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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
       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 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
              "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 -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
       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                                                     UNBER(1)