This version of Cryptol is (C) 2013-2014 Galois, Inc., and
distributed under a standard, three-clause BSD license. Please see
the file LICENSE, distributed with this software, for specific
terms and conditions.
The Cryptol specification language was designed by Galois for the NSA's Trusted Systems Research Group as a public standard for specifying cryptographic algorithms. A Cryptol reference specification can serve as the formal documentation for a cryptographic module. Unlike current specification mechanisms, Cryptol is fully executable, allowing designers to experiment with their programs incrementally as their designs evolve.
This release is an interpreter for version 2 of the Cryptol
language. The interpreter includes a :check
command, which tests
predicates written in Cryptol against randomly-generated test vectors
(in the style of
QuickCheck. There is
also a :prove
command, which calls out to SMT solvers, such as
Yices, Z3, or CVC4, to prove predicates for all possible inputs.
Cryptol binaries for Mac OS X, Linux, and Windows are available from
the GitHub
releases page. Mac OS
X and Linux binaries are distributed as a tarball which you can
extract to a location of your choice. Windows binaries are distributed
as an .msi
installer package which places a shortcut to the Cryptol
interpreter in the Start menu.
Cryptol currently depends on the
CVC4 SMT solver to solve constraints during
type checking, and as the default solver for the :sat
and :prove
commands. You can download CVC4 binaries for a variety of platforms
from their download page.
In addition to the binaries, the Cryptol source is available publicly on GitHub.
Cryptol builds and runs on various flavors of Linux, Mac OS X, and Windows. We regularly build and test it in the following environments:
- Mac OS X 10.9 64-bit
- CentOS 5 32/64-bit
- CentOS 6 32/64-bit
- Windows XP 32-bit
Cryptol is developed using GHC 7.6.3 and cabal-install 1.18. While you can install these independently, the easiest way to get the correct versions is to:
-
Install Haskell Platform 2013.2.0.0
Mac Users: the current version of the Haskell Platform has some incompatibilities with Mac OS X 10.9; it is easier to install GHC, cabal-install, alex, and happy from MacPorts or Homebrew.
-
Run
cabal update
-
Run
cabal install cabal-install
-
Add cabal-install's binary path to your
PATH
variable (usually~/.cabal/bin
)
Some supporting non-Haskell libraries are required to build Cryptol. Most should already be present for your operating system, but you may need to install the following:
You'll also need CVC4 installed when running Cryptol.
From the Cryptol source directory, run:
make
This will build Cryptol in place. From there, there are additional targets:
make test
: run the regression test suite (note: 4 failures is expected)make docs
: build the Cryptol documentation (requires pandoc and TeX Live)make tarball
: build a tarball with a relocatable Cryptol binary and documentationmake dist
: build a platform-specific distribution. On all platforms except Windows, this is currently equivalent tomake tarball
. On Windows, this will build an.msi
package using WiX Toolset 3.7, which must be installed separately.
Aside from the docs
target, these will leave you with a Cryptol
binary at .cabal-sandbox/bin/cryptol
in your source directory. You
can either use that binary directly, or use the results of tarball
or dist
to install Cryptol in a location of your choice.
Run Cryptol, and at the prompt type:
Cryptol> :prove True
If Cryptol responds
Q.E.D.
then Cryptol is installed correctly. If it prints something like
*** An error occurred.
*** Unable to locate executable for cvc4
*** Executable specified: "cvc4"
then make sure you've installed CVC4, and that the
binary is on your PATH
.
As noted above, make test
currently results in four failures. An issue has been filed on GitHub for each of them.
We believe that anyone who uses Cryptol is making an important contribution toward making Cryptol a better tool. There are many ways to get involved.
If you write Cryptol programs that you think would benefit the
community, fork the GitHub repository, and add them to the
examples/contrib
directory and submit a pull request.
We host a Cryptol mailing list, which you can join here.
If you run into a bug in Cryptol, if something doesn't make sense in the documentation, if you think something could be better, or if you just have a cool use of Cryptol that you'd like to share with us, use the issues page on GitHub, or send email to [email protected].
If you plan to do development work on the Cryptol interpreter, please make a fork of the GitHub repository and send along pull requests. This makes it easier for us to track development and to incorporate your changes.
/cryptol
: Haskell sources for the front-endcryptol
executable and read-eval-print loop/docs
: LaTeX and Markdown sources for the Cryptol documentation/examples
: Cryptol sources implementing several interesting algorithms/lib
: Cryptol standard library sources/notebook
: Experimental Cryptol IPython Notebook implementation/sbv
: Haskell sources for thesbv
library, derived from Levent Erkok'ssbv
library (see/sbv/LICENSE
)/src
: Haskell sources for thecryptol
library (the bulk of the implementation)/tests
: Haskell sources for the Cryptol regression test suite, as well as the Cryptol sources and expected outputs that comprise that suite
The docs
directory of the installation package contains an
introductory book, the examples
directory contains a number of
algorithms specified in Cryptol.
If you are familiar with version 1 of Cryptol, you should read the
Version2Changes
document in the docs
directory.
Cryptol is still under active development at Galois. We are also building tools that consume both Cryptol specifications and implementations in (for example) C or Java, and can (with some amount of work) allow you to verify that an implementation meets its specification. Email us at [email protected] if you're interested in these capabilities.
We hope that Cryptol is useful as a tool for educators and students, commercial and open source authors of cryptographic implementations, and by cryptographers to
- specify cryptographic algorithms
- check or prove properties of algorithms
- generate test vectors for testing implementations
- experiment with new algorithms
Cryptol has been under development for over a decade with many people contributing to its design and implementation. Those people include (but are not limited to) Iavor Diatchki, Aaron Tomb, Adam Wick, Brian Huffman, Dylan McNamee, Joe Kiniry, John Launchbury, Matt Sottile, Adam Foltzer, Joe Hendrix, Trevor Elliott, Lee Pike, Mark Tullsen, Levent Erkök, David Lazar, Joel Stanley, Jeff Lewis, Andy Gill, Edward Yang, Ledah Casburn, Jim Teisher, Sigbjørn Finne, Mark Shields, Philip Weaver, Magnus Carlsson, Fergus Henderson, Joe Hurd, Thomas Nordin, John Matthews and Sally Browning. In addition, much of the work on Cryptol has been funded by, and lots of design input was provided by the team at the NSA's Trusted Systems Research Group, including Brad Martin, Frank Taylor and Sean Weaver.