1=pod 2{- OpenSSL::safe::output_do_not_edit_headers(); -} 3 4=head1 NAME 5 6openssl-asn1parse - ASN.1 parsing command 7 8=head1 SYNOPSIS 9 10B<openssl> B<asn1parse> 11[B<-help>] 12[B<-inform> B<DER>|B<PEM>|B<B64>] 13[B<-in> I<filename>] 14[B<-out> I<filename>] 15[B<-noout>] 16[B<-offset> I<number>] 17[B<-length> I<number>] 18[B<-i>] 19[B<-oid> I<filename>] 20[B<-dump>] 21[B<-dlimit> I<num>] 22[B<-strparse> I<offset>] 23[B<-genstr> I<string>] 24[B<-genconf> I<file>] 25[B<-strictpem>] 26[B<-item> I<name>] 27 28=head1 DESCRIPTION 29 30This command is a diagnostic utility that can parse ASN.1 structures. 31It can also be used to extract data from ASN.1 formatted data. 32 33=head1 OPTIONS 34 35=over 4 36 37=item B<-help> 38 39Print out a usage message. 40 41=item B<-inform> B<DER>|B<PEM>|B<B64> 42 43The input format; the default is B<PEM>. 44See L<openssl-format-options(1)> for details. 45 46=item B<-in> I<filename> 47 48The input file, default is standard input. 49 50=item B<-out> I<filename> 51 52Output file to place the DER encoded data into. If this 53option is not present then no data will be output. This is most useful when 54combined with the B<-strparse> option. 55 56=item B<-noout> 57 58Don't output the parsed version of the input file. 59 60=item B<-offset> I<number> 61 62Starting offset to begin parsing, default is start of file. 63 64=item B<-length> I<number> 65 66Number of bytes to parse, default is until end of file. 67 68=item B<-i> 69 70Indents the output according to the "depth" of the structures. 71 72=item B<-oid> I<filename> 73 74A file containing additional OBJECT IDENTIFIERs (OIDs). The format of this 75file is described in the NOTES section below. 76 77=item B<-dump> 78 79Dump unknown data in hex format. 80 81=item B<-dlimit> I<num> 82 83Like B<-dump>, but only the first B<num> bytes are output. 84 85=item B<-strparse> I<offset> 86 87Parse the contents octets of the ASN.1 object starting at B<offset>. This 88option can be used multiple times to "drill down" into a nested structure. 89 90=item B<-genstr> I<string>, B<-genconf> I<file> 91 92Generate encoded data based on I<string>, I<file> or both using 93L<ASN1_generate_nconf(3)> format. If I<file> only is 94present then the string is obtained from the default section using the name 95B<asn1>. The encoded data is passed through the ASN1 parser and printed out as 96though it came from a file, the contents can thus be examined and written to a 97file using the B<-out> option. 98 99=item B<-strictpem> 100 101If this option is used then B<-inform> will be ignored. Without this option any 102data in a PEM format input file will be treated as being base64 encoded and 103processed whether it has the normal PEM BEGIN and END markers or not. This 104option will ignore any data prior to the start of the BEGIN marker, or after an 105END marker in a PEM file. 106 107=item B<-item> I<name> 108 109Attempt to decode and print the data as an B<ASN1_ITEM> I<name>. This can be 110used to print out the fields of any supported ASN.1 structure if the type is 111known. 112 113=back 114 115=head2 Output 116 117The output will typically contain lines like this: 118 119 0:d=0 hl=4 l= 681 cons: SEQUENCE 120 121..... 122 123 229:d=3 hl=3 l= 141 prim: BIT STRING 124 373:d=2 hl=3 l= 162 cons: cont [ 3 ] 125 376:d=3 hl=3 l= 159 cons: SEQUENCE 126 379:d=4 hl=2 l= 29 cons: SEQUENCE 127 381:d=5 hl=2 l= 3 prim: OBJECT :X509v3 Subject Key Identifier 128 386:d=5 hl=2 l= 22 prim: OCTET STRING 129 410:d=4 hl=2 l= 112 cons: SEQUENCE 130 412:d=5 hl=2 l= 3 prim: OBJECT :X509v3 Authority Key Identifier 131 417:d=5 hl=2 l= 105 prim: OCTET STRING 132 524:d=4 hl=2 l= 12 cons: SEQUENCE 133 134..... 135 136This example is part of a self-signed certificate. Each line starts with the 137offset in decimal. C<d=XX> specifies the current depth. The depth is increased 138within the scope of any SET or SEQUENCE. C<hl=XX> gives the header length 139(tag and length octets) of the current type. C<l=XX> gives the length of 140the contents octets. 141 142The B<-i> option can be used to make the output more readable. 143 144Some knowledge of the ASN.1 structure is needed to interpret the output. 145 146In this example the BIT STRING at offset 229 is the certificate public key. 147The contents octets of this will contain the public key information. This can 148be examined using the option C<-strparse 229> to yield: 149 150 0:d=0 hl=3 l= 137 cons: SEQUENCE 151 3:d=1 hl=3 l= 129 prim: INTEGER :E5D21E1F5C8D208EA7A2166C7FAF9F6BDF2059669C60876DDB70840F1A5AAFA59699FE471F379F1DD6A487E7D5409AB6A88D4A9746E24B91D8CF55DB3521015460C8EDE44EE8A4189F7A7BE77D6CD3A9AF2696F486855CF58BF0EDF2B4068058C7A947F52548DDF7E15E96B385F86422BEA9064A3EE9E1158A56E4A6F47E5897 152 135:d=1 hl=2 l= 3 prim: INTEGER :010001 153 154=head1 NOTES 155 156If an OID is not part of OpenSSL's internal table it will be represented in 157numerical form (for example 1.2.3.4). The file passed to the B<-oid> option 158allows additional OIDs to be included. Each line consists of three columns, 159the first column is the OID in numerical format and should be followed by white 160space. The second column is the "short name" which is a single word followed 161by whitespace. The final column is the rest of the line and is the 162"long name". Example: 163 164C<1.2.3.4 shortName A long name> 165 166For any OID with an associated short and long name, this command will display 167the long name. 168 169=head1 EXAMPLES 170 171Parse a file: 172 173 openssl asn1parse -in file.pem 174 175Parse a DER file: 176 177 openssl asn1parse -inform DER -in file.der 178 179Generate a simple UTF8String: 180 181 openssl asn1parse -genstr 'UTF8:Hello World' 182 183Generate and write out a UTF8String, don't print parsed output: 184 185 openssl asn1parse -genstr 'UTF8:Hello World' -noout -out utf8.der 186 187Generate using a config file: 188 189 openssl asn1parse -genconf asn1.cnf -noout -out asn1.der 190 191Example config file: 192 193 asn1=SEQUENCE:seq_sect 194 195 [seq_sect] 196 197 field1=BOOL:TRUE 198 field2=EXP:0, UTF8:some random string 199 200 201=head1 BUGS 202 203There should be options to change the format of output lines. The output of some 204ASN.1 types is not well handled (if at all). 205 206=head1 SEE ALSO 207 208L<openssl(1)>, 209L<ASN1_generate_nconf(3)> 210 211=head1 COPYRIGHT 212 213Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved. 214 215Licensed under the Apache License 2.0 (the "License"). You may not use 216this file except in compliance with the License. You can obtain a copy 217in the file LICENSE in the source distribution or at 218L<https://www.openssl.org/source/license.html>. 219 220=cut 221
