Research And Implementation Of Disk Passphrase Retrieve Technology On PGP Desktop

Whether in the traditional communication era,or in the current Internet age,the importance of personal information security has never changed.In particular,taking into account frequent information disclosure incidents and cyber scams,everyone should pay more attention to protecting personal information and privacy than ever before.PGP Desktop has a number of features that can protect our important data and information.However,no mater what kind of data that user want to encrypt by using PGP Desktop,a passphrase should be set when encrypting the data.This passphrase can be used to verify the legitimacy of the user when decrypting the data.If the user forgets the passphrase used for encrypting the data after a certain period of time,these encrypted important data will never be decrypted again.What we have done in this research is to help the PGP Desktop users resolving problem that they may forget the passphrase which they have used to protect their data or information.Disk encryption is one of the most important features of PGP Desktop,which can encrypt two types of disks,vitraul disks and physical disks.Each kind of disk supports two types of users,key ring users and passphrase users.The difference between the two types of users is that the key ring user protect the session key by using asymmetric encryption algorithms while the passphrase user using symmetric algorithms.Furthermore,the passphrase of key ring user is used to protect user's private key while the passphrase of passphrase user is used to protect session key directly.What we focus on in this research is how to retrieve the passphrases of both two types of users in virtual disks and physical disks.At present,there is very little work on this area,and no one has studied how to retrieve passphrase of passphrase user from physical disk.In order to achieve the purpose of the research,we firstly analyze the structure of the disk and its hexadecimal data,and then find the parameters that are related to the user's authentication.Secondly figure out the meaning of these parameters according to source code of PGP system and study the procedure of different user passphrase verification in different disk.Finally search the user's passphrase in possible passphrase sets by way of enumerating.In order to verify the feasibility and performance of this research,a program will be developed by using Microsoft Visual Studio 2015.At last,there are three schemes proposed in this paper,the universal key ring user's passphrase retrieve scheme,the passphrase retrieve scheme of passphrase user in virtual disk and the passphrase retrieve scheme of passphrase user in physical disk.Respectively,comparing with the similar scheme,the first scheme can retrieve both of RSA and DH key ring user's passphrase.In addition,the third scheme are proposeed for the first time,and no one else has proposed.