-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Hi there,
I think this is a good topic for debate among those who can or are currently developing security tools/protocols, and it is one way to further discuss usability as a security feature in communities like this one. That said, I think it is really bad advice and I encourage you to refrain from providing this as a suggestion for users who may put themselves or others at risk as a result of it. Also, I think the title is misleading, as most of the article is about why PGP is not an ideal solution for the future (a point where I think you would find significant agreement). Again, suggesting not to use PGP without providing a functional alternative is irresponsible. Best, Enrique - -- Enrique Piracés Vice President, Human Rights Program Benetech https://www.benetech.org https://www.martus.org https://www.twitter.com/epiraces On 10/10/13 3:23 PM, carlo von lynX wrote: > We had some debate on this topic at the Circumvention Tech Summit > and I got some requests to publish my six reasons not to use PGP. > Well, I spent a bit more time on it and now they turned into 10 > reasons not to. Some may appear similar or identical, but actually > they are on top of each other. Corrections and religious flame wars > are welcome. YMMV. > > > > ---------------------------------- TEN REASONS NOT TO START USING > PGP ---------------------------------- Coloured version at > http://secushare.org/PGP > > > > [01]Pretty Good Privacy is better than no encryption at all, and > being [02]end-to-end it is also better than relying on [03]SMTP > over [04]TLS (that is, point-to-point between the mail servers > while the message is unencrypted in-between), but is it still a > good choice for the future? Is it something we should recommend to > people who are asking for better privacy today? > > 1. Downgrade Attack: The risk of using it wrong. > > Modern cryptographic communication tools simply do not provide > means to exchange messages without encryption. With e-mail the risk > always remains that somebody will send you sensitive information in > cleartext - simply because they can, because it is easier, because > they don't have your public key yet and don't bother to find out > about it, or just by mistake. Maybe even because they know they can > make you angry that way - and excuse themselves pretending > incompetence. Some people even manage to reply unencrypted to an > encrypted message, although PGP software should keep them from > doing so. > > The way you can simply not use encryption is also the number one > problem with [05]OTR, the off-the-record cryptography method for > instant messaging. > > 2. The OpenPGP Format: You might aswell run around the city naked. > > As Stf pointed out at CTS, thanks to its easily detectable > [06]OpenPGP Message Format it is an easy exercise for any > manufacturer of [07]Deep Packet Inspection hardware to offer a > detection capability for PGP-encrypted messages anywhere in the > flow of Internet communications, not only within SMTP. So by using > PGP you are making yourself visible. > > Stf has been suggesting to use a non-detectable wrapping format. > That's something, but it doesn't handle all the other problems with > PGP. > > 3. Transaction Data: He knows who you are talking to. > > Should Mallory not [08]possess the private keys to your mail > provider's TLS connection yet, he can simply intercept the > communication by means of a [11]man-in-the-middle attack, using a > valid fake certificate that he can make for himself on the fly. > It's a bull run, you know? > > Even if you employ PGP, Mallory can trace who you are talking to, > when and how long. He can guess at what you are talking about, > especially since some of you will put something meaningful in the > unencrypted Subject header. > > Should Mallory have been distracted, he can still recover your > mails by visiting your provider's server. Something to do with a > PRISM, I heard. On top of that, TLS itself is being recklessly > deployed without forward secrecy most of the time. > > 4. No Forward Secrecy: It makes sense to collect it all. > > As Eddie has told us, Mallory is keeping a complete collection of > all PGP mails being sent over the Internet, just in case the > necessary private keys may one day fall into his hands. This makes > sense because PGP lacks [12]forward secrecy. The characteristic by > which encryption keys are frequently refreshed, thus the private > key matching the