code: function getSha256Hash (stringToSign, format) {
  	if(!format) {
  		stringToSign = naclInstance.encode_utf8(stringToSign);
  	} else if(format === 'utf8') {
  		stringToSign = naclInstance.encode_utf8(stringToSign);
  	} else if(format === 'hex') {
  		stringToSign = naclInstance.from_hex(stringToSign);
  	}
  
  	return naclInstance.crypto_hash_sha256(stringToSign);
  	// return crypto.createHash('sha256').update(stringToSign, format).digest();
  }
docs: var crypto = require('crypto-browserify'); var convert = require('./convert'); TODO: Discuss behaviour with format and hashing