]>
Commit | Line | Data |
---|---|---|
e3775a33 DSH |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | smime - S/MIME utility | |
6 | ||
7 | =head1 SYNOPSIS | |
8 | ||
9 | B<openssl> B<smime> | |
169394d4 | 10 | [B<-help>] |
e3775a33 DSH |
11 | [B<-encrypt>] |
12 | [B<-decrypt>] | |
13 | [B<-sign>] | |
d884c5ba | 14 | [B<-resign>] |
e3775a33 DSH |
15 | [B<-verify>] |
16 | [B<-pk7out>] | |
2197494d DSH |
17 | [B<-binary>] |
18 | [B<-crlfeol>] | |
e5fa864f | 19 | [B<-[cipher]>] |
e3775a33 | 20 | [B<-in file>] |
ce21d108 HK |
21 | [B<-CAfile file>] |
22 | [B<-CApath dir>] | |
40e2d76b MC |
23 | [B<-no-CAfile>] |
24 | [B<-no-CApath>] | |
e42d84be HK |
25 | [B<-attime timestamp>] |
26 | [B<-check_ss_sig>] | |
27 | [B<-crl_check>] | |
28 | [B<-crl_check_all>] | |
29 | [B<-explicit_policy>] | |
30 | [B<-extended_crl>] | |
31 | [B<-ignore_critical>] | |
32 | [B<-inhibit_any>] | |
33 | [B<-inhibit_map>] | |
e42d84be HK |
34 | [B<-partial_chain>] |
35 | [B<-policy arg>] | |
36 | [B<-policy_check>] | |
37 | [B<-policy_print>] | |
38 | [B<-purpose purpose>] | |
39 | [B<-suiteB_128>] | |
40 | [B<-suiteB_128_only>] | |
41 | [B<-suiteB_192>] | |
6d3d5793 | 42 | [B<-trusted_first>] |
fa7b0111 | 43 | [B<-no_alt_chains>] |
e42d84be | 44 | [B<-use_deltas>] |
fbb82a60 | 45 | [B<-auth_level num>] |
e42d84be HK |
46 | [B<-verify_depth num>] |
47 | [B<-verify_email email>] | |
48 | [B<-verify_hostname hostname>] | |
49 | [B<-verify_ip ip>] | |
50 | [B<-verify_name name>] | |
51 | [B<-x509_strict>] | |
e3775a33 DSH |
52 | [B<-certfile file>] |
53 | [B<-signer file>] | |
54 | [B<-recip file>] | |
fd13f0ee | 55 | [B<-inform SMIME|PEM|DER>] |
84b65340 | 56 | [B<-passin arg>] |
e3775a33 DSH |
57 | [B<-inkey file>] |
58 | [B<-out file>] | |
fd13f0ee DSH |
59 | [B<-outform SMIME|PEM|DER>] |
60 | [B<-content file>] | |
e3775a33 DSH |
61 | [B<-to addr>] |
62 | [B<-from ad>] | |
63 | [B<-subject s>] | |
64 | [B<-text>] | |
76b46e77 DSH |
65 | [B<-indef>] |
66 | [B<-noindef>] | |
67 | [B<-stream>] | |
d13e4eb0 | 68 | [B<-rand file(s)>] |
d884c5ba | 69 | [B<-md digest>] |
e3775a33 DSH |
70 | [cert.pem]... |
71 | ||
72 | =head1 DESCRIPTION | |
73 | ||
74 | The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and | |
75 | verify S/MIME messages. | |
76 | ||
3dfda1a6 | 77 | =head1 OPTIONS |
e3775a33 | 78 | |
76b46e77 | 79 | There are six operation options that set the type of operation to be performed. |
e3775a33 DSH |
80 | The meaning of the other options varies according to the operation type. |
81 | ||
82 | =over 4 | |
83 | ||
169394d4 MR |
84 | =item B<-help> |
85 | ||
86 | Print out a usage message. | |
87 | ||
e3775a33 DSH |
88 | =item B<-encrypt> |
89 | ||
90 | encrypt mail for the given recipient certificates. Input file is the message | |
91 | to be encrypted. The output file is the encrypted mail in MIME format. | |
92 | ||
2a9afa40 RS |
93 | Note that no revocation check is done for the recipient cert, so if that |
94 | key has been compromised, others may be able to decrypt the text. | |
95 | ||
e3775a33 DSH |
96 | =item B<-decrypt> |
97 | ||
98 | decrypt mail using the supplied certificate and private key. Expects an | |
99 | encrypted mail message in MIME format for the input file. The decrypted mail | |
100 | is written to the output file. | |
101 | ||
102 | =item B<-sign> | |
103 | ||
104 | sign mail using the supplied certificate and private key. Input file is | |
105 | the message to be signed. The signed message in MIME format is written | |
106 | to the output file. | |
107 | ||
108 | =item B<-verify> | |
109 | ||
110 | verify signed mail. Expects a signed mail message on input and outputs | |
111 | the signed data. Both clear text and opaque signing is supported. | |
112 | ||
113 | =item B<-pk7out> | |
114 | ||
