CodePudding user response:
Is don't say SHA512, SHA1 also don't want to decrypt, SHA algorithm technically is not encrypted, just hash (similar to the MD5), through the hash algorithm will drift long hash data into fixed summary, so in theory there is the possibility of collision (different data resulting from the hash of the A and B are the same), the so-called this kind of website, is built in A database, the common data (such as 45, 1123 A, etc.) the hash results are saved to the database, and then according to the hash value (that is, the so-called encrypted data) reverse lookup clear, if the original data is not common, the built-in database does not exist, can not find A clear, cannot decrypt,