What I need is to ensure that a string gets encoded in a known character encoding. So far, my research and testing with MS SQL Server has revealed that the documented encoding is 'UCS-2', however the actual encoding (on the server in question) is 'UCS-2LE'.
Which doesn't seem very reliable. What I would love is an ENCODE function as found in PERL, Node, or most anything, so that regardless of upgrades or settings changes, my hash function will be working on known input.
We can limit the hashing string to HEX, so at worst, we could manually map the 16 possible input characters to the proper bytes. Anyone have a recommendation on this?
Here's the PERL I'm using:
use Digest::SHA qw/sha256/;
use Encode qw/encode/;
$seed = 'DDFF5D36-F14D-495D-BAA6-3688786D6CFA';
$string = '123456789';
$target = '57392CD6A5192B6185C5999EB23D240BB7CEFD26E377D904F6FEF262ED176F97';
$encoded = encode('UCS-2LE', $seed.$string);
$sha256 = uc(unpack("H*", sha256($encoded)));
print "$target\n$sha256\n";
Which matches MS SQL:
HASHBYTES('SHA_256', 'DDFF5D36-F14D-495D-BAA6-3688786D6CFA123456789')
But what I really want is:
HASHBYTES('SHA_256', ENCODE('UCS2-LE', 'DDFF5D36-F14D-495D-BAA6-3688786D6CFA123456789'))
So that no matter what MS SQL happens to be encoding the input string as, the HASHBYTES will always operate on a known byte array.