115 | takes an input message and writes out a PEM encoded PKCS#7 structure. | |
116 | ||
d884c5ba DSH |
117 | =item B<-resign> |
118 | ||
119 | resign a message: take an existing message and one or more new signers. | |
120 | ||
e3775a33 DSH |
121 | =item B<-in filename> |
122 | ||
123 | the input message to be encrypted or signed or the MIME message to | |
124 | be decrypted or verified. | |
125 | ||
fd13f0ee DSH |
126 | =item B<-inform SMIME|PEM|DER> |
127 | ||
128 | this specifies the input format for the PKCS#7 structure. The default | |
129 | is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER> | |
130 | format change this to expect PEM and DER format PKCS#7 structures | |
131 | instead. This currently only affects the input format of the PKCS#7 | |
132 | structure, if no PKCS#7 structure is being input (for example with | |
133 | B<-encrypt> or B<-sign>) this option has no effect. | |
134 | ||
e3775a33 DSH |
135 | =item B<-out filename> |
136 | ||
137 | the message text that has been decrypted or verified or the output MIME | |
138 | format message that has been signed or verified. | |
139 | ||
fd13f0ee DSH |
140 | =item B<-outform SMIME|PEM|DER> |
141 | ||
142 | this specifies the output format for the PKCS#7 structure. The default | |
143 | is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER> | |
144 | format change this to write PEM and DER format PKCS#7 structures | |
145 | instead. This currently only affects the output format of the PKCS#7 | |
146 | structure, if no PKCS#7 structure is being output (for example with | |
147 | B<-verify> or B<-decrypt>) this option has no effect. | |
148 | ||
76b46e77 DSH |
149 | =item B<-stream -indef -noindef> |
150 | ||
151 | the B<-stream> and B<-indef> options are equivalent and enable streaming I/O | |
152 | for encoding operations. This permits single pass processing of data without | |
153 | the need to hold the entire contents in memory, potentially supporting very | |
154 | large files. Streaming is automatically set for S/MIME signing with detached | |
155 | data if the output format is B<SMIME> it is currently off by default for all | |
156 | other operations. | |
157 | ||
158 | =item B<-noindef> | |
159 | ||
160 | disable streaming I/O where it would produce and indefinite length constructed | |
161 | encoding. This option currently has no effect. In future streaming will be | |
162 | enabled by default on all relevant operations and this option will disable it. | |
163 | ||
fd13f0ee DSH |
164 | =item B<-content filename> |
165 | ||
166 | This specifies a file containing the detached content, this is only | |
167 | useful with the B<-verify> command. This is only usable if the PKCS#7 | |
168 | structure is using the detached signature form where the content is | |
169 | not included. This option will override any content if the input format | |
170 | is S/MIME and it uses the multipart/signed MIME content type. | |
171 | ||
e3775a33 DSH |
172 | =item B<-text> |
173 | ||
174 | this option adds plain text (text/plain) MIME headers to the supplied | |
175 | message if encrypting or signing. If decrypting or verifying it strips | |
1bc74519 | 176 | off text headers: if the decrypted or verified message is not of MIME |
e3775a33 DSH |
177 | type text/plain then an error occurs. |
178 | ||
179 | =item B<-CAfile file> | |
180 | ||
181 | a file containing trusted CA certificates, only used with B<-verify>. | |
182 | ||
183 | =item B<-CApath dir> | |
184 | ||
185 | a directory containing trusted CA certificates, only used with | |
186 | B<-verify>. This directory must be a standard certificate directory: that | |
187 | is a hash of each subject name (using B<x509 -hash>) should be linked | |
188 | to each certificate. | |
189 | ||
40e2d76b MC |
190 | =item B<-no-CAfile> |
191 | ||
