This is a text-only version of the following page on https://raymii.org: --- Title : OpenSSL: Manually verify a certificate against an OCSP Author : Remy van Elst Date : 07-04-2014 URL : https://raymii.org/s/articles/OpenSSL_Manually_Verify_a_certificate_against_an_OCSP.html Format : Markdown/HTML --- This article shows you how to manually verfify a certificate against an OCSP server. OCSP stands for the Online Certificate Status Protocol and is one way to validate a certificate status. It is an alternative to the CRL, certificate revocation list. Compared to CRL's: * Since an OCSP response contains less information than a typical CRL (certificate revocation list), OCSP can use networks and client resources more efficiently. * Using OCSP, clients do not need to parse CRLs themselves, saving client-side complexity. However, this is balanced by the practical need to maintain a cache. In practice, such considerations are of little consequence, since most applications rely on third-party libraries for all X.509 functions. * OCSP discloses to the responder that a particular network host used a particular certificate at a particular time. OCSP does not mandate encryption, so other parties may intercept this information. You can read more about the OCSP on [wikipedia][1]

Recently I removed all Google Ads from this site due to their invasive tracking, as well as Google Analytics. Please, if you found this content useful, consider a small donation using any of the options below:

I'm developing an open source monitoring app called Leaf Node Monitoring, for windows, linux & android. Go check it out!

Consider sponsoring me on Github. It means the world to me if you show your appreciation and you'll help pay the server costs.

You can also sponsor me by getting a Digital Ocean VPS. With this referral link you'll get $200 credit for 60 days. Spend $25 after your credit expires and I'll get $25!

If you want to verify a certificate against a CRL manually [you can read my article on that here][3]. We will be using OpenSSL in this article. I'm using the following version: $ openssl version OpenSSL 1.0.1g 7 Apr 2014 ### Get a certificate with an OCSP First we will need a certificate from a website. I'll be using Wikipedia as an example here. We can retreive this with the following openssl command: openssl s_client -connect wikipedia.org:443 2>&1 < /dev/null | sed -n '/-----BEGIN/,/-----END/p' Save this output to a file, for example, wikipedia.pem: openssl s_client -connect wikipedia.org:443 2>&1 < /dev/null | sed -n '/-----BEGIN/,/-----END/p' > wikipedia.pem Now, check if this certificate has an OCSP URI: openssl x509 -noout -ocsp_uri -in wikipedia.pem http://ocsp.digicert.com If it does not give any output, the certificate has no OCSP URI. You cannot valdiate it against an OCSP. ### Getting the certificate chain It is required to send the certificate chain along with the certificate you want to validate. So, we need to get the certificate chain for our domain, wikipedia.org. Using the `-showcerts` option with `openssl s_client`, we can see all the certificates, including the chain: openssl s_client -connect wikipedia.org:443 -showcerts 2>&1 < /dev/null Results in a boatload of