MD5 Encrypt / Decrypt
Hash any text to MD5 or decrypt MD5 hashes via lookup
About MD5 Encrypt / Decrypt
MD5 (Message Digest Algorithm 5) is a widely-used cryptographic hash function that produces a 128-bit (32-character hexadecimal) digest from any input. While MD5 is a one-way function — meaning you cannot mathematically reverse a hash — this tool provides a reverse-lookup database covering all integers from 0 to 1,000,000. Enter any text to get its MD5 hash in real time, or enter a known hash to query the MySQL database and instantly see if it matches a number in the pre-built table.
How to Use MD5 Encrypt / Decrypt
- 1Choose "Hash (Encrypt)" to generate an MD5 hash — type any text and the 32-character hash appears instantly.
- 2Switch to "Decrypt (DB Lookup)" and paste the 32-character MD5 hash you want to reverse.
- 3Click "Decrypt" — the tool queries a MySQL database of 1,000,001 pre-computed hashes (values 0 to 1,000,000).
- 4If found, the original value is shown instantly; if not, the hash corresponds to a value outside the database range.
Common Use Cases
The database covers all integers 0–1,000,000 using a PRIMARY KEY index, so every lookup is a single indexed read — extremely fast regardless of table size.
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Frequently Asked Questions
What is MD5 and how does it work?
MD5 (Message Digest Algorithm 5) takes any input and produces a fixed 128-bit (32 hex character) hash. The same input always produces the same hash, but even a single character change produces a completely different output. MD5 was designed for cryptographic security but is now considered broken for that purpose.
Can MD5 hashes be reversed?
MD5 is a one-way function — it cannot be mathematically reversed. However, common hashes can be found in "rainbow tables" — precomputed databases mapping known inputs to their MD5 hashes. This tool provides exactly that: a lookup database for all integers 0 to 1,000,000.
Is MD5 still safe to use?
MD5 is not safe for password hashing or digital signatures — collision attacks are well-documented. However, MD5 is still widely used for non-security purposes like file integrity checks and checksums. For security-sensitive hashing, use SHA-256 or bcrypt/Argon2 for passwords.
What is the MD5 of an empty string?
The MD5 of an empty string ("") is always d41d8cd98f00b204e9800998ecf8427e. This is a well-known reference value used to test MD5 implementations.