192 | Do not load the trusted CA certificates from the default file location | |
193 | ||
194 | =item B<-no-CApath> | |
195 | ||
196 | Do not load the trusted CA certificates from the default directory location | |
197 | ||
d884c5ba DSH |
198 | =item B<-md digest> |
199 | ||
200 | digest algorithm to use when signing or resigning. If not present then the | |
201 | default digest algorithm for the signing key will be used (usually SHA1). | |
202 | ||
e5fa864f | 203 | =item B<-[cipher]> |
e3775a33 | 204 | |
e5fa864f DSH |
205 | the encryption algorithm to use. For example DES (56 bits) - B<-des>, |
206 | triple DES (168 bits) - B<-des3>, | |
1bc74519 | 207 | EVP_get_cipherbyname() function) can also be used preceded by a dash, for |
9446daac | 208 | example B<-aes-128-cbc>. See L<B<enc>|enc(1)> for list of ciphers |
e5fa864f | 209 | supported by your version of OpenSSL. |
d884c5ba | 210 | |
6f719f06 | 211 | If not specified triple DES is used. Only used with B<-encrypt>. |
e3775a33 DSH |
212 | |
213 | =item B<-nointern> | |
214 | ||
215 | when verifying a message normally certificates (if any) included in | |
216 | the message are searched for the signing certificate. With this option | |
217 | only the certificates specified in the B<-certfile> option are used. | |
218 | The supplied certificates can still be used as untrusted CAs however. | |
219 | ||
220 | =item B<-noverify> | |
221 | ||
222 | do not verify the signers certificate of a signed message. | |
223 | ||
224 | =item B<-nochain> | |
225 | ||
19d2bb57 | 226 | do not do chain verification of signers certificates: that is don't |
e3775a33 DSH |
227 | use the certificates in the signed message as untrusted CAs. |
228 | ||
229 | =item B<-nosigs> | |
230 | ||
231 | don't try to verify the signatures on the message. | |
232 | ||
233 | =item B<-nocerts> | |
234 | ||
235 | when signing a message the signer's certificate is normally included | |
236 | with this option it is excluded. This will reduce the size of the | |
237 | signed message but the verifier must have a copy of the signers certificate | |
238 | available locally (passed using the B<-certfile> option for example). | |
239 | ||
240 | =item B<-noattr> | |
241 | ||
242 | normally when a message is signed a set of attributes are included which | |
243 | include the signing time and supported symmetric algorithms. With this | |
244 | option they are not included. | |
245 | ||
246 | =item B<-binary> | |
247 | ||
248 | normally the input message is converted to "canonical" format which is | |
3fc9635e DSH |
249 | effectively using CR and LF as end of line: as required by the S/MIME |
250 | specification. When this option is present no translation occurs. This | |
251 | is useful when handling binary data which may not be in MIME format. | |
e3775a33 | 252 | |
2197494d DSH |
253 | =item B<-crlfeol> |
254 | ||
255 | normally the output file uses a single B<LF> as end of line. When this | |
256 | option is present B<CRLF> is used instead. | |
257 | ||
e3775a33 DSH |
258 | =item B<-nodetach> |
259 | ||
260 | when signing a message use opaque signing: this form is more resistant | |
261 | to translation by mail relays but it cannot be read by mail agents that | |
262 | do not support S/MIME. Without this option cleartext signing with | |
263 | the MIME type multipart/signed is used. | |
264 | ||
265 | =item B<-certfile file> | |
266 | ||
267 | allows additional certificates to be specified. When signing these will | |
268 | be included with the message. When verifying these will be searched for | |
269 | the signers certificates. The certificates should be in PEM format. | |
270 | ||
271 | =item B<-signer file> | |
272 | ||
d884c5ba DSH |
273 | a signing certificate when signing or resigning a message, this option can be |
