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Encryption Security

Email Clients with Encrypted Archives? 49

jasonbrown asks: "If your like a lot of us, you want to keep all your good email for later viewing. Then again, who wants to have all that personal stuff laying around when some higher power decides to dig through it. I was wondering if the Slashdot community knows of any good, preferably linux compatible, email clients with an encrypted archive to keep your old email away from prying eyes."
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Email Clients with Encrypted Archives?

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  • by zantrox ( 547904 ) on Friday January 04, 2002 @03:43AM (#2783913)
    --- BEGIN ENCRYPTED COMMENT ---
    fk9aoeka89ok7aozeka.iKHAOEKauoe7kaeyFH43%YG. ;UEIM45fyh234P!H@#$p*Kx;ep986f 214%"DuoKOHKAuQqjp.ysa98kfokntab,.p',.ntdoi
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  • This article was posted in the middle of the night. Good luck getting any answers. BTW reading your comment inspired me to file that as a feature request on bugzilla for mozilla. So maybe mozilla will have it one day. But as for good email programs that have that now, I don't know, but I'm sure you could find something.
    • Posted at a perfect time actually - lunch break coming up in this neck of the woods:) I quite like the fact that most stories seem to be posted during US day, as it means I can work hard all morning and only get sucked in to /. surfing for the afternoon. It sure increases my productivity level.
  • by mclinc ( 87199 ) on Friday January 04, 2002 @04:10AM (#2783975) Homepage
    Store your mbox (or whatever) on an encrypted file system. Not perfect but easy.
  • by Marijn ( 8405 ) <marijn@sanity.dh ... minus herbivore> on Friday January 04, 2002 @04:20AM (#2783991)
    Really simple, just use an encrypted file-system. Either in a partition or via loopback in a file (convinient for backuping).

    Save, Simple, and you can use any email software you want.
    • Really simple, just use an encrypted file-system.

      What about if the email is on the company's or university's Unix box, where you ssh to run pine on a server on which you can't mount filesystems to any directories? And you still have to keep the mail in one place in order to access it from anywhere. A mail client that'd crypt its archive mboxen would be nice, not that I knew of any :(

      If you're using a personal computer then of course you can use whatever encrypting filesystem/loopback hack you want to. But that's a big "if".

      • What about if the email is on the company's or university's Unix box, where you ssh to run pine

        It doesn't really matter then if you encrypt the files or not, if they really give a toss about your mail then there's many ways of reading it (eg. attaching gdb to your program, having a second xterm pop up whenever you login that shows them exactly what you're doing). Ultimately if you don't trust your admins you're fucked.

    • Does anyone know how to retrieve passwords that have been logged on a macintosh? Any way of getting past keystrokes logged?
    • I second this. I've used The Bat with a PGPdisk setup for a while and it worked like a charm. I had a small script that mounted the filesystem when I started up The Bat (starting it up without an fs has the Bat function sub-optimally to say the least).
      I had it working right on windows but this should be a lot easier to implement on a Linux-like system.

      I discontinued my use because I didn't find it worth my effort. I don't have that much conspirational stuff going on that I have to encrypt my email. And any encrypted email I receive is decrypted for viewing but is still stored in encrypted form so that doesn't need a second level of encryption on top.

      But hey, if you're paranoid, go for it.
  • my setup (Score:3, Interesting)

    by Phork ( 74706 ) on Friday January 04, 2002 @05:46AM (#2784163) Homepage
    a few months back i decided i wanted to setup something similar. i wasnt after an email client that encrypted mailboxes, i wanted an encrypted backup of all email i recived. how i did this was edit my alias file for sendmail to send my mail to a perl script that appends stdin to my mbox, and sends it through a gpg and then to a seperate backup file. so it gets written to 2 places, one unecrypted for immediate viewing, and the other encrypted for long term archiving. if you want my script i can polish it up and send it to you, though you will proably have to modify it at least a little because parts of it are specific to my system.
  • Strange... (Score:2, Informative)

    by fordboy0 ( 547958 )
    I never really gave it a second thought... Thanks for pointing that one out, now I have something else on my plate to worry about!
    But seriously, if you are working on a Winbloze platform, I think that Pegasus stores the mail file in an encryped format - password protected at least - to keep people away. Not for sure on that one, but I will check. May not be heavy enough encryption to keep the Feds off your back, but it should keep the old lady or your less-than-saavy computer friends out. (Or in the case of some, your parents)
    • If you're using Windows you could use PGPDisk, which allows you to create an encrypted 'virtual' volume, in which you could store your e-mail.