message is soon destroyed. Technically PGP is > capable of refreshing subkeys, but it is so tedious, it is not > being practiced - let alone being practiced the way it should be: > at least daily. > > 5. Cryptogeddon: Time to upgrade cryptography itself? > > Mallory may also be awaiting the day when RSA cryptography will be > cracked and all encrypted messages will be retroactively readable. > Anyone who recorded as much PGP traffic as possible will one day > gain strategic advantages out of that. According to Mr Alex Stamos > that day may be closer than PGP advocates think as [13]RSA > cryptography may soon be cracked. > > This might be true, or it may be counter-intelligence to scare > people away from RSA into the arms of [14]elleptic curve > cryptography (ECC). A motivation to do so would have been to get > people to use the curves recommended by the NIST, as they were > created using magic numbers chosen without explanation by the NSA. > No surprise they are suspected [15]to be corrupted. > > With both of these developments in mind, the alert cryptography > activist scene seems now to converge on [16]Curve25519, a variant > of ECC whose parameters where elaborated mathematically (they are > the smallest numbers that satisfy all mathematical criteria that > were set forth). > > ECC also happens to be a faster and more compact encryption > technique, which you should take as an incentive to increase the > size of your encryption keys. It is up to you to worry if it's more > likely that RSA or ECC will be cracked in future, or you may want > to ask a mathematician. > > 6. Federation: Get off the inter-server super-highway. > > NSA officials have been reported saying that NSA does not keep > track of all the peer-to-peer traffic as it is just large amounts > of mostly irrelevant copyright infringement. It is thus a very good > idea to develop a communications tool that embeds its ECC- > encrypted information into plenty of P2P cover traffic. > > Although this information is only given by hearsay, it is a > reasonable consideration to make. By travelling the > well-established and surveilled paths of e-mail, PGP is > unnecessarily superexposed. Would be much better, if the same PGP > was being handed from computer to computer directly. Maybe even > embedded into a picture, movie or piece of music using > [17]steganography. > > 7. Statistical Analysis: Guessing on the size of messages. > > Especially for chats and remote computer administration it is > known that the size and frequency of small encrypted snippets can > be observed long enough to guess the contents. This is a problem > with SSH and OTR more than with PGP, but also PGP would be smarter > if the messages were padded to certain standard sizes, making them > look all uniform. > > 8. Workflow: Group messaging with PGP is impractical. > > Have you tried making a mailing list with people sharing private > messages? It's a cumbersome configuration procedure and > inefficient since each copy is re-encrypted. You can alternatively > all share the same key, but that's a different cumbersome > configuration procedure. > > Modern communication tools automate the generation and distribution > of group session keys so you don't need to worry. You just open up > a working group and invite the people to work with. > > 9. TL;DR: I don't care. I've got nothing to hide. > > So you think PGP is enough for you since you aren't saying > anything reaaally confidential? Nobody actually cares how much you > want to lie yourself stating you have nothing to hide. If that was > the case, why don't you do it on the street, as John Lennon used to > ask? > > It's not about you, it's about your civic duty not to be a member > of a predictable populace. If somebody is able to know all your > preferences, habits and political views, you are causing severe > damage to democratic society. That's why it is not enough that you > are covering naughty parts of yourself with a bit of PGP, if all > the rest of it is still in the nude. Start feeling guilty. Now. > > 10. The Bootstrap Fallacy: But my friends already have e-mail! > > But everyone I know already has e-mail, so it is much easier to > teach them to use PGP. Why would I want to teach them a new > software!? > > That's a fallacy. Truth is, all people that want to start > improving their privacy have to install new software. Be it on top > of super-surveilled e-mail or safely independent from it. In any > case you will have to make a [18]safe