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Bob and Alice Secure Email


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Bob and Alice want to share private messages that no one else can read.

 

Using known pseudo random number generators and commutative encryption algorithms that works with a single private key to both encrypt and decrypt messages, provide a logical method that achieves the following:

  • They can use normal text email
  • Trusted third party not required
  • No keys need to be shared
  • Secure at least to the level of perfect encryption.
  • No one else can modify their messages without their knowing it
  • No one else can block their messages without their knowing it
  • No tricks or gimmicks
  • Solution is apparently real AFAIK, though I've never been able to have it vetted it.
hints

 

 

  • Uses Commmutative Encryption, (encryption order doesn't matter)
  • sources of apparrent entropy must be reproducable when using the same PRNG key.
  • After a long delay, I Decided it was finally safe to post this once I saw the last piece of the complete solution posted on a well known, respectable website.
  • solved (without realiizing it) while working on an unrelated project (at least in purpose, if not in method ) which I was publicly sharing at the time in a twoplustwo poker theory forum under username TakenItEasy

    http://forumserver.twoplustwo.com/15/poker-theory/rig-proofing-poker-sites-possible-1476320/

  • Wow, I just read through some of that old thread and saw that I had so many wrong ideas in the beginning. In fact, the final solution was never posted, though it had gotten pretty close. Remember, the solution to this riddle is related to providing a perfect encryption method. I was trying to solve a rigg-proof card dealing method for on-line poker. The solution is embeded in the poker dealing method, but It's far from obvious. I didn't see it myself for over a year, I think.
  • Disclaimer, I am not a cryptographer though I do have a gift for logic, which isnt giving you much reason to trust me. Trust is not an easy problem to solve, and since I'm not a professional, I need to warn you that I don't know any vetting techniques either.

     

    If you like solving logic riddles you probably know its quite a bit tougher if you don't actually know if there is a solution. It's a matter of not knowing when to quit. Since I hate quiting but I wouldn't want to spend eternity trying to solve an unsolvable problem either, I never try to solve any problem without a known solution. Unless, of course I had to solve a problem as part of the goals I was tring to achieve, (and still trying)

     

    Therefore, I've listed all the sources that should provide the answer. You can treat them as more hints if you like, though reading just the first one is a major spoiler so you may want to wait till you've tried to solve the problem. It's probably one of the tougher problems I've solved but theres really not much to the answer either. logic is both strange and ficle. The more effort you put into it the more elegant and transparent a solution becomes. Eventually you realize that It's kind of like having all the right skills, knowledge, and experience all at the same time. Eventually the last piece falls into place and you just get hit with an epiphany. It's just like poker, when you suddenly get a strong hunch, which never seems to fail. Thats when all the right experiences, all the right skills, and all the right knowledge are collected together. Missing a single piece could leave you without a solution. or skills may take you part of the way filling in some of the gaps. But inevitibly it seems to always fall on having the last piece, once you have everything, then the solution just hits you seemingly out of nowhere and you just know the solution.

     

    Problem solving is probably my greatest gift, and fmortune really does follow the prepaired, but theire's also a certain element of luck to it as well, and you may anlready have everything you need to solve the problem, despite no one solving it for a very long time, which is a lot like poker. So while fortune definitely does follow the prepaired, I can definitely also say, you just never know until you try, and just like anything else, the more you try the better you get at trying.

  • Mental Poker (note the connection to the origional problem I was trying to solve.)
  • Three Pass Protocol (written by the same authors of Mental Poker)
  • Perfect Encryption (the last step)
  • One Time Pad (kind of built into Perfect encryption. I don't think it's actually necessary, but since I havent completely vetted the solution myself (I wouldn't know how), I list it just in case.

     

    As you know, Heisenberg showed that nothing is completely certain. As someone else said, there's no such thing as perfect security. Yeah, I saw this myself, but not in any relavent way, which makes me think people are just looking for something to blame. As I saw it, it's much more like Heisenberg Uncertainty then in any way that is relavent, at least in the near future.

     

    Computers may be starting to approach their limits, though I haven't followed computer tech since I retired a long time ago, I did know something about it. As far as Quantum computers go. I doubt anyone here has access, so, for arguements sake, at least for the purposes of solving this interesting puzzle (IMO) let's assume they don't exist.

 

 

Cross posted in the twoplustwo puzzles forum under user name TakenItEasy (not TakenItSeriously)

http://forumserver.twoplustwo.com/59/puzzles-other-games/testing-my-constitutional-rights-1666637/#post52202148

Edited by TakenItSeriously
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The sender Alice locks the box with her padlock Alpha and sends it to Bob. Bob locks the box with his padlock Beta as well as leaving padlock Alpha in place (he has no key to Alpha) and returns box to Alice. Alice undoes her padlock Alpha and leaves Bob's padlock Beta (which she has no key to) on the box - she returns that to Bob. Bob unlocks his padlock Beta and gets contents of box.

 

Commutative algorithms allow Alice to do the unlocking of her encryption whilst Bobs is still viable and without disrupting it.

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Spoilers please.

 

 

The sender Alice locks the box with her padlock Alpha and sends it to Bob. Bob locks the box with his padlock Beta as well as leaving padlock Alpha in place (he has no key to Alpha) and returns box to Alice. Alice undoes her padlock Alpha and leaves Bob's padlock Beta (which she has no key to) on the box - she returns that to Bob. Bob unlocks his padlock Beta and gets contents of box.

 

Commutative algorithms allow Alice to do the unlocking of her encryption whilst Bobs is still viable and without disrupting it.

 

 

 

 

Correct on the first part! You never fail to amaze. But it's not quite that easy either.

 

That protocal alone does not guarantee that code breaking techniques wont work.

Also, it doesn't prevent Man in the middle attacks which could intercept the message and then pretend to be the receiver eventially gettingor the sender to decrypt the code for him.

 

Once he has the message, he cna pretend to be the sender and game the reciever to make it appear like nothing was exploited.

 

Come to think of it, while I believe I found a solution to that part, I'm not sure a solution has been published for that part yet so I may not be able to verify it. My solution works, but their may still be a way to exploit it.

 

Damn, I'm going to have to research it a little more on that part and get back to you. I may have to settle for solving everything but man in the middle attacks without a published solution and no way to fully vet my solution, not that I feel comfortable about giving a solution for something that might still be sensitive ether. Damn NSA has no protocol for handling this that I knownof and it would probly be top secret if they did have a protocol anyway. You can't disagree with them but they make it impossible to agree with them as well. but what they don't seem to get is that top secret spy stuff eventually must fail. It's simply not a valid solution anymore, but theirs no reasoning with the blind, deaf, and dumb, which is why it fails.

 

Cyber War can only escalate as long as top secret protocols are in place. theres no way to de-escalate, or quite or surrender, or win, or lose, or establish rules of engagement, or establish anything, when you cant communicate with your enemy, even if you knew who your enemy was which is also impossible to know.

 

This much I don't mind taking about.

 

Even within your own country when most of your own government is'nt trusted to know anything, and you cant even discus anything within the organization itself. I used to think at least their had to be one person in charge, but apparently it's not the person in charge of the NSA which makes it all fail. Because, theirs no oversite and theirs no guarantee that any communication with the one man in charge is even happening, .

 

And with only attacks and no communication, how much do you think anyone is going to feel like being reasonable human beings, culpable deniability my ass. Its a childs excuse to keep doing anything they want to do. I could go on with this, but I need to stop before I say something that forces their hand to act without thinking, hopefully thinking about top secret stuff is still allowed, but the system is set up so that even thinking isn't a viable option anyway.

 

 

Edited by TakenItSeriously
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