asn(n) 0.1 asn "ASN.1"
asn - ASN.1 BER encoder/decoder
TABLE OF CONTENTS
SYNOPSIS
DESCRIPTION
PUBLIC API
ENCODER
DECODER
EXAMPLES
KEYWORDS
COPYRIGHT
package require Tcl 8.2
package require asn ?0.1?
The asn package provides partial de- and encoder
commands for BER encoded ASN.1 data.
ASN.1 is a standard Abstract Syntax Notation, and BER are its
Basic Encoding Rules.
See http://asn1.elibel.tm.fr/en/standards/index.htm for more
information about the standard.
Also see http://luca.ntop.org/Teaching/Appunti/asn1.html for
A Layman's Guide to a Subset of ASN.1, BER, and DER, an RSA
Laboratories Technical Note by Burton S. Kaliski Jr. (Revised November
1, 1993). A text version of this note is part of the module sources
and should be read by any implementor.
- ::asn::asnSequence evalue...
-
Takes zero or more encoded values, packs them into an ASN sequence and
returns its encoded binary form.
NOTE: Shouldn't that be one or more ?! However the
command does no checking of this.
- ::asn::asnSet evalue...
-
Takes zero or more encoded values, packs them into an ASN set and
returns its encoded binary form.
NOTE: Shouldn't that be one or more ?! However the
command does no checking of this.
- ::asn::asnApplicationConstr appNumber evalue...
-
Takes zero or more encoded values, packs them into an ASN application
construct and returns its encoded binary form.
NOTE: Shouldn't that be one or more ?! However the
command does no checking of this.
- ::asn::asnApplication appNumber data
-
Takes a single encoded value data, packs it into an ASN
application construct and returns its encoded binary form.
- ::asn::asnChoice appNumber evalue...
-
Takes zero or more encoded values, packs them into an ASN choice
construct and returns its encoded binary form.
NOTE: Shouldn't that be one or more ?! However the
command does no checking of this.
- ::asn::asnChoiceConstr appNumber evalue...
-
Takes zero or more encoded values, packs them into an ASN choice
construct and returns its encoded binary form.
NOTE: Shouldn't that be one or more ?! However the
command does no checking of this.
The only difference between this and the ::asn::asnChoice coming
before seems to lie in the tag value.
- ::asn::asnInteger number
-
Returns the encoded form of the specified integer
number.
- ::asn::asnEnumeration number
-
Returns the encoded form of the specified enumeration id
number.
- ::asn::asnBoolean bool
-
Returns the encoded form of the specified boolean value
bool.
- ::asn::asnOctetString string
-
Returns the encoded form of the specified string.
General notes:
-
All decoder commands take two arguments. These arguments are variable
names, except for ::asn::asnGetResponse. The first variable
contains the encoded ASN value to decode at the beginning, and more,
and the second variable is where the value is stored to. The remainder
of the input after the decoded value is stored back into the
datavariable.
-
After extraction the data variable is always modified first, before by
writing the extracted value to its variable. This means that if both
arguments refer to the same variable, it will always contain the
extracted value after the call, and not the remainder of the input.
- ::asn::asnGetResponse chan data_var
-
Reads an encoded ASN sequence from the channel chan and
stores it into the variable named by data_var.
- ::asn::asnGetInteger data_var int_var
-
Assumes that an encoded integer value is at the front of the data
stored in the variable named data_var, extracts and stores it
into the variable named by int_var. Additionally removes all
bytes associated with the value from the data for further processing
by the following decoder commands.
- ::asn::asnGetEnumeration data_var enum_var
-
Assumes that an enumeration id is at the front of the data stored in
the variable named data_var, and stores it into the variable
named by enum_var. Additionally removes all bytes associated
with the value from the data for further processing by the following
decoder commands.
- ::asn::asnGetOctetString data_var string_var
-
Assumes that a string is at the front of the data stored in the
variable named data_var, and stores it into the variable named
by string_var. Additionally removes all bytes associated with
the value from the data for further processing by the following
decoder commands.
- ::asn::asnGetSequence data_var sequence_var
-
Assumes that an ASN sequence is at the front of the data stored in the
variable named data_var, and stores it into the variable named
by sequence_var. Additionally removes all bytes associated with
the value from the data for further processing by the following
decoder commands.
The data in sequence_var is encoded binary and has to be
further decoded according to the definition of the sequence, using the
decoder commands here.
- ::asn::asnGetSet data_var set_var
-
Assumes that an ASN set is at the front of the data stored in the
variable named data_var, and stores it into the variable named
by set_var. Additionally removes all bytes associated with the
value from the data for further processing by the following decoder
commands.
The data in set_var is encoded binary and has to be further
decoded according to the definition of the set, using the decoder
commands here.
- ::asn::asnGetApplication data_var appNumber_var
-
Assumes that an ASN application construct is at the front of the data
stored in the variable named data_var, and stores its id into
the variable named by appNumber_var. Additionally removes all
bytes associated with the value from the data for further processing
by the following decoder commands.
It is the responsibility of the caller to decode the remainder of the
application construct based on the id retrieved by this command, using
the decoder commands here.
Examples for the usage of this package can be found in the
implementation of package ldap.
asn, ber, cer, der, internet, protocol, x.208, x.209
Copyright © 2004 Andreas Kupries <andreas_kupries@users.sourceforge.net>
Copyright © 2004 Jochen Loewer <loewerj@web.de>