1 =pod 2 {- OpenSSL::safe::output_do_not_edit_headers(); -} 3 4 =head1 NAME 5 6 openssl-asn1parse - ASN.1 parsing command 7 8 =head1 SYNOPSIS 9 10 B<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 30 This command is a diagnostic utility that can parse ASN.1 structures. 31 It 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 39 Print out a usage message. 40 41 =item B<-inform> B<DER>|B<PEM>|B<B64> 42 43 The input format; the default is B<PEM>. 44 See L<openssl-format-options(1)> for details. 45 46 =item B<-in> I<filename> 47 48 The input file, default is standard input. 49 50 =item B<-out> I<filename> 51 52 Output file to place the DER encoded data into. If this 53 option is not present then no data will be output. This is most useful when 54 combined with the B<-strparse> option. 55 56 =item B<-noout> 57 58 Don't output the parsed version of the input file. 59 60 =item B<-offset> I<number> 61 62 Starting offset to begin parsing, default is start of file. 63 64 =item B<-length> I<number> 65 66 Number of bytes to parse, default is until end of file. 67 68 =item B<-i> 69 70 Indents the output according to the "depth" of the structures. 71 72 =item B<-oid> I<filename> 73 74 A file containing additional OBJECT IDENTIFIERs (OIDs). The format of this 75 file is described in the NOTES section below. 76 77 =item B<-dump> 78 79 Dump unknown data in hex format. 80 81 =item B<-dlimit> I<num> 82 83 Like B<-dump>, but only the first B<num> bytes are output. 84 85 =item B<-strparse> I<offset> 86 87 Parse the contents octets of the ASN.1 object starting at B<offset>. This 88 option can be used multiple times to "drill down" into a nested structure. 89 90 =item B<-genstr> I<string>, B<-genconf> I<file> 91 92 Generate encoded data based on I<string>, I<file> or both using 93 L<ASN1_generate_nconf(3)> format. If I<file> only is 94 present then the string is obtained from the default section using the name 95 B<asn1>. The encoded data is passed through the ASN1 parser and printed out as 96 though it came from a file, the contents can thus be examined and written to a 97 file using the B<-out> option. 98 99 =item B<-strictpem> 100 101 If this option is used then B<-inform> will be ignored. Without this option any 102 data in a PEM format input file will be treated as being base64 encoded and 103 processed whether it has the normal PEM BEGIN and END markers or not. This 104 option will ignore any data prior to the start of the BEGIN marker, or after an 105 END marker in a PEM file. 106 107 =item B<-item> I<name> 108 109 Attempt to decode and print the data as an B<ASN1_ITEM> I<name>. This can be 110 used to print out the fields of any supported ASN.1 structure if the type is 111 known. 112 113 =back 114 115 =head2 Output 116 117 The 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 ..... 135 136 This example is part of a self-signed certificate. Each line starts with the 137 offset in decimal. C<d=XX> specifies the current depth. The depth is increased 138 within 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 140 the contents octets. 141 142 The B<-i> option can be used to make the output more readable. 143 144 Some knowledge of the ASN.1 structure is needed to interpret the output. 145 146 In this example the BIT STRING at offset 229 is the certificate public key. 147 The contents octets of this will contain the public key information. This can 148 be 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 155 156 If an OID is not part of OpenSSL's internal table it will be represented in 157 numerical form (for example 1.2.3.4). The file passed to the B<-oid> option 158 allows additional OIDs to be included. Each line consists of three columns, 159 the first column is the OID in numerical format and should be followed by white 160 space. The second column is the "short name" which is a single word followed 161 by whitespace. The final column is the rest of the line and is the 162 "long name". Example: 163 164 C<1.2.3.4 shortName A long name> 165 166 For any OID with an associated short and long name, this command will display 167 the long name. 168 169 =head1 EXAMPLES 170 171 Parse a file: 172 173 openssl asn1parse -in file.pem 174 175 Parse a DER file: 176 177 openssl asn1parse -inform DER -in file.der 178 179 Generate a simple UTF8String: 180 181 openssl asn1parse -genstr 'UTF8:Hello World' 182 183 Generate and write out a UTF8String, don't print parsed output: 184 185 openssl asn1parse -genstr 'UTF8:Hello World' -noout -out utf8.der 186 187 Generate using a config file: 188 189 openssl asn1parse -genconf asn1.cnf -noout -out asn1.der 190 191 Example 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 202 203 There should be options to change the format of output lines. The output of some 204 ASN.1 types is not well handled (if at all). 205 206 =head1 SEE ALSO 207 208 L<openssl(1)>, 209 L<ASN1_generate_nconf(3)> 210 211 =head1 COPYRIGHT 212 213 Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved. 214 215 Licensed under the Apache License 2.0 (the "License"). You may not use 216 this file except in compliance with the License. You can obtain a copy 217 in the file LICENSE in the source distribution or at 218 L<https://www.openssl.org/source/license.html>. 219 220 =cut 221
Indexes created Sat Feb 28 05:31:39 UTC 2026