      For example, create a 600Mb file called email.pdg using PGPDisk, mount it as X:\ (or whatever) with a password or the passphrase to your public key and copy your e-mail archives into it - maybe into a folder called X:\mail\, then tell your mail client to use the X:\mail\ folder as the mail store.

      Every time you boot you can be prompted for the password and when you unmount the PGPDisk, or shutdown, your data becomes safe.

      I choose a file size of 600Mb so it will fit on a CD without any hassle.
  • I hate to say it, but use lotus notes (if it's possible to get it to sync to a real mail server rather than a notes one). Notes allows you to store encrypted local copies of stuff on your machine, protected by your notes ID and password

    I don't like encouraging people to use notes, but it seems like the answer in this case.

    • True, it is encrypted. And true that the CIA uses Lotus Notes, so it obviously can pass the paranoia test. (Notes is one of the few systems where even mail administrators can't read your email.)

      Where Lotus Notes breaks down in this situation is the certifier IDs. In LN, an administrator uses a "god" (or certifier) ID to create other IDs. That "god" ID can also go back and alter the IDs that it created (like to extend expirations, do name changes for marriage/divorce), which means that forgotten passwords can be unlocked.

      So, using Lotus Notes will keep anyone who's not your boss, and anyone who's not the government, from reading your email.

      There are other encryption keys that the end-user can create in Notes (the ID file can store several encryption keys in it, in different formats, so it's somewhat like a key manager), and they can use these for encryption, but these other keys are used to encrypt fields only, which means you'd have to write something that would take all the fields in your emails, and create new documents in your archive, and encrypt the fields along the way. (Simple, really, and it'd probably take me an afternoon to do.) The on-disk encryption is for the ID only (the one issued from the certifier), which means Bosses and Governments still can get it.

      Oh, but Notes is reasonably stable running under WINE.

      Brings me to one other bit. In the 4.x family of Notes, there were 3 encryption versions. 64-bit (U.S./Canada only, but strangely titled "North American" as if everything north of Panama isn't in North America), 40-bit (International), and this strange French version (unknown encryption, but the French Government didn't want any encryption, really, so it was even lower encryption).

      The U.S. and International versions both used the same 64-bit encryption. However, the U.S. held 24-bits of the 64-bit international key in escrow. That, to me, means that the U.S. could crack 40-bit encryption back in the mid 1990's. In the newest release, the encryption level is higher (128?), and there's only one level for all distributions (I'll exclude France as I really don't know), but that's partly because of eased export laws on encryption, and partly because I think the Feds realize they can get around encryption.

      If you have your own certifiers, and can digitally shred these as the Feds are knocking down your door with a search warrant in hand, then maybe it'd work.
      • If I understand the way the system worked, everyone had 64-bit keys. However the 'international' version always set 24 bits to known values. I use quotes because many companies didn't want to bother tracking two different packages and sold 'international' encryption everywhere.

        This is straightforward because your "password" is not your encryption key. The key is generated by encrypting the password with itself (skipping a *lot* of details) and the ciphertext is the encryption key. It's trivial to add another step that replaces some of these bits with known values. As long as the same password->encryption key algorithm is used the user will never know this happened.

        (It's worth nothing that DES 64-bit keys are actually 56-bits of real key, the rest is parity. I don't know if the 40-bit keys were true 40 bits, or if they were as few as 32-bits of real key.)

        As an aside, you're confusing the geographic and legal definitions of "North America." The US and Canada have very similar cultures since both are former British colonies which absorbed earlier French colonies (Quebue, Louisiana). Mexico and points south, former Spanish colonies, might be on the same side of the equator but have a very different culture.
        • I have a B.A. in Geography, so, yeah, I tend to go for the geographic over the legal definitions.

          Offtopic now, but about ten years ago, the media did one of their famed polls about how little adults know, and one of the results was how few people could name 3 countries in North America.
          (I always love those polls where they ask adults something, then schools are forced to teach kids what the adults didn't know.)

          Back to encryption, I should have added that once the Feds (or whomever has resources) has your Notes ID file, or your GPG/PGP private key file, then brute force attack becomes much easier. Lotus Notes uses PKI, with the ID file holding the private key, and the directory of Notes users holding the public key.

          Having said that, I don't know if it was 56-bit DES, or what, but I do remember the password hash was stored in the ID file, and not the actual password (I think it was the MD5 checksum, but I don't think there was a salt used). I did do a diff on an international vs. a north american version, and only 5 files differed. 2 files each were only in one distribution, and a single DLL had differently named functions in it.
      • "Oh, but Notes is reasonably stable running under WINE."

