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

test/genHashRounds.py

A Python2 script that generates multi-round hash values

build/make-release

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

build/externs.js

File needed solely to make the Google Closure Compilter work

Usage

Browser

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>

Hashing

Instantiate a new jsSHA object with the desired hash type, input type, and options as parameters. The hash type can be one of SHA-1, SHA-224, SHA-256, SHA-384, or SHA-512. The input type can be one of HEX, TEXT, B64, or BYTES. You can then stream in input using the "update" object function. Finally, simply call "getHash" with the output type as a parameter (B64, HEX, or BYTES). Example to calculate the SHA-512 of "This is a test":

var shaObj = new jsSHA("SHA-512", "TEXT");
shaObj.update("This is a test");
var hash = shaObj.getHash("HEX");

The constructor takes a hashmap as a optional third argument with possible properties of "numRounds" and "encoding". numRounds controls the number of hashing iterations/rounds performed and defaults to a value of "1" if not specified. encoding specifies the encoding used to encode TEXT-type inputs. Valid options are "UTF8", "UTF16BE", and "UTF16LE", it defaults to "UTF8".

getHash also takes a hashmap as an optional second argument. By default the hashmap is {"outputUpper" : false, "b64Pad" : "="}. These options are intelligently interpreted based upon the chosen output format.

HMAC

Instantiate a new jsSHA object the same way as for hashing. Then set the HMAC key to be used by calling "setHMACKey" with the key and its input type (this MUST be done before calling update). You can stream in the input using the "update" object function just like hashing. Finally, get the HMAC by calling the "getHMAC" function with the output type as its argument. Example to calculate the SHA-512 HMAC of the string "This is a test" with the key "abc":

var shaObj = new jsSHA(hashType, "TEXT");
shaObj.setHMACKey("abc", "TEXT");
shaObj.update("This is a test");
var hmac = shaObj.getHMAC("HEX");

setHMACKey takes the same input types as the constructor and getHMAC takes the same inputs as "getHash" as described above.

Note: You cannot calculate both the hash and HMAC using the same object.

Node.js

jsSHA is available through NPM and be installed by simply doing

npm install jssha

To use the module, first require it using:

jsSHA = require("jssha");

The rest of the instructions are identical to the Browser section above.

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>" \
	--externs /path/to/build/externs.js --warning_level VERBOSE \
	--compilation_level ADVANCED_OPTIMIZATIONS \
	--js /path/to/sha_dev.js --js_output_file /path/to/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/