One popular authentication technique that depends on safe password storage is password authentication. putting out a framework for password-safe secure password storage that is easily incorporated into current authentication systems. The naked password is first hashed by a cryptographic hash function (e.g., SHA-256) before being sent to the client. The hashed password is then changed to a negative password so that it cannot be used again. Lastly, the derived negative password is encrypted using a symmetric-key approach to create an Encrypted Negative Password (abbreviated as "ENP"), such as AES. To further improve security, multi-iteration encryption can be employed. Because of the symmetric encryption and cryptographic hash function, ENP passwords are difficult to decipher. Then, in order to increase its security even further, the decrypted negative password is re-encrypted using the RSA algorithm.

hashed password, symmetric key method, and encrypted negative password