I was wondering if in a subsequent PR it would be useful to change the function signature.  Unclear original intent and didn't want to put too much in this patch.

Brian J Brennan <notifications@github.com> wrote:
>> @@ -12,7 +12,7 @@ var HASH_ALGS = {
>>    "sha256": function(message) {return
>libs.sjcl.codec.hex.fromBits(libs.sjcl.hash.sha256.hash(message));}
>>  };
>>  
>> -function doHash(hashAlg, message, modulus) {
>> +function doHash(hashAlg, message /*, modulus */) {
>
>Would it be better to remove the `modulus` argument entirely instead of
>commenting out if it's not going to be used?
>
>---
>Reply to this email directly or view it on GitHub:
>https://github.com/mozilla/jwcrypto/pull/71/files#r7284061

lloyd - (on an tiny keyboard)