1. Introduction

   This document provides recommendations for the implementation of
   password-based cryptography, covering the following aspects:

   -  key derivation functions
   -  encryption schemes
   -  message-authentication schemes
   -  ASN.1 syntax identifying the techniques

   The recommendations are intended for general application within
   computer and communications systems, and as such include a fair
   amount of flexibility. They are particularly intended for the
   protection of sensitive information such as private keys, as in PKCS
   #8 [25]. It is expected that application standards and implementation
   profiles based on these specifications may include additional
   constraints.

   Other cryptographic techniques based on passwords, such as password-
   based key entity authentication and key establishment protocols
   [4][5][26] are outside the scope of this document.  Guidelines for
   the selection of passwords are also outside the scope.

   This document supersedes PKCS #5 version 1.5 [24], but includes
   compatible techniques.