Why on a flash drive?
Convenience: Most programs must be installed directly on a computer or mobile device. That's in part so that the provider can limit use to people who have paid for the program. But MarpxPrivacy is free. So you can enjoy the convenience of using a flash drive installation on many different PCs. Caution -- that does not mean every Windows PC. Don't use it on a public PC or on one in which there might be keystroke tracking. Don't use it on your company's PC if its system administrators have not yet reviewed MarpxPrivacy. As for old PCs, Windows XP and earlier, you would have to try it to see whether it might work.
Safety for PCs and for networks: MarpxPrivacy installation packs and program are entirely free of malevolent software. We stake our reputation on that. Navigate in Windows Explorer / "My Computer" to MarpxPrivacy.exe or to either installation pack, right click on it, choose properties, then the tab marked "Digital Signatures". A code-signing certification is shown to you. In other words, Marpex Inc. takes responsibility for its software. MarpxPrivacy does not of its own accord write to the host computer or to any network; it makes files only on the flash drive. The user may choose to write encrypted or decrypted files to the computer, but the default (and our recommendation) is to write them to the flash drive. When a flash drive installation is used for MarpxPrivacy, the intention is that the computer provides nothing more that the computing cycles needed. I am Doug Lowry, the second deputy assistant to the caretaker of Marpex Inc. and I approve of this message. (I'm also inventor, programmer, patent writer, and -- oh, yes -- President of Marpex Inc. of Steubenville, Ohio.)
Security for you: On a flash drive, your mission-critical information can be kept always on your person, not left in an empty office overnight. And a flash drive is much easier to keep out of sight than a laptop. It gets even better below.
How do I install?
At https://BuyExtremeEncryption.com, select MarpxPrivacyZip.exe and download it onto a flash drive. Double click on MarpxPrivacyZip.exe and select the top level of the flash drive (for example, G:\) as your preferred location for MarpXPrivacy and all its support files. The files will all appear and you are ready to use the program.
How do I run the program?
The only difference with a flash drive is that you do not have a desktop icon to launch the program. Instead, plug the flash drive into a suitable PC (not public, not restricted by system administrators). Then double click on MarpxPrivacy.exe in the MarpxPrivacy directory.
From there on, everything is identical to operating the program on a PC. We recommend that you write your encrypted and decrypted files to the MyPrivacy directory directly on the flash drive, then disperse them as you see fit later.
For the ultimate in security...
Repeatedly in these notes you will see suggestions that you use a surplus PC that is never connected to the Internet for all your privacy work. What is not connected can never be hacked. If you are in an office in which multiple people each have a MarpxPrivacy flash drive, then one low cost computer can serve multiple people's needs. Use MarpxPrivacy on your flash drive to make your content secure or to recover files and messages that are in encrypted form. Then transport your content to your own device (not necessarily a Windows PC!) for transmitting or whatever purpose you have in mind.
Are you worried about the possibility of losing your flash drive? Here's a simple trick. Notice a file named "Roster.txt.enc" in the MarpxPrivacy directory. It's encrypted. Encrypt it a second time with the manual keys option. Use whatever seven character code you like. Store the double encrypted roster file anywhere you like, in plain sight on a computer or in the cloud. If that doesn't seem enough, encrypt the double-encrypted file yet again. Just be sure to keep some record of the keys you choose, and put that record away in a safe place.
Use the same backup method with any .PKE.enc files in your MarpxPrivacy\PKEs directory. When double or triple encrypted, these files too may be stored in the cloud or in plain sight on a computer. Ideally, you would make backup copies each time you add a new PKE file to your collection or make a change in your roster.
With backup in hand, you can get a fresh copy of the program (free) anytime you wish. Then bring your backup files into place and decrypt each file in reverse order. You are then back where you where, with nothing lost. If some other person finds the lost flash drive, he/she can use it in manual keys mode, but has no ability to get at your content.
If you are the kind of person who misplaces things such as flash drives, and you want even more security? You could routinely double encrypt the "roster.txt.enc" file every time you leave the program, back up a copy, and then deliberately delete "roster.txt.enc". Then no-one has any hope of getting at your stuff. The downside: You won't either if you forget where you put the backup and the key that you used to encrypt it. Of course, if you delete "roster.txt.enc" routinely, you will also routinely have to decrypt the double-encrypted version every time you start MarpxPrivacy. But one way or another you should be able to keep your files and messages secure.