Some KeyAlgorithms have readonly attributes others don't. These ones for instance don't:


interface RsaKeyAlgorithm : KeyAlgorithm {
  // The length, in bits, of the RSA modulus
  unsigned long modulusLength;
  // The RSA public exponent
  BigInteger publicExponent;
};

dictionary HmacKeyAlgorithm : KeyAlgorithm {
  // The inner hash function to use.
  KeyAlgorithm hash;
};
    

It be confusing to allow mutating these properties, since it shouldn't have an effect on the key. Hence I recommend making them readonly.