LinkedIn stored 117 million passwords as unsalted SHA-1 — cracked within days. Adobe used 3DES encryption (reversible) instead of hashing. These are the specific, named password storage mistakes that keep producing data breaches. Here's every common error, why it fails, and the correct modern approach with bcrypt and Argon2.
Hashing the same file twice, a year apart, on different computers, produces the exact same hash — this single property, determinism, is the foundation of file-integrity verification. Here's how the avalanche effect guarantees "match or no match, with no partial credit," why fixed output size makes hash comparison practical for huge files, the proper download-verification workflow, and why where a published hash comes from matters as much as the comparison itself.
Hash functions underpin Git commits, blockchain blocks, and certificate transparency logs through Merkle trees. Here's why MD5 and SHA-1 are "broken," how Merkle trees verify large datasets with O(log n) hashes, and how Bitcoin light clients verify transactions without the full blockchain.
Learn how cryptographic hash functions work, when to use MD5 vs SHA-256 vs SHA-3, the avalanche effect, why hashes can't be used for passwords, and how to use a free hash generator for integrity verification.
Learn how hash functions work, the differences between MD5, SHA-1, SHA-256, and SHA-3, which algorithm to use for file verification vs. passwords, and how to generate hashes instantly with a free tool.
