hashing
- NEVER use for digital signatures