What is the key symbol for hash?

Excuse me, but could you clarify what you mean by the "key symbol for hash"? Are you referring to the visual representation or identifier used to denote a hash function or its output? In cryptography and computer science, a hash is a function that takes an input, such as a string of text, and produces a fixed-size output, known as the hash value. This output is typically represented as a hexadecimal string, which might be considered a "symbol" in a broader sense. However, if you're looking for a specific symbol that universally represents hashes, there isn't one that I'm aware of. Could you provide more context or elaboration on your question?