Cryptkit is a Tcl binding to the Cryptlib security toolkit.

From the Cryptlib web site - "The Cryptlib security toolkit is a powerful security toolkit that allows even inexperienced crypto programmers to easily add encryption and authentication services to their software. The high-level interface provides anyone with the ability to add strong security capabilities to an application in as little as half an hour, without needing to know any of the low-level details that make the encryption or authentication work. Because of this, cryptlib dramatically reduces the cost involved in adding security to new or existing applications." [http://www.cs.auckland.ac.nz/~pgut001/cryptlib]

Cryptkit brings these benefits to Tcl.

This first release provides an API that closely matches the Cryptlib C API (to remain consistent with the existing documentation). The next release will have a more "Tclish" API.

Downloads
   * the Cryptkit README [http://www.digitalsmarties.com/cryptkit/README]
   * a Starkit containing a pre-built Cryptkit package for Linux-x86, Mac OSX and Sharp Zaurus (Linux-ARM)  [http://www.digitalsmarties.com/cryptkit/cryptkit.kit] - builds for other platforms will follow soon (Windows, Pocket PC)
   * the Cryptkit source [http://www.digitalsmarties.com/cryptkit/cryptkit.tar.gz]
   * some test scripts at [http://www.digitalsmarties.com/cryptkit/tests] also demonstrate the use of Cryptkit from Tcl  

Cryptkit was written by Steve Landers [mailto:steve@DigitalSmarties.com] and was made possible through the financial support of [Eolas] Technologies Inc. Cryptkit is distributed under a Tcl BSD style license, as documented in
the license.terms file in the distribution.

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[MDD]: Great job Steve!
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Example - test cipher

 proc testCipher {cryptAlgo keySize algoName} {
    # Create context with random IV (if it needs one) and a key derived
    # from a password using a salt and iteration count to hinder guessing
    # attacks
    cryptCreateContext encContext CRYPT_UNUSED $cryptAlgo
    cryptSetAttribute $encContext CRYPT_CTXINFO_KEYSIZE $keySize
    cryptSetAttribute $encContext CRYPT_CTXINFO_KEYING_ITERATIONS 10000
    cryptSetAttributeString $encContext CRYPT_CTXINFO_KEYING_SALT "salt1234"
    cryptSetAttributeString $encContext CRYPT_CTXINFO_KEYING_VALUE "password123"
        
    # Encrypt 10 MB of text     
    set text [binary format a[expr {10 * 1024 * 1024}] \0]
    set startTime [clock seconds]
    cryptEncrypt $encContext $text
    set endTime [clock seconds]
    puts "$cryptAlgo 10 Mb in [expr {$endTime - $startTime}] seconds"
    
    cryptDestroyContext $encContext
 }   

 cryptInit
 cryptAddRandom NULL CRYPT_RANDOM_SLOWPOLL
 testCipher CRYPT_ALGO_HMAC_SHA 32 "HMAC-SHA1   Processed"
 testCipher CRYPT_ALGO_RC4      16 "RC4         Encrypted"
 testCipher CRYPT_ALGO_AES      16 "AES-128 CBC Encrypted"
 testCipher CRYPT_ALGO_AES      32 "AES-256 CBC Encrypted"
 testCipher CRYPT_ALGO_3DES     24 "3DES CBC    Encrypted"
 cryptEnd

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'''Implementation'''

Cryptkit is implemented using [Critcl] and uses the new '''critcl::cdefines''' feature that maps C #defines and enums into a Tcl namespace. 

For example, cryptkit.tcl uses the following to map Cryptlib symbols (i.e. #defines and enums) into the cryptkit namespace

    # map Cryptlib #defines and enums into the current namespace
    critcl::cdefines CRYPT_* [namespace current]

    # other defines
    critcl::cdefines {
        NULL
        TRUE
        FALSE
        TCL_OK
        TCL_ERROR
    } [namespace current]

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'''Acknowledgements'''

* [Michael Doyle] for the idea of a Cryptlib binding for Tcl
* [Jeff Hobbs] for his help in reviewing the generated C code
* [Steve Redler IV] for providing access to his Sharp Zaurus and helping with the Cryptkit port