Hi,
thats fine. i would say, To decode a content, you must be knowing the ASN.1
definition of that.
i just explain my thoughts.
stage : 1. ASN.1 definition file
stage : 2 Parse that file. ( Parser will do that, it should check the
Integrity / syntax / notation of that file ).
should check whether it satifies the ASN.1 definition
rule. ( ISO-8824 )
[ ur note.1 will not work anymore ]
stage : 3 Generate corresponding definitions in any High level
languages( C / C++ / Java..)
Called as 'Abstract syntax' of that definition.
stage : 4. You can set values to It.
stage : 5 apply the BER rule on it. ( ISO-8825 ).
Called as 'transfer syntax'.
stage : 6 u will get 'Encoded contents'. can be Binary / ascii / octets
formats.
stage : 7 If u apply decoding rule on it, u will get 'Original values'.
Are u want it in Java / C ?
-salai
----- Original Message -----
From: "SADANAMI Keishi" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Saturday, December 22, 2001 12:39 AM
Subject: [ASN.1] Reverse Engineering
> Hello all,
>
> I'm a bioinformatics student currently creating small in-house
> protein-ligand database. I'm very new to ASN, (started a few days
> ago) and facing practical problems with it right now.
>
> I have to extract information from ASCII-encoded ASN.1 datafile
> which I have received from a certain obsolete biological database.
> Unfortunately, I couldn't get any ASN.1 specification of this database,
> though I had tried every possible means. So I'm considering
> reverse-engineer ASN.1 definition from the ASCII-decoded ASN.1 data.
>
> 1) I assume I can accomplish this by trial and error: First presume
> certain ASN.1 definition, judging from instances of the database, then
> make a parser. If the parsing fails, modify previous definition, create
> a new parser, and so on. Are there better ways to automate these tasks?
> The number of instances in this database is about 50,000.
>
> 2) There seems to be many ASN.1 compilers which can encode/decode data
> as a binary stream like BER, but I couldn't find ASCII decoder(parser).
> Is it just a matter of using tools like yacc when it comes to decoding
> *ASCII* data of ASN.1, or are there any such tools publicly available
> on the web? (so that I would rather not re-invent the wheel.)
>
> Sorry if these questions aren't appropriate for this list.
>
> Regards,
>
> Keishi
>
