Password-based cryptography Password-based cryptography Password-based cryptography generally refers to two distinct classes of methods: Some systems attempt to derive a cryptographic key directly from a password. However, such practice is generally ill-advised when there is a threat of brute-force attack. Techniques to mitigate such attack include passphrases and iterated (deliberately slow) password-based key derivation functions such as PBKDF2 (RFC 2898). Password-authenticated key agreement systems allow two or more parties that agree on a password (or password-related data) to derive shared keys without exposing the password or keys to network attack. Earlier generations of challenge-response authentication systems have also been used with passwords,
Online auction current web environment there are hundreds, if not thousands, of websites dedicated to online auction practices. There are six different basic types of online auctions: In live terms, English auctions are where bids are announced by either an auctioneer or by the bidders and winners pay what they bid to receive the object. English auctions are claimed to be the most common form of third-party on-line auction format used and is deemed to appear the most simplistic of all the forms. The common operational method of the format is that it is an ascending bid auction in which bids are