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asn1parse(1ssl)


NAME

  asn1parse - ASN.1 parsing tool


SYNOPSIS

  openssl asn1parse [-inform PEM|DER] [-in filename] [-out filename] [-noout]
  [-offset number] [-length number] [-i] [-oid filename] [-strparse offset]


OPTIONS

  -inform DER|PEM
	  The input format.  DER is binary format and PEM (the default) is
	  base64 encoded.

  -in filename
	  The input file, default is standard input

  -out filename
	  Output file to place the DER encoded data into. If this option is
	  not present then no data will be output. This is most useful when
	  combined with the -strparse option.

  -noout  Does not output the parsed version of the input file.

  -offset number
	  Starting offset to begin parsing, default is start of file.

  -length number
	  Number of bytes to parse, default is until end of file.

  -i	  Indents the output according to the depth of the structures.

  -oidfilename
	  A file containing additional object identifiers (OIDs). The format
	  of this file is described in the Notes section below.

  -strparseoffset
	  Parses the content octets of the ASN.1 object starting at offset.
	  This option can be used multiple times to drill down into a nested
	  structure.


DESCRIPTION

  The asn1parse command is a diagnostic utility that can parse ASN.1
  structures. It can also be used to extract data from ASN.1 formatted data.


NOTES

  If an OID is not part of OpenSSL's internal table it will be represented in
  numerical form (for example 1.2.3.4). The file passed to the -oid option
  allows additional OIDs to be included. Each line consists of three columns,
  the first column is the OID in numerical format and should be followed by
  white space. The second column is the short name which is a single word
  followed by white space. The final column is the rest of the line and is
  the long name.  asn1parse displays the long name.  For example:

       1.2.3.4 shortName       A long name


RESTRICTIONS

  There should be options to change the format of input lines. The output of
  some ASN.1ssl types is not handled well.


EXAMPLES

  The output will typically contain lines like these:

	 0:d=0	hl=4 l= 681 cons: SEQUENCE

	 .....

	 229:d=3  hl=3 l= 141 prim: BIT STRING
	 373:d=2  hl=3 l= 162 cons: cont [ 3 ]
	 376:d=3  hl=3 l= 159 cons: SEQUENCE
	 379:d=4  hl=2 l=  29 cons: SEQUENCE
	 381:d=5  hl=2 l=   3 prim: OBJECT	      :X509v3 Subject Key Identifier
	 386:d=5  hl=2 l=  22 prim: OCTET STRING
	 410:d=4  hl=2 l= 112 cons: SEQUENCE
	 412:d=5  hl=2 l=   3 prim: OBJECT	      :X509v3 Authority Key Identifier
	 417:d=5  hl=2 l= 105 prim: OCTET STRING
	 524:d=4  hl=2 l=  12 cons: SEQUENCE

	 .....

  This example is part of a self-signed certificate. Each line starts with
  the offset in decimal. The d=XX specifies the current depth. The depth is
  increased within the scope of any SET or SEQUENCE. The hl=XX gives the
  header length (tag and length octets) of the current type. The l=XX gives
  the length of the contents octets.

  The -i option can be used to make the output more readable.

  Some knowledge of the ASN.1 structure is needed to interpret the output.

  In this example the bit string at offset 229 is the certificate public key.
  The content octets of this will contain the public key information. This
  can be examined by using the option -strparse 229 to yield:

       0:d=0  hl=3 l= 137 cons: SEQUENCE
       3:d=1  hl=3 l= 129 prim: INTEGER	  :E5D21E1F5C8D208EA7A2166C7FAF9F6BDF2059669C60876DDB70840
	       F1A5AAFA59699FE471F379F1DD6A487E7D5409AB6A88D4A9746E24B91
	       D8CF55DB3521015460C8EDE44EE8A4189F7A7BE77D6CD3A9AF2696F486855
	       CF58BF0EDF2B4068058C7A947F52548DDF7E15E96B385F86422BEA9064A3
	       EE9E1158A56E4A6F47E5897
       135:d=1	hl=2 l=	  3 prim: INTEGER	 :010001

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