274 | used multiple times if more than one signer is required. If a message is being | |
275 | verified then the signers certificates will be written to this file if the | |
276 | verification was successful. | |
e3775a33 DSH |
277 | |
278 | =item B<-recip file> | |
279 | ||
280 | the recipients certificate when decrypting a message. This certificate | |
281 | must match one of the recipients of the message or an error occurs. | |
282 | ||
283 | =item B<-inkey file> | |
284 | ||
285 | the private key to use when signing or decrypting. This must match the | |
286 | corresponding certificate. If this option is not specified then the | |
287 | private key must be included in the certificate file specified with | |
d884c5ba DSH |
288 | the B<-recip> or B<-signer> file. When signing this option can be used |
289 | multiple times to specify successive keys. | |
e3775a33 | 290 | |
84b65340 DSH |
291 | =item B<-passin arg> |
292 | ||
293 | the private key password source. For more information about the format of B<arg> | |
9b86974e | 294 | see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>. |
84b65340 | 295 | |
d13e4eb0 DSH |
296 | =item B<-rand file(s)> |
297 | ||
298 | a file or files containing random data used to seed the random number | |
9b86974e | 299 | generator, or an EGD socket (see L<RAND_egd(3)>). |
35ed393e | 300 | Multiple files can be specified separated by an OS-dependent character. |
b87ef946 | 301 | The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for |
a4cfd178 | 302 | all others. |
d13e4eb0 | 303 | |
e3775a33 DSH |
304 | =item B<cert.pem...> |
305 | ||
306 | one or more certificates of message recipients: used when encrypting | |
1bc74519 | 307 | a message. |
e3775a33 DSH |
308 | |
309 | =item B<-to, -from, -subject> | |
310 | ||
311 | the relevant mail headers. These are included outside the signed | |
312 | portion of a message so they may be included manually. If signing | |
313 | then many S/MIME mail clients check the signers certificate's email | |
314 | address matches that specified in the From: address. | |
315 | ||
e42d84be | 316 | =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>, |
d33def66 VD |
317 | B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>, |
318 | B<-inhibit_map>, B<-no_alt_chains>, B<-partial_chain>, B<-policy>, | |
e42d84be | 319 | B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>, |
d33def66 | 320 | B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>, |
fbb82a60 VD |
321 | B<-auth_level>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>, |
322 | B<-verify_ip>, B<-verify_name>, B<-x509_strict> | |
e5fa864f DSH |
323 | |
324 | Set various options of certificate chain verification. See | |
9b86974e | 325 | L<verify(1)> manual page for details. |
e5fa864f | 326 | |
e3775a33 DSH |
327 | =back |
328 | ||
329 | =head1 NOTES | |
330 | ||
331 | The MIME message must be sent without any blank lines between the | |
332 | headers and the output. Some mail programs will automatically add | |
333 | a blank line. Piping the mail directly to sendmail is one way to | |
334 | achieve the correct format. | |
335 | ||
3fc9635e | 336 | The supplied message to be signed or encrypted must include the |
60250017 | 337 | necessary MIME headers or many S/MIME clients won't display it |
3fc9635e DSH |
338 | properly (if at all). You can use the B<-text> option to automatically |
339 | add plain text headers. | |
340 | ||
e3775a33 DSH |
341 | A "signed and encrypted" message is one where a signed message is |
342 | then encrypted. This can be produced by encrypting an already signed | |
3fc9635e | 343 | message: see the examples section. |
e3775a33 DSH |
344 | |
345 | This version of the program only allows one signer per message but it | |
