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Cyphernomicon 7.11

PGP -- Pretty Good Privacy:
Other Crypto Programs And Tools


   7.11.1. Other Ciphers and Tools
           - RIPEM
           - PEM
           - MD5
           + SFS (Secure FileSystem) 1.0
             - "SFS (Secure FileSystem) is a set of programs which
                create and manage a number of encrypted disk volumes, and
                runs under both DOS and Windows.  Each volume appears as
                a normal DOS drive, but all data stored on it is encryped
                at the individual-sector level....SFS 1.1 is a
                maintenance release which fixes a few minor problems in
                1.0, and adds a number of features suggested by users.
                More details on changes are given in in the README file."
                [Peter Gutmann, sci.crypt, 1994-08-25]
             - not the same thing as CFS!
             - 512-bit key using a MDC/SHS hash. (Fast)
             - only works on a386 or better (says V. Bontchev)
             - source code not available?
             - implemented as a device driver (rather than a TSR, like
                SecureDrive)
             - "is vulnerable to a special form of attack, which was
                mentioned once here in sci.crypt and is described in
                detaills in the SFS documentation. Take a loot at the
                section "Encryption Considerations"." [Vesselin Bontchev,
                sci.crypt, 1994-07-01]
             - Comparing SFS to SecureDrive: "Both packages are
                approximately equal in terms of user interface, but SFS
                seems to be quite a bit faster.  And comments from
                various people (previous message thread) seems to
                indicate that it is more "secure" as well." [Bill Couture
                <coutu001@gold.tc.umn.edu> , sci.crypt, 1994-0703]
           + SecureDrive
             - encrypts a disk (always be very careful!)
             - SecureDrive 1.3D, 128-bit IDEA cypher is based on an MD5
                hash of the passphrase
             - implemented as a TSR (rather than a device driver, like
                CFS)
             - source code available
             + Some problems reported (your mileage may vary)
               - "I have been having quite a bit of difficulty with my
                  encrypted drive mangling files. After getting secure
                  drive 1.3d installed on my hard drive, I find that
                  various files are being corrupted and many times after
                  accessing the drive a bunch of crosslinked files are
                  present." [Vaccinia@uncvx1.oit.unc.edu, 1994-07-01]
             - Others report being happy with, under both DOS and
                Windows
             - no OS/2 or Mac versions reported; some say an OS/2 device
                driver will have to be used (such as Stacker for OS/2
                uses)
           + SecureDevice
             - "If you can't find it elsewhere, I have it at
                ftp://ftp.ee.und.ac.za/pub/crypto/secdev13.arj, but
                that's at the end of a saturated 64kbps link." [Alan
                Barrett, 1994-07-01]
   7.11.2. MDC and SHS (same as SHA?)
           - "The MDC cyphers are believed to be as strong as it is
              difficult to invert the cryptographic hash function they
              are using. SHS was designed by the NSA and is believed to
              be secure. There might be other ways to attack the MDC
              cyphers, but nobody who is allowed to speak knows such
              methods."  [Vesselin Bontchev, sci.crypt, 1994-07-01]
           + Secure Hash Standard's algorithm is public, and hence can
              be analyzed and tested for weaknesses (in strong contrast
              with Skipjack).
             - may replace MD5 in future versions of PGP (a rumor)
           - Speed of MDC: "It's a speed tradeoff.  MDC is a few times
              faster than IDEA, so SFS is a few times faster than
              SecureDrive.  But MDC is less proven." [Colin Plumb,
              sci.crypt, 1994-07-04]
           + Rumors of problems with SHA
             - "The other big news is a security problem with the Secure
                Hash Algorithm (SHA), discussed in the Apr 94 DDJ.  The
                cryptographers at NSA have found a problem with the
                algorithm.  They won't tell anyone what it is, or even
                how serious it is, but they promise a fix soon.  Everyone
                is waiting with baited breath." [Bruce Schneier, reprot
                on Eurocrypt '94, 1994-07-01]
   7.11.3. Stego programs
           + DOS
             - S-Tools (or Stools?). DOS? Encrypts in .gif and .wav
                (SoundBlaster format) files. Can set to not indicate
                encrypted files are inside.
           - Windows
           + Macintosh
             - Stego
             + sound programs
               - marielsn@Hawaii.Edu (Nathan Mariels) has written a
                  program which "takes a file and encrypts it with IDEA
                  using a MD5 hash of the password typed in by the user.
                  It then stores the file in the lowest bit (or bits,
                  user selectable) of a sound file."
   7.11.4. "What about "Pretty Good Voice Privacy" or "Voice PGP" and
            Other Speech Programs?"
           + Several groups, including one led by Phil Zimmermann, are
              said to be working on something like this. Most are using
              commercially- and widely-available sound input boards, a la
              "SoundBlaster" boards.
             - proprietary hardware or DSPs is often a lose, as people
                won't be able to easily acquire the hardware; a software-
                only solution (possibly relying on built-in hardware, or
                readily-available add-in boards, like SoundBlasters) is
                preferable.
           + Many important reasons to do such a project:
             - proliferate more crypto tools and systems
             - get it out ahead of "Digital Telephony II" and Clipper-
                type systems; make the tools so ubiquitous that outlawing
                them is too difficult
             - people understand voice communcations in a more natural
                way than e-,mail, so people who don't use PGP may
                nevertheless use a voice encryption system
           + Eric Blossom has his own effort, and has demonstrated
              hardware at Cypherpunks meetings:
             - "At this moment our primary efforts are on developing a
                family of extensible protocols for both encryption and
                voice across point to point links.  We indend to use
                existing standards where ever possible.
                
