In the cybersecurity landscape, we all need hashes! A hash is the result of applying a special mathematical function (a “hash function”) that transforms an input (such as a file or a piece of text) into a fixed-size string or number. This output, often called a “hash value,” “digest,” or “checksum,” uniquely represents the original data. In the context of this diary, hashes are commonly used for data integrity checks. There are plenty of them (MD5, SHA-1, SHA-2, SHA-256, …), SHA256 being the most popular for a while because older like MD5 are considered as broken because researchers have demonstrated practical collision attacks.