346 | will verify multiple signers on received messages. Some S/MIME clients | |
19d2bb57 | 347 | choke if a message contains multiple signers. It is possible to sign |
e3775a33 DSH |
348 | messages "in parallel" by signing an already signed message. |
349 | ||
3fc9635e DSH |
350 | The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME |
351 | clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7 | |
352 | encrypted data is used for other purposes. | |
353 | ||
d884c5ba DSH |
354 | The B<-resign> option uses an existing message digest when adding a new |
355 | signer. This means that attributes must be present in at least one existing | |
356 | signer using the same message digest or this operation will fail. | |
357 | ||
e4ef2e25 | 358 | The B<-stream> and B<-indef> options enable streaming I/O support. |
76b46e77 DSH |
359 | As a result the encoding is BER using indefinite length constructed encoding |
360 | and no longer DER. Streaming is supported for the B<-encrypt> operation and the | |
361 | B<-sign> operation if the content is not detached. | |
362 | ||
363 | Streaming is always used for the B<-sign> operation with detached data but | |
364 | since the content is no longer part of the PKCS#7 structure the encoding | |
365 | remains DER. | |
366 | ||
e3775a33 DSH |
367 | =head1 EXIT CODES |
368 | ||
369 | =over 4 | |
370 | ||
c8919dde | 371 | =item Z<>0 |
e3775a33 | 372 | |
3fc9635e | 373 | the operation was completely successfully. |
e3775a33 | 374 | |
c8919dde | 375 | =item Z<>1 |
e3775a33 DSH |
376 | |
377 | an error occurred parsing the command options. | |
378 | ||
c8919dde | 379 | =item Z<>2 |
e3775a33 DSH |
380 | |
381 | one of the input files could not be read. | |
382 | ||
c8919dde | 383 | =item Z<>3 |
e3775a33 DSH |
384 | |
385 | an error occurred creating the PKCS#7 file or when reading the MIME | |
386 | message. | |
387 | ||
c8919dde | 388 | =item Z<>4 |
e3775a33 DSH |
389 | |
390 | an error occurred decrypting or verifying the message. | |
391 | ||
c8919dde | 392 | =item Z<>5 |
e3775a33 | 393 | |
19d2bb57 | 394 | the message was verified correctly but an error occurred writing out |
e3775a33 DSH |
395 | the signers certificates. |
396 | ||
397 | =back | |
398 | ||
399 | =head1 EXAMPLES | |
400 | ||
3fc9635e DSH |
401 | Create a cleartext signed message: |
402 | ||
1675f6eb | 403 | openssl smime -sign -in message.txt -text -out mail.msg \ |
1bc74519 | 404 | -signer mycert.pem |
3fc9635e | 405 | |
0d638dc1 | 406 | Create an opaque signed message: |
3fc9635e | 407 | |
1675f6eb | 408 | openssl smime -sign -in message.txt -text -out mail.msg -nodetach \ |
1bc74519 | 409 | -signer mycert.pem |
3fc9635e DSH |
410 | |
411 | Create a signed message, include some additional certificates and | |
412 | read the private key from another file: | |
413 | ||
1675f6eb | 414 | openssl smime -sign -in in.txt -text -out mail.msg \ |
1bc74519 | 415 | -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem |
3fc9635e | 416 | |
d884c5ba DSH |
417 | Create a signed message with two signers: |
418 | ||
419 | openssl smime -sign -in message.txt -text -out mail.msg \ | |
1bc74519 | 420 | -signer mycert.pem -signer othercert.pem |
d884c5ba | 421 | |
3fc9635e DSH |
422 | Send a signed message under Unix directly to sendmail, including headers: |
423 | ||
1675f6eb | 424 | openssl smime -sign -in in.txt -text -signer mycert.pem \ |
1bc74519 RS |
425 | -from steve@openssl.org -to someone@somewhere \ |
426 | -subject "Signed message" | sendmail someone@somewhere | |
3fc9635e DSH |
427 | |
428 | Verify a message and extract the signer's certificate if successful: | |
429 | ||
430 | openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt | |
431 | ||
432 | Send encrypted mail using triple DES: | |
433 | ||
1675f6eb | 434 | openssl smime -encrypt -in in.txt -from steve@openssl.org \ |