output, but what we are interested in is the following: 1 s:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert High Assurance CA-3 i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert High Assurance EV Root CA -----BEGIN CERTIFICATE----- MIIGWDCCBUCgAwIBAgIQCl8RTQNbF5EX0u/UA4w/OzANBgkqhkiG9w0BAQUFADBs MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3 d3cuZGlnaWNlcnQuY29tMSswKQYDVQQDEyJEaWdpQ2VydCBIaWdoIEFzc3VyYW5j ZSBFViBSb290IENBMB4XDTA4MDQwMjEyMDAwMFoXDTIyMDQwMzAwMDAwMFowZjEL MAkGA1UEBhMCVVMxFTATBgNVBAoTDERpZ2lDZXJ0IEluYzEZMBcGA1UECxMQd3d3 LmRpZ2ljZXJ0LmNvbTElMCMGA1UEAxMcRGlnaUNlcnQgSGlnaCBBc3N1cmFuY2Ug Q0EtMzCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAL9hCikQH17+NDdR CPge+yLtYb4LDXBMUGMmdRW5QYiXtvCgFbsIYOBC6AUpEIc2iihlqO8xB3RtNpcv KEZmBMcqeSZ6mdWOw21PoF6tvD2Rwll7XjZswFPPAAgyPhBkWBATaccM7pxCUQD5 BUTuJM56H+2MEb0SqPMV9Bx6MWkBG6fmXcCabH4JnudSREoQOiPkm7YDr6ictFuf 1EutkozOtREqqjcYjbTCuNhcBoz4/yO9NV7UfD5+gw6RlgWYw7If48hl66l7XaAs zPw82W3tzPpLQ4zJ1LilYRyyQLYoEt+5+F/+07LJ7z20Hkt8HEyZNp496+ynaF4d 32duXvsCAwEAAaOCAvowggL2MA4GA1UdDwEB/wQEAwIBhjCCAcYGA1UdIASCAb0w ggG5MIIBtQYLYIZIAYb9bAEDAAIwggGkMDoGCCsGAQUFBwIBFi5odHRwOi8vd3d3 LmRpZ2ljZXJ0LmNvbS9zc2wtY3BzLXJlcG9zaXRvcnkuaHRtMIIBZAYIKwYBBQUH AgIwggFWHoIBUgBBAG4AeQAgAHUAcwBlACAAbwBmACAAdABoAGkAcwAgAEMAZQBy AHQAaQBmAGkAYwBhAHQAZQAgAGMAbwBuAHMAdABpAHQAdQB0AGUAcwAgAGEAYwBj AGUAcAB0AGEAbgBjAGUAIABvAGYAIAB0AGgAZQAgAEQAaQBnAGkAQwBlAHIAdAAg AEMAUAAvAEMAUABTACAAYQBuAGQAIAB0AGgAZQAgAFIAZQBsAHkAaQBuAGcAIABQ AGEAcgB0AHkAIABBAGcAcgBlAGUAbQBlAG4AdAAgAHcAaABpAGMAaAAgAGwAaQBt AGkAdAAgAGwAaQBhAGIAaQBsAGkAdAB5ACAAYQBuAGQAIABhAHIAZQAgAGkAbgBj AG8AcgBwAG8AcgBhAHQAZQBkACAAaABlAHIAZQBpAG4AIABiAHkAIAByAGUAZgBl AHIAZQBuAGMAZQAuMBIGA1UdEwEB/wQIMAYBAf8CAQAwNAYIKwYBBQUHAQEEKDAm MCQGCCsGAQUFBzABhhhodHRwOi8vb2NzcC5kaWdpY2VydC5jb20wgY8GA1UdHwSB hzCBhDBAoD6gPIY6aHR0cDovL2NybDMuZGlnaWNlcnQuY29tL0RpZ2lDZXJ0SGln aEFzc3VyYW5jZUVWUm9vdENBLmNybDBAoD6gPIY6aHR0cDovL2NybDQuZGlnaWNl cnQuY29tL0RpZ2lDZXJ0SGlnaEFzc3VyYW5jZUVWUm9vdENBLmNybDAfBgNVHSME GDAWgBSxPsNpA/i/RwHUmCYaCALvY2QrwzAdBgNVHQ4EFgQUUOpzidsp+xCPnuUB INTeeZlIg/cwDQYJKoZIhvcNAQEFBQADggEBAB7ipUiebNtTOA/vphoqrOIDQ+2a vD6OdRvw/S4iWawTwGHi5/rpmc2HCXVUKL9GYNy+USyS8xuRfDEIcOI3ucFbqL2j CwD7GhX9A61YasXHJJlIR0YxHpLvtF9ONMeQvzHB+LGEhtCcAarfilYGzjrpDq6X dF3XcZpCdF/ejUN83ulV7WkAywXgemFhM9EZTfkI7qA5xSU1tyvED7Ld8aW3DiTE JiiNeXf1L/BXunwH1OH8zVowV36GEEfdMR/X/KLCvzB8XSSq6PmuX2p0ws5rs0bY Ib4p1I5eFdZCSucyb6Sxa1GDWL4/bcf72gMhy2oWGU4K8K2Eyl2Us1p292E= -----END CERTIFICATE----- As you can see, this is number 1. Number 0 is the certificate for Wikipedia, we already have that. If your site has more certificates in its chain, you will see more here. Save them all, in the order OpenSSL sends them (as in, first the one which directly issued your server certificate, then the one that issues that certificate and so on, with the root or most-root at the end of the file) to a file, named `chain.pem`. ### Sending the OCSP request We now have all the data we need to do an OCSP request. Using the following Openssl command we can send an OCSP request and only get the text output: openssl ocsp -issuer chain.pem -cert wikipedia.pem -text -url http://ocsp.digicert.com Results in: OCSP Request Data: Version: 1 (0x0) Requestor