Evolution of Password Storage Methods

The history of password storage reflects an ongoing arms race between defenders and attackers. Early systems stored passwords in plaintext, providing no protection against unauthorized access. The introduction of one-way hash functions in the 1970s represented a major advance, allowing systems to verify passwords without storing them directly. However, the computational limitations of that era meant using fast hash functions that modern hardware can defeat easily.

The discovery of hash collisions and the development of rainbow tables forced another evolution in password storage. Salting emerged as a countermeasure, adding random data to passwords before hashing to defeat precomputed attacks. However, many implementations used predictable or reused salts, limiting their effectiveness. The need for unique, cryptographically random salts per password became a fundamental security requirement.

Modern password storage has shifted from fast general-purpose hash functions to specialized password hashing algorithms. Functions like bcrypt, scrypt, and Argon2 incorporate deliberate computational expense and memory requirements to resist hardware-accelerated attacks. These algorithms can be tuned to remain secure as computing power increases, providing long-term protection for stored passwords. The evolution continues with emerging threats like quantum computing requiring new approaches to password security.