6 x509 - Certificate display and signing utility
11 [B<-inform DER|PEM|NET>]
12 [B<-outform DER|PEM|NET>]
15 [B<-CAkeyform DER|PEM>]
37 [B<-signkey filename>]
43 [B<-CAserial filename>]
46 [B<-md2|-md5|-sha1|-mdc2>]
48 [B<-extfile filename>]
49 [B<-extensions section>]
53 The B<x509> command is a multi purpose certificate utility. It can be
54 used to display certificate information, convert certificates to
55 various forms, sign certificate requests like a "mini CA" or edit
56 certificate trust settings.
58 Since there are a large number of options they will split up into
62 =head1 INPUT, OUTPUT AND GENERAL PURPOSE OPTIONS
66 =item B<-inform DER|PEM|NET>
68 This specifies the input format normally the command will expect an X509
69 certificate but this can change if other options such as B<-req> are
70 present. The DER format is the DER encoding of the certificate and PEM
71 is the base64 encoding of the DER encoding with header and footer lines
72 added. The NET option is an obscure Netscape server format that is now
75 =item B<-outform DER|PEM|NET>
77 This specifies the output format, the options have the same meaning as the
82 This specifies the input filename to read a certificate from or standard input
83 if this option is not specified.
85 =item B<-out filename>
87 This specifies the output filename to write to or standard output by
90 =item B<-md2|-md5|-sha1|-mdc2>
92 the digest to use. This affects any signing or display option that uses a message
93 digest, such as the B<-fingerprint>, B<-signkey> and B<-CA> options. If not
94 specified then MD5 is used. If the key being used to sign with is a DSA key then
95 this option has no effect: SHA1 is always used with DSA keys.
100 =head1 DISPLAY OPTIONS
102 Note: the B<-alias> and B<-purpose> options are also display options
103 but are desribed in the B<TRUST OPTIONS> section.
109 prints out the certificate in text form. Full details are output including the
110 public key, signature algorithms, issuer and subject names, serial number
111 any extensions present and any trust settings.
115 this option prevents output of the encoded version of the request.
119 this option prints out the value of the modulus of the public key
120 contained in the certificate.
124 outputs the certificate serial number.
128 outputs the "hash" of the certificate subject name. This is used in OpenSSL to
129 form an index to allow certificates in a directory to be looked up by subject
134 outputs the subject name.
138 outputs the issuer name.
142 prints out the start date of the certificate, that is the notBefore date.
146 prints out the expiry date of the certificate, that is the notAfter date.
150 prints out the start and expiry dates of a certificate.
152 =item B<-fingerprint>
154 prints out the digest of the DER encoded version of the whole certificate.
158 this outputs the certificate in the form of a C source file.
162 =head1 TRUST SETTINGS
164 Please note these options are currently experimental and may well change.
166 A B<trusted certificate> is an ordinary certificate which has several
167 additional pieces of information attached to it such as the permitted
168 and prohibited uses of the certificate and an "alias".
170 Normally when a certificate is being verified at least one certificate
171 must be "trusted". By default a trusted certificate must be stored
172 locally and must be a root CA: any certificate chain ending in this CA
173 is then usable for any purpose.
175 Adding trust settings modifies this behaviour: if a certificate is being
176 verified and one of the certificate chain is marked as trusted for that
177 specific purpose then the verify succeeds without looking up any more
178 certificates. Similarly if the use is prohibited then the certificate
179 is automatically rejected. If a purpose is neither permitted nor prohibited
180 then the certificate extensions are checked for consistency with the required
181 purpose and the process continues.
183 If a root CA is reached then it must be marked as trusted for the required
184 purpose or the verify fails.
186 See the description of the B<verify> utility for more information on the
187 meaning of trust settings.
193 this causes B<x509> to output a B<trusted> certificate. An ordinary
194 or trusted certificate can be input but by default an ordinary
195 certificate is output and any trust settings are discarded. With the
196 B<-trustout> option a trusted certificate is output. A trusted
197 certificate is automatically output if any trust settings are modified.
199 =item B<-setalias arg>
201 sets the alias of the certificate. This will allow the certificate
202 to be reffered to using a nickname for example "Steve's Certificate".
206 outputs the certificate alias, if any.
210 clears all the permitted or trusted uses of the certificate.
214 clears all the prohibited or untrusted uses of the certificate.
216 =item B<-addtrust arg>
218 adds a trusted certificate use. Currently acceptable values
219 are all (any purpose), sslclient (SSL client use), sslserver
220 (SSL server use) email (S/MIME email) and objsign (Object signing).
222 =item B<-addreject arg>
224 adds a prohibited use. It accepts the same values as the B<-addtrust>
229 this option performs tests on the certificate extensions and outputs
230 the results. It checks to see if the certificate can be used as an
231 end user or CA certificate for various purposes. Since many commercial
232 certificates have invalid extensions it is possible that warnings will
233 be output for some certificates. Known problems have work arounds added.
237 =head1 SIGNING OPTIONS
239 The B<x509> utility can be used to sign certificates and requests: it
240 can thus behave like a "mini CA".
244 =item B<-signkey filename>
246 this option causes the input file to be self signed using the supplied
249 If the input file is a certificate it sets the issuer name to the
250 subject name (i.e. makes it self signed) changes the public key to the
251 supplied value and changes the start and end dates. The start date is
252 set to the current time and the end date is set to a value determined
253 by the B<-days> option. Any certificate extensions are retained unless
254 the B<-clrext> option is supplied.