        I work in a Lotus Notes shop, and the one thing that keeps people from wiping their Microsoft partitions is the lack of a good native Lotus Notes client for Linux. Most of the Lotus guys I know say that the biggest question they get is "When will there be a Notes client for Linux?"

        So, what the answer? Why doesn't Lotus develop a native-Linux Notes client?

        As for the "it works under Wine" point, that's probably true, but our IT weenies don't let us get our hands on the Notes install CDs. Grrr...
        • Well, the version of Notes 5 under Linux I first saw was an RPM that -- the source told me -- was created in IBM by some frustrated users, and contained Note R5 plus a limited part of Wine. (Install the one RPM, and you were gold.)

          I think what's keeping Lotus from going after a Linux version of the client is:

          lack of market share
          limited OLE functionality
          non-unified GUI

          The Lotus Domino server is fully supported on Linux, and you can buy SuSE bundled with the Domino, and SuSE is going to distribute IBM's linux offerings for IBM, so there's potential.

          Slightly off topic, but the other thread on Slashdot right now about LindowsOS shows Lotus Notes running on a Linux box. Mirrored screen capture:

          http://members.rogers.com/kawaichan/1.gif [rogers.com]
        • Many of my coworkers suspect a behind the scenes deal with Microsoft. Now, I know some of you will freak out and start talking about black-helicopter conspiracy theories, but consider: What would happen if Lotus ported a Notes client to Linux? Would this potentially cause people to seriously consider Notes as an Exchange alternative? Would Microsoft care/would it have an effect?

          Consider: How could Microsoft keep the Lotus people from porting and releasing a Notes client for Linux? Could they threaten to withhold APIs and hooks into Windows from Lotus or perhaps even raise the tax...er...licensing fees they charge Lotus/IBM now?
  • I once wrote a patch to mutt [mutt.org] which caused all messages going into sent-mail to be encrypted to myself. It worked, but it became annoying when I wanted to search my sent-mail using an external program, because nothing could read the messages.

    Instead I wrote a little script run from cron which moves my sent-mail to sent-mail-(date) and encrypts the whole thing. This runs once a month. I find it's a good compromise between security and usability.
  • Outlook (Score:4, Informative)

    by Howie ( 4244 ) <howie@thi[ ].com ['ngy' in gap]> on Friday January 04, 2002 @08:40AM (#2784490) Homepage Journal
    Evil nasty bad MS Outlook has had this ability for at least the last few versions (97 onwards I think).

    Depending on how much grief other people reading your mail is going to cause (legal, or merely embarrassing), it's worth noting that several countries already have laws requiring you to give up the keys to your encrypted mail in certain situations, and others are considering similar laws.
  • I am no cryptographer, but one of the issues I have seen with this kind of a system is the fact that you can put fairly easy cribs in the messages themselves that weaken the encryption somewhat. For example, if the system keeps the mail headers, simply send emails with known strings, such as a long X-header, like
    X-crack-this-poor-dope's encryption: SOMEVERYLONGSTRING.
    The odds are, he'll never see it, and now you have a known cleartext string to look for.

    I have got to say, an encrypted fileseystem is probably the best, as at least you don't know where you are supposed to be looking for this string, then.
    • This is only a problem if they're using their own "very special" cryptography, e.g., the ever popular "xor with passphrase and a counter." For some odd reason that's used in several products -- and can be easily cracked with some commercial products.

      If the crypto was done right, the message was compressed and then encrypted in "chaining" mode with DES, 3DES, IDEA, AES, or a similar strong cipher. Having known plaintext won't help much in this case.
  • by scotpurl ( 28825 ) on Friday January 04, 2002 @09:03AM (#2784538)
    If you're worried about something that could be used against you later, why keep it?

    True, I don't like the idea of someone going back through years of email and reading private things. But maybe messages shouldn't be saved by default. And how often do we really go back through our old email for something? Not trolling here, but the majority of email I get isn't worthy of digital immortality.

    At one of the client sites I consulted, they deleted all Inbox mail after 30 days, and had a 3-year maximum retention on everything else in the mail file. (To keep it past 30 days, you basically had to move it to another folder.) Sent mail was also deleted after 90 days, but you could override that, up to the 3 year max. (Contrast that with another site where SEC made them keep _everything_ for years and years.)

    I gotta say, I love it. I've even tweaked my email client to ask me if I want to save a copy, for everything I send.
  • useless (Score:4, Informative)

    by dutky ( 20510 ) on Friday January 04, 2002 @09:52AM (#2784741) Homepage Journal
    Unless the e-mail is encrypted during transmission there is little point in worrying about storing it on your local machine in an encrypted format. Since the transmission format is wide open you have to assume that it has already been captured and read by anyone interested in snooping around your life. If they already have copies of some of the clear text that resides in the encrypted archive, it will be child's play to find your encryption keys and decrypt the entire archive.


