UNBER(1)		       ASN.1 BER Decoder		      UNBER(1)

NAME

       unber - ASN.1 BER Decoder

SYNOPSIS

       unber [-1] [-iindent] [-m] [-p] [-sskip] [-thex-string] [-] [infile...]

DESCRIPTION

       unber presents the internal structure of  BER-encoded  files  as  human
       readable text.  A single dash denotes the standard input.

       (The  DER  and  CER  formats  are  subsets of the BER and are also sup-
       ported.)

OPTIONS

       -1     Do not attempt to read the next BER structure  after  the  first
	      one.   This may be useful if the input contains garbage past the
	      single BER sequence.  By default, unber continues decoding until
	      the end of file (input stream).

       -i indent
	      Use  the	specified  number  of  spaces  for output indentation.
	      Default is 4 spaces.

       -m     Generate shorter output  while  still  preserving  BER  encoding
	      information.

       -p     Do  not  attempt	pretty-printing of known ASN.1 types (BOOLEAN,
	      INTEGER, OBJECT IDENTIFIER, etc). By default, some  ASN.1  types
	      are  converted  into  the  text  representation.	This option is
	      required for enber(1).

       -s skip
	      Ignore the first skip bytes in  the  input  stream;  useful  for
	      stripping off lower level protocol framing data.

       -t hex-string
	      Interpret  the  hex-string  as  a sequence of hexadecimal values
	      representing the start of BER  TLV  encoding.  Print  the  human
	      readable explanation.

XML FORMAT

       unber  dumps  the output in the regular XML format which preserves most
       of the information from the underlying binary encoding.

       The XML opening tag format is as follows:

       <tform O="off" T="tag" TL="tl_len" V="{Indefinite|v_len}" [A="type"] [F]>

       Where:

       tform  Encoding form the value is in: primitive	("P")  or  constructed
	      ("C") or constructed with indefinite length ("I")

       off    Offset of the encoded element in the unber input stream.

       tag    The tag class and value in human readable form.

       tl_len The length of the TL (BER Tag and Length) encoding.

       v_len  The  length  of the value (V, encoded by the L), may be "Indefi-
	      nite".

       type   Likely name of the underlying ASN.1 type (for UNIVERSAL tags).

       [F]    Indicates that the value was reformatted (pretty-printed).  This
	      will  never  appear in the output produced using -p command line
	      option.

       Sample XML output:

       <I O="0" T="[UNIVERSAL 16]" TL="2" V="Indefinite" A="SEQUENCE">
	 <P O="2" T="[UNIVERSAL 19]" TL="2" V="2" A="PrintableString">US</P>
	 <C O="6" T="[UNIVERSAL 16]" TL="2" V="6" A="SEQUENCE">
	   <P O="8" T="[UNIVERSAL 2]" TL="2" V="4" A="INTEGER" F>832970823</P>
	 </C O="14" T="[UNIVERSAL 16]" A="SEQUENCE" L="8">
       </I O="14" T="[UNIVERSAL 0]" TL="2" L="16">

EXAMPLES

       Decode the given Tag/Length sequence specified in hexadecimal form:

	   unber  -t "bf 20"

       Decode the DER file using two-spaces indentation:

	   unber  -i 2	 filename.der

       Decode the binary stream taken from the standard input:

	   cat ... | unber -

       Decode the binary stream and encode it back into  an  identical	stream
       (see enber(1)):

	   cat ... | unber -p - | enber - > filename.ber

FOOTNOTES

       The constructed XML output is not necessarily well-formed.

       When  indefinite length encoding is being used, the BER sequence, which
       is not terminated with the end-of-content octets, will cause the termi-
       nating  </I>  XML tag to disappear.  Thus, invalid BER framing directly
       causes invalid XML output.

       The enber(1) utility understands such XML correctly.

SEE ALSO

       enber(1), asn1c(1)

AUTHORS

       Lev Walkin <vlm@lionet.info>



ASN.1 BER Decoder						      UNBER(1)