What Are Cryptographic Hash Functions?
A cryptographic hash function is a mathematical algorithm that maps data of any size to a fixed-size bit string. It is a one-way function, meaning it is practically impossible to reverse the computation.
Supported Algorithms
- MD5 (128-bit): Fast but considered insecure. Used for checksums and non-security purposes. Fast but considered insecure for cryptographic purposes. Still used for checksums.
- SHA-1 (160-bit): Legacy algorithm. Deprecated for security but still used in some version control systems. Deprecated for security. Vulnerable to collision attacks since 2017.
- SHA-256 (256-bit): Industry standard. Used in SSL/TLS, Bitcoin, and digital signatures. Part of SHA-2 family. Widely used in SSL, Bitcoin, and modern security.
- SHA-512 (512-bit): Maximum security. Recommended for password hashing and high-security applications. Strongest common hash. Used in high-security applications.
Frequently Asked Questions
Is MD5 still safe to use?
MD5 is considered cryptographically broken. Use it only for non-security purposes like file checksums. For security, use SHA-256 or SHA-512.
Can a hash be reversed?
No. Cryptographic hash functions are one-way. However, weak hashes can be found via rainbow tables. Use salted hashing for passwords.