what is a hash in cryptography 
a hash is a mathematical function that converts a variable input to a deterministic hexadecimal number the bottom linein a cryptocurrency blockchain a hash is a deterministic hexadecimal number this means that no matter how many characters the input has the hash will always be the same number of characters for instance bitcoin s hashes are always 64 digits hashes are used to secure information in the case of cryptocurrency they are used to ensure data contained in the blocks on a blockchain are not altered the information encrypted by the hashing function is validated by network participants when they attempt to generate a hash less than the network target once the target hash is reached the network closes the block consensus is reached after the block closes because the network continues to validate transactions and block information after the hash solution is found the comments opinions and analyses expressed on investopedia are for informational purposes online read our warranty and liability disclaimer for more info 