Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-512 hashes from any text.
What are Cryptographic Hash Functions?
A cryptographic hash function is a mathematical algorithm that maps data of arbitrary size to a fixed-size bit string. Hash functions have three key properties: they are deterministic (same input = same output), fast to compute, and practically irreversible (you cannot recover the input from the hash).
Hash Algorithms Compared
Good hash functions also exhibit the "avalanche effect" — changing a single bit in the input produces a completely different hash. This makes hashes useful for detecting even the smallest changes in data.
Common Use Cases
Frequently Asked Questions
- What is a hash function?
- A hash function takes input data of any size and produces a fixed-size output (the hash or digest). The same input always produces the same hash, but it is computationally infeasible to reverse the hash back to the original input.
- Which hash algorithm should I use?
- For general checksums, SHA-256 is the recommended choice. MD5 and SHA-1 are cryptographically broken and should not be used for security purposes. For password hashing, use bcrypt, scrypt, or Argon2 — not raw SHA/MD5.
- Is MD5 still safe to use?
- MD5 is broken for cryptographic purposes — collision attacks are practical. However, MD5 is still acceptable for non-security uses like file checksums, cache keys, and data deduplication where collision resistance is not critical.
- Can I reverse a hash to get the original text?
- No. Hash functions are one-way by design. You cannot mathematically reverse a hash. However, common passwords can be found via rainbow tables or brute force, which is why passwords should use salted, slow hashing algorithms like bcrypt.
- Is my data sent to a server?
- No. All hashing is performed in your browser using the Web Crypto API. Your text never leaves your device.