List: Certificate ID: Hash Algorithm: sha1 Issuer Name Hash: ED48ADDDCB7B00E20E842AA9B409F1AC3034CF96 Issuer Key Hash: 50EA7389DB29FB108F9EE50120D4DE79994883F7 Serial Number: 0114195F66FAFF8FD66E12496E516F4F Request Extensions: OCSP Nonce: 0410DA634F2ADC31DC48AE89BE64E8252D12 OCSP Response Data: OCSP Response Status: successful (0x0) Response Type: Basic OCSP Response Version: 1 (0x0) Responder Id: 50EA7389DB29FB108F9EE50120D4DE79994883F7 Produced At: Apr 9 08:45:00 2014 GMT Responses: Certificate ID: Hash Algorithm: sha1 Issuer Name Hash: ED48ADDDCB7B00E20E842AA9B409F1AC3034CF96 Issuer Key Hash: 50EA7389DB29FB108F9EE50120D4DE79994883F7 Serial Number: 0114195F66FAFF8FD66E12496E516F4F Cert Status: good This Update: Apr 9 08:45:00 2014 GMT Next Update: Apr 16 09:00:00 2014 GMT Signature Algorithm: sha1WithRSAEncryption 56:21:4c:dc:84:21:f7:a8:ac:a7:b9:bc:10:19:f8:19:f1:34: c1:63:ca:14:7f:8f:5a:85:2a:cc:02:b0:f8:b5:05:4a:0f:28: 50:2a:4a:4d:04:01:b5:05:ef:a5:88:41:d8:9d:38:00:7d:76: 1a:aa:ff:21:50:68:90:d2:0c:93:85:49:e7:8e:f1:58:08:77: a0:4e:e2:22:98:01:b7:e3:27:75:11:f5:b7:8f:e0:75:7d:19: 9b:74:cf:05:dc:ae:1c:36:09:95:b6:08:bc:e7:3f:ea:a2:e3: ae:d7:8f:c0:9d:8e:c2:37:67:c7:5b:d8:b0:67:23:f1:51:53: 26:c2:96:b0:1a:df:4e:fb:4e:e3:da:a3:98:26:59:a8:d7:17: 69:87:a3:68:47:08:92:d0:37:04:6b:49:9a:96:9d:9c:b1:e8: cb:dc:68:7b:4a:4d:cb:08:f7:92:67:41:99:b6:54:56:80:0c: 18:a7:24:53:ac:c6:da:1f:4d:f4:3c:7d:68:44:1d:a4:df:1d: 48:07:85:52:86:59:46:d1:35:45:1a:c7:6b:6b:92:de:24:ae: c0:97:66:54:29:7a:c6:86:a6:da:9f:06:24:dc:ac:80:66:95: e0:eb:49:fd:fb:d4:81:6a:2b:81:41:57:24:78:3b:e0:66:70: d4:2e:52:92 wikipedia.pem: good This Update: Apr 9 08:45:00 2014 GMT Next Update: Apr 16 09:00:00 2014 GMT If you want to have a more summarized output, leave out the `-text` option. I most of the time include it to find out problems with an OCSP. This is how a good certificate status looks: openssl ocsp -issuer chain.pem -cert wikipedia.pem -url http://ocsp.digicert.com wikipedia.pem: good This Update: Apr 9 08:45:00 2014 GMT Next Update: Apr 16 09:00:00 2014 GMT ### Revoked certificate If you have a revoked certificate, you can also test it the same way as stated above. The response looks like this: Response verify OK test-revoked.pem: revoked This Update: Apr 9 03:02:45 2014 GMT Next Update: Apr 10 03:02:45 2014 GMT Revocation Time: Mar 25 15:45:55 2014 GMT You can test this using the certificate and chain on the Verisign revoked certificate test page: ### Other errors If we send this request to another OCSP, one who did not issued this certificate, we should receive an unauthorized error: openssl ocsp -issuer chain.pem -cert wikipedia.pem -url http://rapidssl-ocsp.geotrust.com Responder Error: unauthorized (6) The `-text` option here shows more information: OCSP Request Data: Version: 1 (0x0) Requestor List: Certificate ID: Hash Algorithm: sha1 Issuer Name Hash: ED48ADDDCB7B00E20E842AA9B409F1AC3034CF96 Issuer Key Hash: 50EA7389DB29FB108F9EE50120D4DE79994883F7 Serial Number: 0114195F66FAFF8FD66E12496E516F4F Request Extensions: OCSP Nonce: 041015BB718C43C46C41122E841DB2282ECE Responder Error: unauthorized (6) Some OCSP's are configured differently and give out this error: openssl ocsp -issuer chain.pem -cert wikipedia.pem -url http://ocsp.digidentity.eu/L4/services/ocsp Response Verify Failure 140735308649312:error:2706B06F:OCSP routines:OCSP_CHECK_IDS:response contains no revocation data:ocsp_vfy.c:269: 140735308649312:error:2706B06F:OCSP routines:OCSP_CHECK_IDS:response contains no revocation data:ocsp_vfy.c:269: wikipedia.pem: ERROR: No Status found. If we do include the `-text` option here we can see that a response is sent, however, that it has no data in it: OCSP Response Data: OCSP Response Status: successful (0x0) Response Type: Basic OCSP Response Version: 1 (0x0) Responder Id: C = NL, O = Digidentity B.V., CN = Digidentity OCSP Produced At: Apr 9 12:02:00 2014 GMT Responses: Response Extensions: OCSP Nonce: 0410EB540472EA2D8246E88F3317B014BEEF Signature Algorithm: sha256WithRSAEncryption Other OCSP's give out the "unknown" status: openssl ocsp -issuer chain.pem -cert wikipedia.pem -url http://ocsp.quovadisglobal.com/ Response Verify Failure 140735308649312:error:27069070:OCSP routines:OCSP_basic_verify:root ca not trusted:ocsp_vfy.c:152: wikipedia.pem: unknown This Update: Apr 9 12:09:18 2014 GMT The `-text` options shows us more: OCSP Response Data: OCSP Response Status: successful (0x0) Response Type: Basic OCSP Response Version: 1 (0x0) Responder Id: C = CH, O = QuoVadis Limited, OU = OCSP Responder, CN = QuoVadis OCSP Authority Signature Produced At: Apr 9 12:09:10 2014 GMT Responses: Certificate ID: Hash Algorithm: sha1 Issuer Name Hash: ED48ADDDCB7B00E20E842AA9B409F1AC3034CF96 Issuer Key Hash: 50EA7389DB29FB108F9EE50120D4DE79994883F7 Serial Number: 0114195F66FAFF8FD66E12496E516F4F Cert Status: unknown This Update: Apr 9 12:09:10 2014 GMT Response Extensions: ### Sources * * * [https://en.wikipedia.org/wiki/Online _Certificate_ Status_Protocol][1] [1]: https://en.wikipedia.org/wiki/Online_Certificate_Status_Protocol [2]: https://www.digitalocean.com/?refcode=7435ae6b8212 [3]: https://raymii.org/s/articles/OpenSSL_manually_verify_a_certificate_against_a_CRL.html --- License: All the text on this website is free as in freedom unless stated otherwise. This means you can use it in any way you want, you can copy it, change it the way you like and republish it, as long as you release the (modified) content under the same license to give others the same freedoms you've got and place my name and a link to this site with the article as source. This site uses Google Analytics for statistics and Google Adwords for advertisements. You are tracked and Google knows everything about you. Use an adblocker like ublock-origin if you don't want it. All the code on this website is licensed under the GNU GPL v3 license unless already licensed under a license which does not allows this form of licensing or if another license is stated on that page / in that software: This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . Just to be clear, the information on this website is for meant for educational purposes and you use it at your own risk. I do not take responsibility if you screw something up. Use common sense, do not 'rm -rf /' as root for example. If you have any questions then do not hesitate to contact me. See https://raymii.org/s/static/About.html for details.