Hi ziggi,
Something like this to parse this ASN.1 value:
byte[] data =
Hex.DecodeStrict("04133011020100310C130141130143130149130150");
Asn1Object obj = Asn1Object.FromByteArray(data);
Asn1OctetString oct = Asn1OctetString.GetInstance(obj);
Asn1Sequence seq = Asn1Sequence.GetInstance(oct.GetOctets());
DerInteger num = DerInteger.GetInstance(seq[0]);
Asn1Set set = Asn1Set.GetInstance(seq[1]);
foreach (Asn1Encodable e in set)
{
DerPrintableString str = DerPrintableString.GetInstance(e);
Console.WriteLine(str.GetString());
}
However generally you will need to check the actual ASN.1 syntax
definition; there could be optional fields or other variations that a
parser for this type would need to handle.
Regards,
Pete Dettman
On 24/6/20 5:34 pm, ziggi slaw wrote:
> Consider this input: 04133011020100310C130141130143130149130150
>
> It is a DerOctetString, with length of 13h and a value. The value itself
> is also an ASN.1 structure:
> 30 11
> 02 01 00
> 31 0C
> 13 01 41
> 13 01 43
> 13 01 49
> 13 01 50
>
> How can I get the 'final' PrintableString values, in this case 41, 43,
> 49 and 50?
>
> I guess first I have to convert input byte array to DerOctetString....
> This is easy, 'var s = new DerOctetString(input);'. Then I should
> probably do something like this:
> - get the value from the DerOctetString
> - generate new DerSequence from the value
> - get the DerSet from the DerSequence
> - get all PrintableString values from the sequence.
>
> I stumble right at the beginning - how to you even get the value of of
> the DerOctetString? ToString method returns tag, length and value.
> GetOctets method returns all bytes, including tag and length, ...
> Off course I could use offset (read from index 3 onwards), but there's
> probably a more idiomatic way to do it Could anyone help with an example?
>
> Thanks!
