Frequently Asked Questions
What is a cryptographic hash function?
A cryptographic hash function takes an input of any size and produces a fixed-size output called a hash or digest. Good hash functions are one-way (cannot be reversed), deterministic (same input always gives same output), and collision-resistant (extremely hard to find two inputs with the same hash). They are used for data integrity verification, digital signatures, and password storage.
Which hash algorithm should I use?
For security purposes (digital signatures, certificates, integrity), use SHA-256 or SHA-512. MD5 and SHA-1 are cryptographically broken and should not be used where collision resistance matters. For non-security uses (file checksums, cache keys, deduplication), MD5 is still acceptable due to its speed and shorter output.
Can I use SHA-256 for password hashing?
No. While SHA-256 is cryptographically strong, it is too fast for password hashing. Purpose-built password hashing algorithms like bcrypt, scrypt, or Argon2 are designed to be intentionally slow (to resist brute-force attacks) and include salting. SHA-256 is great for data integrity but not for storing passwords.
Is my data safe using this tool?
Yes. All hashing happens entirely in your browser. SHA hashes use the Web Crypto API (a native browser cryptographic library). MD5 uses a pure JavaScript implementation. No data is transmitted to any server. You can verify by using the tool offline.
Why are MD5 hashes still commonly used?
MD5 produces short 32-character hashes and is very fast. For non-security uses like verifying file downloads, generating cache keys, or deduplicating data, MD5 remains popular. The security vulnerabilities (collision attacks) only matter when an adversary is actively trying to craft malicious inputs.