What is Hashing?

Hashing is the process of converting data of any size into a fixed-size string of characters, which is typically a digest that is unique to the data being hashed.

One-way

Unlike encryption, hashing is a one-way function. You cannot practically reverse the hash to get the original data back.

Comparison

MD5: Fast, produces a 128-bit hash. Considered insecure for cryptography due to collision vulnerabilities, but great for checksums.

SHA-1: Produces a 160-bit hash. More secure than MD5 but now considered weak against well-funded attackers.

SHA-256: Part of the SHA-2 family. Highly secure, used in Bitcoin and SSL certificates. 256-bit length.