On Mon, Apr 04, 2016 at 06:26:29AM -0700, Sugumar wrote: > I going to use SHA256 algorithm for storing my passwords in secure manner. > But after reading some documentations related to SHA i come to know it is > not reversable. > Yes hashing means its not reversable only. > But i saw some online websites giving the original data by reversing the > hash data. > is it possible means what is the security of hashing? > I am totally confused pls clarify my doubt. Unsalted hashes (regardless of the algorithm) are vulnerable to rainbow table assisted dictionary attacks. This is a space/time tradeoff that makes lookup a bit slower but reduces the storage cost to manageable levels. So there is no explicit inversion, just reasonably efficient guess and compare dictionary attacks. -- Viktor.
