NAME

       unber -- the ASN.1 BER Decoder

SYNOPSIS

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

DESCRIPTION

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

       (The DER and CER formats are subsets of the BER and are also supported.)

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 to pretty-print 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 if the unber(1) output is used as an input to 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="t_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.

       t_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 "Indefinite".

       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 the -p command line option.

   Example 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 filename.der | unber -

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

              cat filename.der | 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 terminating </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                                  2016-01-23                                           unber(1)