Looking for a nice ASN.1 stack

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I am working on GSM/SS7 protocol implementation on and off for a bit. The current modules can be found in these git repositories.

Right now I am working on parsing and creating ISDN User Part (ISUP) messages and the general question of how to express on-wire messages composed from mandantory, variable and optional fields (class based vs. instance based). For now I am using a class based approach as this allows me to have field decoding/encoding inside these classes but I am not sure if this is the best way and will keep on exploring it.

After having finished the ISUP part I will move to the Transaction Capabilities Application Part (TCAP), Mobile Application Part (MAP) and Camel Application Part (CAP). All these protocols specify the messages in ASN.1 and use the Basic Encoding Rules (BER). The biggest obstacle is the lack of a ASN.1 stack. The LDAP code on SqueakSource has some basic (too basic) ASN.1 support, I have seen that VisualWorks has ASN.1 support as well but the code does not seem to be under a OpenSource license.

Does anyone know a freely available ASN.1 implementation that supports DER encoding and BER decoding? Any hints would be welcome.

The semantix company did some:
http://semantix.gr/assert/
http://semantix.gr/asn1scc/

Denis (GNUtoo).

Have you looked at GNU Libtasn? It is fairly small. I don't know what your requirements are, but let us know if there is something missing that you need...

/Simon

Hi Holger,

I not sure about the availability of a Smalltalk ASN.1 compiler or runtime library with a open source license (plus proper encodings). I am afraid to say this, but maybe have a look at the freely available ASN.1 compilers and runtime libraries (in Java or C/C++) and do it from scratch...

If so, then jump to

"Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)"

   http://www.itu.int/itu-t/x.690

Cheers,

Artur

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