bintzwing/test/sha256_test_brute_force.js

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2010-05-26 22:34:42 +00:00
/**
* Test SHA-256 using an ad-hoc iterative technique.
* This uses a string buffer which has n characters on the nth iteration.
* Each iteration, the buffer is hashed and the hash is converted to a string.
* The first two characters of the string are prepended to the buffer, then the
* last character of the buffer is removed. This way, neither the beginning nor
* the end of the buffer is fixed.
*
* The hashes from each output step are also hashed together into one final hash.
* This is compared against a final hash which was computed with SSL.
*/
new sjcl.test.TestCase("SHA-256 iterative", function (cb) {
if (!sjcl.hash.sha256) {
this.unimplemented();
cb && cb();
return;
}
var toBeHashed = "", cumulative = new sjcl.hash.sha256(), hash, thiz=this;
browserUtil.cpsIterate(function (i, cbb) {
for (var n=100*i; n<100*(i+1); n++) {
hash = sjcl.hash.sha256.hash(toBeHashed);
hash = sjcl.codec.hex.fromBits(hash);
cumulative.update(hash);
toBeHashed = (hash.substring(0,2)+toBeHashed).substring(0,n+1);
}
cbb && cbb();
}, 0, 10, true, function () {
hash = sjcl.codec.hex.fromBits(cumulative.finalize());
thiz.require(hash === "f305c76d5d457ddf04f1927166f5e13429407049a5c5f29021916321fcdcd8b4");
cb && cb();
});
});