Browse Prior Art Database

Open Systems Interconnection Presentation Protocol Data Unit Decoder

IP.com Disclosure Number: IPCOM000115690D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 75K

Publishing Venue

IBM

Related People

Neffenger, J: AUTHOR

Abstract

A program is disclosed that decodes Open Systems Interconnection (OSI) Presentation Protocol Data Units (PPDUs), or any sequence of values within them, using International Organization for Standardization (ISO) 8825, "Specification of Basic Encoding Rules for Abstract Syntax Notation One (ASN.1)."

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Open Systems Interconnection Presentation Protocol Data Unit Decoder

      A program is disclosed that decodes Open Systems
Interconnection (OSI) Presentation Protocol Data Units (PPDUs), or
any sequence of values within them, using International Organization
for Standardization (ISO) 8825, "Specification of Basic Encoding
Rules for Abstract Syntax Notation One (ASN.1)."

      The input to the program is a string of hexadecimal digits,
with or without intervening blanks or blank lines.

      For each individual encoding, the program shows to the right of
its hexadecimal value the following information:
  o  its offset in the PPDU
  o  its ASN.1 tag value
  o  its ASN.1 type (if known) and
  o  its content length in bytes.

      The program uses indentation to show the nesting of constructed
encoding.  The identifier and length octets are written on the same
line, with the contents octets following on subsequent lines.  If the
contents octets are a primitive encoding, the contents are written on
one line.  If the ASN.1 type of the contents is known from the
identifier octets, the contents octets are followed by a line showing
the value of the contents.  For example, the integer '3E9'H is shown
as 1001, and the character string '414243'H is shown as "ABC".

      To display an octet string as printable characters, the program
first checks whether the characters are printable in the IBM EBCDIC
code page.  If the characters are not printable...