1bc74519 RS |
435 | -to someone@somewhere -subject "Encrypted message" \ |
436 | -des3 user.pem -out mail.msg | |
3fc9635e DSH |
437 | |
438 | Sign and encrypt mail: | |
439 | ||
1675f6eb | 440 | openssl smime -sign -in ml.txt -signer my.pem -text \ |
1bc74519 RS |
441 | | openssl smime -encrypt -out mail.msg \ |
442 | -from steve@openssl.org -to someone@somewhere \ | |
443 | -subject "Signed and Encrypted message" -des3 user.pem | |
3fc9635e | 444 | |
d884c5ba DSH |
445 | Note: the encryption command does not include the B<-text> option because the |
446 | message being encrypted already has MIME headers. | |
3fc9635e DSH |
447 | |
448 | Decrypt mail: | |
449 | ||
450 | openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem | |
451 | ||
fd13f0ee DSH |
452 | The output from Netscape form signing is a PKCS#7 structure with the |
453 | detached signature format. You can use this program to verify the | |
454 | signature by line wrapping the base64 encoded structure and surrounding | |
455 | it with: | |
456 | ||
a8c12555 DSH |
457 | -----BEGIN PKCS7----- |
458 | -----END PKCS7----- | |
fd13f0ee | 459 | |
1bc74519 | 460 | and using the command: |
fd13f0ee DSH |
461 | |
462 | openssl smime -verify -inform PEM -in signature.pem -content content.txt | |
463 | ||
0d638dc1 | 464 | Alternatively you can base64 decode the signature and use: |
fd13f0ee DSH |
465 | |
466 | openssl smime -verify -inform DER -in signature.der -content content.txt | |
467 | ||
f3dea9a5 BM |
468 | Create an encrypted message using 128 bit Camellia: |
469 | ||
470 | openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem | |
471 | ||
d884c5ba DSH |
472 | Add a signer to an existing message: |
473 | ||
474 | openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg | |
475 | ||
3fc9635e DSH |
476 | =head1 BUGS |
477 | ||
d884c5ba DSH |
478 | The MIME parser isn't very clever: it seems to handle most messages that I've |
479 | thrown at it but it may choke on others. | |
3fc9635e | 480 | |
d884c5ba DSH |
481 | The code currently will only write out the signer's certificate to a file: if |
482 | the signer has a separate encryption certificate this must be manually | |
483 | extracted. There should be some heuristic that determines the correct | |
484 | encryption certificate. | |
3fc9635e | 485 | |
d884c5ba DSH |
486 | Ideally a database should be maintained of a certificates for each email |
487 | address. | |
3fc9635e DSH |
488 | |
489 | The code doesn't currently take note of the permitted symmetric encryption | |
7e0de9e8 | 490 | algorithms as supplied in the SMIMECapabilities signed attribute. This means the |
3fc9635e DSH |
491 | user has to manually include the correct encryption algorithm. It should store |
492 | the list of permitted ciphers in a database and only use those. | |
493 | ||
494 | No revocation checking is done on the signer's certificate. | |
495 | ||
496 | The current code can only handle S/MIME v2 messages, the more complex S/MIME v3 | |
497 | structures may cause parsing errors. | |
e3775a33 | 498 | |
d884c5ba DSH |
499 | =head1 HISTORY |
500 | ||
501 | The use of multiple B<-signer> options and the B<-resign> command were first | |
fb552ac6 | 502 | added in OpenSSL 1.0.0 |
d884c5ba | 503 | |
fa7b0111 | 504 | The -no_alt_chains options was first added to OpenSSL 1.1.0. |
d884c5ba | 505 | |
e2f92610 RS |
506 | =head1 COPYRIGHT |
507 | ||
508 | Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. | |
509 | ||
510 | Licensed under the OpenSSL license (the "License"). You may not use | |
511 | this file except in compliance with the License. You can obtain a copy | |
512 | in the file LICENSE in the source distribution or at | |
513 | L<https://www.openssl.org/source/license.html>. | |
514 | ||
515 | =cut |