jsSHA - A JavaScript implementation of the complete Secure Hash Standard family
		(SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512) as well as HMAC by
		Brian Turek

About
-------------------------
jsSHA is a javaScript implementation of the complete Secure Hash Algorithm
family as defined by FIPS PUB 180-2
(http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdf).
It also includes the HMAC algorithm with SHA support as defined by FIPS PUB 198-1
(http://csrc.nist.gov/publications/fips/fips198-1/FIPS-198-1_final.pdf)

With the slow phasing out of MD5 as the standard hash to use in web
applications, a client-side implementation of the complete Secure Hash Standard
family was needed.  Due to SHA-384 and SHA-512's use of 64-bit values throughout
the algorithm, JavaScript can not easily natively support the calculation of
these hashes.  As a result, a bit of hacking had to be done to make sure the
values behaved themselves. SHA-224 was added to the Secure Hash Standard family
on 25 February 2004 so it was also included in this package.

Files
-------------------------
src/sha_dev.js
A commented implementation of the entire SHA family of hashes. Not to be used
in production.

src/sha.js
A Google Closure Compiler optimized version of the entire library

src/sha1.js
A Google Closure Compiler optimized version the library with non SHA-1
functionality removed

src/sha256.js
A Google Closure Compiler optimized version the library with non SHA-224/SHA-256
functionality removed

src/sha512.js
A Google Closure Compiler optimized version the library with non SHA-384/SHA-512
functionality removed

test/test.html
A test page that calculates various hashes and has their correct values

build/make-release
A Bash script that runs the various Google Closure Compiler commands to build
a release

Usage
-------------------------
Include the desired JavaScript file (sha.js, sha1.js, sha256.js, or sha512.js)
in your header (sha.js used below):
<script type="text/javascript" src="/path/to/sha.js"></script>

Instantiate a new jsSHA object with your string to be hashed and its format
(HEX or TEXT) as the parameters.  Then, call getHash with the desired hash
variant (SHA-1, SHA-224, SHA-256, SHA-384, or SHA-512) and output type
(HEX or B64).  In the example below, "This is a Test" and "SHA-512" were used
as the string to be hashed and variant respectively.  Also, the HMAC using TEXT
key "SecretKey" and hashing algorithm SHA-512 was calculated.

var shaObj = new jsSHA("This is a Test", "TEXT");
var hash = shaObj.getHash("SHA-512", "HEX");
var hmac = shaObj.getHMAC("SecretKey", "TEXT", "SHA-512", "HEX");

The constructor takes an optional parameter, charSize, that specifies the
bit width of a character of text. By default, charSize = 8.

Both getHash and getHMAC also take an optional has list parameter,
outputFormatOpts, that dictates some formatting options for the output.  By
default, outputFormatOpts = {"outputUpper" : false, "b64Pad" : "="}.  These
options are intelligently interpreted based upon the chosen output format.

Compiling
-------------------------
This library makes use of the Google Closure Compiler
(https://developers.google.com/closure/compiler) to both boost performance
and reduce filesizes.  To compile sha_dev.js into a customized output file, use
a command like the following:

	java -jar compiler.jar --define="SUPPORTED_ALGS=<FLAG>"
		--output_wrapper "(function() {%output%})();" --warning_level VERBOSE
		--compilation_level ADVANCED_OPTIMIZATIONS --js sha_dev.js --js_output_file sha.js
		
where <FLAG> is a bitwise OR of the following values:
  - 4 for SHA-384/SHA-512
  - 2 for SHA-224/256
  - 1 for SHA-1

Contact Info
-------------------------
The project's website is located at http://caligatio.github.com/jsSHA/