256 If the input is a certificate request then a self signed certificate
257 is created using the supplied private key using the subject name in
262 delete any extensions from a certificate. This option is used when a
263 certificate is being created from another certificate (for example with
264 the B<-signkey> or the B<-CA> options). Normally all extensions are
267 =item B<-keyform PEM|DER>
269 specifies the format (DER or PEM) of the private key file used in the
274 specifies the number of days to make a certificate valid for. The default
279 converts a certificate into a certificate request. The B<-signkey> option
280 is used to pass the required private key.
284 by default a certificate is expected on input. With this option a
285 certificate request is expected instead.
287 =item B<-CA filename>
289 specifies the CA certificate to be used for signing. When this option is
290 present B<x509> behaves like a "mini CA". The input file is signed by this
291 CA using this option: that is its issuer name is set to the subject name
292 of the CA and it is digitally signed using the CAs private key.
294 This option is normally combined with the B<-req> option. Without the
295 B<-req> option the input is a certificate which must be self signed.
297 =item B<-CAkey filename>
299 sets the CA private key to sign a certificate with. If this option is
300 not specified then it is assumed that the CA private key is present in
301 the CA certificate file.
303 =item B<-CAserial filename>
305 sets the CA serial number file to use.
307 When the B<-CA> option is used to sign a certificate it uses a serial
308 number specified in a file. This file consist of one line containing
309 an even number of hex digits with the serial number to use. After each
310 use the serial number is incremented and written out to the file again.
312 The default filename consists of the CA certificate file base name with
313 ".srl" appended. For example if the CA certificate file is called
314 "mycacert.pem" it expects to find a serial number file called "mycacert.srl".
316 =item B<-CAcreateserial filename>
318 with this option the CA serial number file is created if it does not exist:
319 it will contain the serial number "01". Normally if the B<-CA> option is
320 specified and the serial number file does not exist it is an error.
322 =item B<-extfile filename>
324 file containing certificate extensions to use. If not specified then
325 no extensions are added to the certificate.
327 =item B<-extensions section>
329 the section to add certificate extensions from. If this option is not
330 specified then the extensions should either be contained in the unnamed
331 (default) section or the default section should contain a variable called
332 "extensions" which contains the section to use.
338 Note: in these examples the '\' means the example should be all on one
341 Display the contents of a certificate:
343 openssl x509 -in cert.pem -noout -text
345 Display the certificate serial number:
347 openssl x509 -in cert.pem -noout -serial
349 Display the certificate MD5 fingerprint:
351 openssl x509 -in cert.pem -noout -fingerprint
353 Display the certificate SHA1 fingerprint:
355 openssl x509 -sha1 -in cert.pem -noout -fingerprint
357 Convert a certificate from PEM to DER format:
359 openssl x509 -in cert.pem -inform PEM -out cert.der -outform DER
361 Convert a certificate to a certificate request:
363 openssl x509 -x509toreq -in cert.pem -out req.pem -signkey key.pem
365 Convert a certificate request into a self signed certificate using
368 openssl x509 -req -in careq.pem -config openssl.cnf -extensions v3_ca \
369 -signkey key.pem -out cacert.pem
371 Sign a certificate request using the CA certifcate above and add user
372 certificate extensions:
374 openssl x509 -req -in req.pem -config openssl.cnf -extensions v3_usr \
375 -CA cacert.pem -CAkey key.pem -CAcreateserial
378 Set a certificate to be trusted for SSL client use and change set its alias to
381 openssl x509 -in cert.pem -addtrust sslclient \
382 -alias "Steve's Class 1 CA" -out trust.pem
386 The PEM format uses the header and footer lines:
388 -----BEGIN CERTIFICATE----
389 -----END CERTIFICATE----
391 it will also handle files containing:
393 -----BEGIN X509 CERTIFICATE----
394 -----END X509 CERTIFICATE----
396 Trusted certificates have the lines
398 -----BEGIN TRUSTED CERTIFICATE----
399 -----END TRUSTED CERTIFICATE----
401 The B<-fingerprint> option takes the digest of the DER encoded certificate.
402 This is commonly called a "fingerprint". Because of the nature of message
403 digests the fingerprint of a certificate is unique to that certificate and
404 two certificates with the same fingerprint can be considered to be the same.
406 The Netscape fingerprint uses MD5 whereas MSIE uses SHA1.
410 The way DNs are printed is in a "historical SSLeay" format which doesn't
411 follow any published standard. It should follow some standard like RFC2253
412 or RFC1779 with options to make the stuff more readable.
414 Extensions in certificates are not transferred to certificate requests and
417 It is possible to produce invalid certificates or requests by specifying the
418 wrong private key or using inconsistent options in some cases: these should
421 There should be options to explicitly set such things as start and end
422 dates rather than an offset from the current time.
424 The code to implement the verify behaviour described in the B<TRUST SETTINGS>
425 is currently being developed. It thus describes the intended behavior rather
426 than the current behaviour. It is hoped that it will represent reality in
427 OpenSSL 0.9.5 and later.
431 req(1), ca(1), genrsa(1), gendsa(1)