MD5 / SHA Hash Generator
Last updated: June 2026 · Free · No sign-up required
Frequently Asked Questions
What is a cryptographic hash?
A cryptographic hash function is an algorithm that takes an input of any size and returns a fixed-size string of bytes (the hash). A secure hash is one-way, meaning it is computationally impossible to reverse the process to find the original input.
Can MD5 or SHA-1 hashes be reversed?
MD5 and SHA-1 are cryptographically broken and vulnerable to collision attacks (where different inputs produce the same hash). While they cannot be directly 'reversed', database lookups of pre-computed hashes (rainbow tables) can often reveal the original input for common strings.
Which hashing algorithm is the most secure?
Among the options provided, SHA-512 and SHA-256 are the most secure and are widely recommended for checking data integrity and secure computations.
Quick reference
| Algorithm | Digest size | Status |
|---|---|---|
| MD5 | 128-bit (32 hex) | Broken — checksums only |
| SHA-1 | 160-bit (40 hex) | Deprecated for security |
| SHA-256 | 256-bit (64 hex) | Current standard |
| SHA-512 | 512-bit (128 hex) | Current standard |
Interpretation guide
| Use case | Pick |
|---|---|
| File/text integrity check | SHA-256 |
| Legacy system compatibility | MD5/SHA-1 as required |
| Password storage | None of these — use bcrypt/argon2 |
Formula & methodology
Formula: digest = H(UTF-8 bytes of input); deterministic, fixed length, one-way
- Type or paste any text.
- The browser’s WebCrypto API (and a JS MD5 implementation) hash the UTF-8 bytes locally — nothing is uploaded.
- All four digests appear in lowercase hex, ready to copy.
Worked example: the string "hello" always yields SHA-256 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824 — change one letter and the entire digest changes (the avalanche effect).