    If you are planning on doing stuff you would rather not have extra evidence of later, don't talk about it over e-mail! If you are conspiring with other folk stupid enough to send incriminating information over e-mail, you have bigger problems to worry about. If you are already sending all your e-mail in an encrypted form, you simply need to keep the encrypted e-mails in the archive as well.

    • Re:useless (Score:2, Insightful)

      by Halvard ( 102061 )


      Unless the e-mail is encrypted during transmission there is little point in worrying about storing it on your local machine in an encrypted format.



      Sure, the email should be encrypted during transmission, but there are instances where you are required to keep a paper trail for later reconstruction. A good example is the government. Also, when an organization is actively beefing up security, the fact that they've basically used ignorance in the past as their security protocol, has no bearing on future activity.



      If they already have copies of some of the clear text that resides in the encrypted archive, it will be child's play to find your encryption keys and decrypt the entire archive.



      Too true. Don't send it unencrypted. But that's not part of their information request.


      If you are already sending all your e-mail in an encrypted form, you simply need to keep the encrypted e-mails in the archive as well.



      The problem with this methodology is that if leads a cracker directly to all the "loot". Encrypting everything means they have a lot more work on their hands.

    • Get a grip (Score:4, Insightful)

      by coyote-san ( 38515 ) on Friday January 04, 2002 @10:52AM (#2785042)
      You've been watching too many spy movies...

      The issue most of us face isn't somebody actively snooping into our lives at all times, it's our boss taking a peek around our system to try to find some dirt. Nothing criminal, not even acting in bad faith, but a discussion of how much the VP looked like a drunk duck or a dancing Balmer at a "rally the troops" meeting would do nicely in damaging our image with senior management.

      Of course the boss could ask IT to search the mail archives kept by the company, but then they would have dirt on him! Nope, much better to make a midnight raid and 'accidently' forward the incriminating message to the topic of discussion late some night....
    • Since the transmission format is wide open you have to assume that it has already been captured and read by anyone interested in snooping around your life. If they already have copies of some of the clear text that resides in the encrypted archive, it will be child's play to find your encryption keys and decrypt the entire archive.


      Most modern encryption systems are not vulnerable to "known plaintext attacks". Although DES can be attacked with this it is still not easy. Far from it in fact.

      And if you use a serious system you do not have the same key for each message. Each new mail is encrypted using DES/AES/or similar with a random key which in turn is encrypted with RSA. (This way the program doing the encryption can't be studied to learn the decryption key.) This is what PGP/GPG already do BTW.

      So although that particular mail has been compromised the rest of the archive is safe.

      Next to be secure you need to make sure that your email client / OS is not vulnerable to trojans. If you can't trust your own system you need to use a trusted system to view the messanges. (This is rather theoretical and mainly applicable on public terminals in libraries and internet coffe houses.)

      If you want to be paranoid about it it's far easier for someone with access to listen in on your telephone conversation or use a tele-microphone to listen in when you take a stroll in the park than it is to crack an encrypted transmission.
    • If they already have copies of some of the clear text that resides in the encrypted archive, it will be child's play to find your encryption keys and decrypt the entire archive.

      False. One of the criteria for a strong encryption algorithm is resistance to known plaintext attacks. For symetric key algorithms this means the fastest attack is bruit forcing all of the keys, even if you have an arbitrary ammount of known plaintext. In other words, you cannot recover the key any faster than guess-and-check. For AES with a 256-bit key, this means an average of about 32,000,000,000,000,000,000,000,000,000,000,000,000 ,000,000,000,000,000,000,000,000,000,000,000,000,0 00 tries. All of the world's computers (assuming current trends, and remembering that symetric ciphers are not obviously broken by quantum computation) will not cover this many keys until long after the formaldehide diffuses out of your corpse and soil microbes have devowered all but your coffin.

    • Re:useless (Score:5, Insightful)

      by markj02 ( 544487 ) on Saturday January 05, 2002 @06:04PM (#2791601)
      That's utter BS. There are plenty of reasons you may want to encrypt your E-mail archives even if it's transmitted in plain text. Perhaps you keep them on a laptop and worry about it getting stolen. Perhaps you use a secure VPN for getting your corporate mail and now want to secure the on-disk storage.

      Furthermore, for any reasonable cryptosystem, having even tons of plaintex and encrypted text available is not sufficient to recover the key.

