X509 name with specified encoding

[microshine]

For some cases, we need to determine what encoding we should use for name creation. I'd like to discuss here and decide how we could extend the Name class to support this feature

The current implementation uses harden coded logic and doesn't allow doing it dynamically. IA5String encoding is used for E and DC names, and PrintableString or UTF8String encoding depends on incoming string.

if (type === this.getName("E") || type === this.getName("DC")) {
  attr.value.ia5String = value;
} else {
  // Use Utf8String for non ASCII strings
  if (Name.isASCII(value)) {
    attr.value.printableString = value;
  } else {
    attr.value.utf8String = value;
  }
}

[microshine]

I've got 3 ideas how we could do it

1. To use type prefixes for string representation of distinguished names

it doesn't match RFC2253, but allows specifying any encoding for any attribute

const name = new Name("CN=p:Some name, O=u8:Home");

where prefixes are:

t  TeletexString
p  PrintableString
u  UniversalString
u8 UTF8String
b  BMPString

3. To use encoding profile for Name creation

It doesn't allow specifying multiple encoding for one attribute type (eg CN=p:Test, CN=u8:Value)

const name = new Name("CN=Some name, O=Home", {
  CN: NameEncoding.PrintableString,
  O: NameEncoding.UTF8String,
});

5. To extend and improve JsonName

const name = new x509.Name([
  {
    CN: [
      {
        printableString: "Some name",
      },
    ]
  },
  {
    O: [
      {
        utfString: "Home",
      },
    ]
  },
]);

[turon]

Per discussion in #25, my vote would be option 5 (the last of the three proposals).
The JSON API is generally provided for lower level control, so seems like an appropriate place to add options for specifying specific string encoding.

[turon]

Also, on option 1, wouldn't a more "typescript" style be: const name = new Name("CN:p=Some name, O:u8=Home");?

[microshine]

const name = new Name("CN:p=Some name, O:u8=Home");

Looks good. This format doesn't require escaping ':' char in names