                "We are currently planning on building on top of the RFCs
                for PPP (see RFCs 1549, 1548, and 1334).  The basic idea
                is to add a new Link Control Protocol (or possibly a
                Network Control Protocol) that will negotiate base and
                modulus and perform DH key exchange.  Some forms of
                Authentication are already supported by RFCs.  We're
                looking at others." [Eric Blossom, 1994-04-14]
           + Building on top of multimedia capabilities of Macintoshes
              and Windows may be an easier approach
             - nearly all Macs and Windows machines will be
                multimedia/audiovisual-capable soon
             - "I realize that it is quite possible to design a secure
                phone
                with a Vocoder, a modem and some cpu power to do the
                encryption, but I think that an easier solution may be on
                the horizon. ....I believe that Microsoft and many others
                are exploring hooking phones to PCs so people can do
                things like ship pictures of their weekend fun to
                friends. When PC's can easily access phone
                communications, then developing encrypted conversations
                should be as easy as programming for Windows :-)."
                [Peter Wayner, 1993--07-08]
   7.11.5. Random Number Generators
           - A huge area...
           + Chaotic systems, pendula
             - may be unexpected periodicities (phase space maps show
                basins of attraction, even though behavior is seemingly
                random)
   7.11.6. "What's the situation on the dispute between NIST and RSADSI
            over the DSS?"
           - NIST claims it doesn't infringe patents
           - RSADSI bought the Schnorr patent and claims DSS infringes
              it
           - NIST makes no guarantees, nor does it indemnify users
              [Reginald Braithwaite-Lee, talk.politics.crypto, 1994-07-
              04]
   7.11.7. "Are there any programs like telnet or "talk" that use pgp?"
           - "Don't know about Telnet, but I'd like to see "talk"
              secured like that...  It exists. (PGP-ized ytalk, that is.)
              Have a look at ftp.informatik.uni-
              hamburg.de:/pub/virus/crypto/pgp/tools/pgptalk.2.0.tar.gz"
              [Vesselin Bontchev, alt.security.pgp, 1994-07-4]
   7.11.8. Digital Timestamping
           + There are two flavors:
             - toy or play versions
             - real or comercial version(s)
           + For a play version, send a message to
              "timestamp@lorax.mv.com" and it will be timestamped and
              returned. Clearly this is not proof of much, has not been
              tested in court, and relies solely on the reputation of the
              timestamper. (A fatal flaw: is trivial to reset system
              clocks on computes and thereby alter dates.)
             - "hearsay" equivalent: time stamps by servers that are
                *not* using the "widely witnessed event" approach of
                Haber and Stornetta
           - The version of Haber and Stornetta is of course much more
              impressive, as it relies on something more powerful than
              mere trust that they have set the system clocks on their
              computers correctly!
 

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