exchange of the public keys, > and e-mail won't be very helpful at that. In fact you make it easy > for Mallory to connect your identity to your public key for all > future times. > > If you really think your e-mail consumption set-up is so amazing > and you absolutely don't want to start all over with a completely > different kind of software, look out for upcoming tools that let > you use mail clients on top. Not the other way around. > > But what should I do then!?? > > So that now we know 10 reasons not to use PGP over e-mail, let's > first acknowledge that there is no easy answer. Electronic privacy > is a crime zone with blood freshly spilled all over. None of the > existing tools are fully good enough. We have to get used to the > fact that new tools will come out twice a year. > > Mallory has an interest in making us believe encryption isn't going > to work anyway - but internal data leaked by Mr Snowden shows that > encryption actually works. We should just care to use it the best > way. That means, not with PGP. > > There is no one magic bullet you can learn about. > > You have to get used to learning new software frequently. You have > to teach the basics of encryption independently from any software, > especially from the one that does it wrong the most. > > In the [09]comparison we have listed a few currently existing > technologies, that provide a safer messaging experience than PGP. > The problem with those frequently is, that they haven't been peer > reviewed. You may want to invest time or money in having projects > peer reviewed for safety. > > Pond is currently among the most interesting projects for mail > privacy, hiding its padded undetectable crypto in the general noise > of Tor. Tor is a good place to hide private communication since the > bulk of Tor traffic seems to be anonymized transactions with > Facebook and the like. Even better source of cover traffic is file > sharing, that's why RetroShare and GNUnet both have solid file > sharing functionality to let you hide your communications in. > > Mallory will try to adapt and keep track of our communications as > we dive into cover traffic, but it will be a very hard challenge > for him, also because all of these technologies are working to > switch to Curve25519. Secushare intends to only support Curve25519 > to impede [10]downgrade attacks. Until the next best practice comes > out. It's an arms race. Time to lay down your old bayonet while > Mallory is pointing a nuclear missile at you. > > Thank you, PGP. > > Thank you Mr Zimmermann for bringing encryption technology to the > simple people, back in 1991. It has been an invaluable tool for > twenty years, we will never forget. But it is overdue to move on. > > References > > 01. https://en.wikipedia.org/wiki/Pretty%20Good%20Privacy 02. > http://secushare.org/end2end 03. > https://en.wikipedia.org/wiki/SMTP 04. > https://en.wikipedia.org/wiki/TLS 05. > https://en.wikipedia.org/wiki/Off-the-Record_Messaging 06. > http://tools.ietf.org/html/rfc4880 07. > https://en.wikipedia.org/wiki/Deep_packet_inspection 08. > http://www.theguardian.com/world/2013/sep/05/nsa-gchq-encryption-codes-security > > 09. http://secushare.org/comparison > 10. > http://crypto.stackexchange.com/questions/10493/why-is-tls-susceptible-to-protocol-downgrade-attacks > > 11. http://en.wikipedia.org/wiki/man-in-the-middle%20attack > 12. https://en.wikipedia.org/wiki/Forward_secrecy 13. > http://www.heise.de/tr/artikel/Die-Krypto-Apokalypse-droht-1942212.html > > 14. https://en.wikipedia.org/wiki/Elliptic_curve_cryptography > 15. > http://www.wired.com/threatlevel/2013/09/rsa-advisory-nsa-algorithm/ > > 16. https://gnunet.org/curve25519 > 17. https://en.wikipedia.org/wiki/steganography 18. > http://secushare.org/rendezvous > > P.S. > > Thanks for feedback to tg, duy and especially Mr Grothoff. > -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.20 (Darwin) Comment: GPGTools - https://gpgtools.org iQEcBAEBCgAGBQJSVxRLAAoJEDU0GlswZf+d7UQH/0pn157xP9AmSawV93Oced8v Sfy/lNudnO+beZ/TPLsYkD+Hd/AjcRDdX+h7f6r+5AWsKpHtDdCQ8NTzWchDAwtr 2sLqXILAAavqAbtzzZO7mQs98r0WJimhmJCizxYW/LgjhDEQ+vryCpBqkvaH5sth dM6bJCPJ6zad83ZARM0KNyYme3Jw1tAxqZJJLtsi/U/eqCqawcVy5WO7a3U4T/TP 0Q9rlYxheUpB9bB/PLJ5brpgFvpXpm0Wv27ocKQAHA0RjugbM24Zuap77MtWqSen GXy089iikDhD7DS3GH0re6dNtpvZDPj3PgaG4UuPTPBjIMo4CenBYtPc3JICjXM= =G3UK -----END PGP SIGNATURE----- -- Liberationtech is public & archives are searchable on Google. 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