Hash

Hash is a function that converts any given data into a fixed length set of numbers. It is a one-way function which means that just by looking at the hash of a data, it is almost impossible to tell what the original data was. Hashes can’t be decrypted back. Block hash is the mathematical problem the miners’ computer needs to solve. A Bitcoin block hash looks like this: 00000000000000000023c7c38b37a7ff6b8571cd8d9fa54adf985c7defe3b65b