  • mutt (Score:3, Informative)

    by raulmazda ( 87 ) <adam.lazur@org> on Friday January 04, 2002 @10:28AM (#2784915)

    You could pretty easily do this with mutt and the compressed folders patch.

    It allows you to specify a regex for a folder, and then operations for opening and closing. It wouldn't be that much different than using bzip2 or gzip on a folder.

  • IMAP is your friend (Score:2, Interesting)

    by ajrs ( 186276 )

    1. Use IMAP instead of POP; this keeps the mail on the server.


    2. set up an IMAP server on a box that you control, preferably at home. Put the server behind SSL.


    3. When you want to archive an email, drag it over to your home server, and delete the original.


    This assumes that you use an email client that can talk to multiple IMAP servers at once.
  • Try Crypto Heaven (Score:1, Informative)

    by Anonymous Coward
    Try using Cryptoheaven or hush.com
  • PGP Your Archive (Score:2, Interesting)

    by fliplap ( 113705 )
    If you use pine or some other command line client, or really any client you could do this:

    1. Save all your old mail to a file other than the default.

    2. PGP encrypt that file.

    3. It would be pretty simple to write a script to first decrypt the file with a password and then launch your mail reader to read old mail from that file.

    I know its not elegant or the perfect solution but it is much simpler than writing a client todo it. I know a lot of people will be talking about encrypted filesystems. The problem with this, is that your root or user password is usually much shorter than your PGP passkey. The second problem is that not everyone owns the system thier mail is stored on, you have to consider that with systems such as IMAP your mail is stored in TWO places.

    I've never even considered encrypting my old mail, this is a very good idea. Good luck in finding a more elegant solution, and if you do please post it here!
    • Eudora and Netscape conveniently let you choose your mail directory,
      unlike the Microsoft clients. You can save your mail directory on a
      PGP disk (PGPDisk). This worked very well for me for years. You can of
      course do the same thing with any Linux client using volume [sourceforge.net]
      encryption
      (preferably on a single partition -- not root
      -- as small as possible to avoid losing performance).

      But what are you worrying about? They say Linux is invincible...

  • Search out a utility called 'mcrypt'.

    http://mcrypt.hellug.gr/

    "At the time writing this, it supports the algorithms: BLOWFISH, TWOFISH, DES, TripleDES, 3-WAY, SAFER, LOKI97, GOST, RC2, RC6, MARS, IDEA, RIJNDAEL, SERPENT, CAST, ARCFOUR and WAKE."

    then write a wrapper script for your mail client
    to unencrypt the mail folders, run the client, and
    then re-crypt them before exiting.

    works well for me.
  • Use them all and it's on like a pot of grits. PGP4pine is a script that Pine calls (when it sees the PGP encryption header in the mail) PGP4pine then uses GnuPGP (or actually, any of many other encryption programs) to decrypt the message. Everything happens seemlessly (you can even set it up so that PGP4Pine automatically grabs public keys from sig files). Best thing is as far as Pine knows its just text, so the message gets stored encrypted, it's only decrypted when you want to read it or quote it.

    Of course, this assumes you want to use PGP while sending and recieveing messages too (and why wouldn't you..)
  • Don't fiddle around with special E-mail clients, use an encrypted file system.

    If you must, Emacs/XEmacs can be set up to automatically decrypt/encrypt on load/save, and that should work with any of the Emacs/XEmacs mail clients. The packages are crypt.el or jka-compr.

  • The Bat (Score:2, Informative)

    Ritlabs [ritlabs.com] puts out an excellent program called The Bat! and a dongle-secured version called, appropriately enough, Secure Bat! I've been using the bat for about two years now, and have found it to be one of the most stable, secure, and generally well-written pieces of e-mail software I've had the pleasure of using. Secure Bat!, from what I've heard, is every bit as stable, though much more expensive and with features more befitting of administration at a large company. If anyone is left bothering to read this thread anymore, it comes highly recommended (to windows users).

    Of course, you could also just encrypt your old mail file. How often do you go through mail from 1998 anyway?

  • ...to CD periodically. If you really want encryption, tar ball it first and zap that with your favourite crypto.

    Ralf
  • I know that somebody already mentioned CryptoHeaven, but I just want to add more about that... Well, I do somewhat of a confidential research and when I communicate with my team mates, we use email since I travel a lot. We use CryptoHeaven and must tell you, we love it! Basically, you can access your email and your files from anywhere and you know that your data is save cause you hold the keys to unencrypt it. Not only that communication is secure at the first place, I also keep my keys on a disk and always take it with me. I really recommend it. (www.cryptoheaven.com)

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