swarmautomation.com
Issued by COMODO RSA Domain Validation Secure Server CA
About this certificate
This digital certificate with serial number 2d:8e:00:19:5a:b6:ec:9a:03:6a:a8:1e:ef:e0:f5:a3 was issued on by COMODO CA Limited.
With 2 subject alternative names this certificate can be used to secure multiple fqdn's. This certificate has already expired and will cause a warning or error message in the browser it's still listed on this site to allow you to look back on previously issued certificates. If we have found any compliance issues with this certificate they will be shown below. I hope this certificate review is providing you the detailed information in a simple form you where looking for.
We have idenified some issues with this certificate:
- Subscriber Certificate: commonName is deprecated. (BRs: 7.1.4.2.2)
Certificate Subject
CN=swarmautomation.com,OU=Domain Control Validated+OU=Hosted by Zen Internet LTD+OU=COMODO SSL
COMODO CA Limited
Organization:
COMODO CA Limited
State / Province:
Greater Manchester
Locality: Salford
Country: GB
Locality: Salford
Country: GB
This certificate has expire since
Certificate Details
Serial Number (hex): 2d:8e:00:19:5a:b6:ec:9a:03:6a:a8:1e:ef:e0:f5:a3Serial Number (int): 60552567973012015363156745293003814307
Serial Number lenght: 126 bits, 16 octets
SubjectKeyId: 61:5b:ee:3f:51:8d:85:7d:f6:0f:52:1c:c4:12:02:f5:8e:7f:ee:90
AuthorityKeyId: 90:af:6a:3a:94:5a:0b:d8:90:ea:12:56:73:df:43:b4:3a:28:da:e7
Fingerprint (sha1): 94:96:b8:47:42:36:bc:a0:3a:de:2c:21:19:09:5f:e7:49:6f:c1:16
Fingerprint (sha256): 3a:0c:57:d7:d5:a8:6a:9d:37:f1:1e:ad:d8:fc:43:fd:59:36:82:f2:06:1d:f3:aa:52:f9:6f:e3:5d:d8:3d:9e
Issuing Certificate URL: http://crt.comodoca.com/COMODORSADomainValidationSecureServerCA.crt
Revocation information
OCSP Server: http://ocsp.comodoca.comCRL Distribution Point: http://crl.comodoca.com/COMODORSADomainValidationSecureServerCA.crl
Check the revocation status for certificate swarmautomation.com
2
DNS Names
0
Email Addresses
0
IP Addresses
Advanced Certificate Properties
Tehnical certificate details for swarmautomation.com
Public Key Algorithm
RSA
Key Size
2048
Signature Algorithm
SHA256 with RSA
Key Usage
Digital Signature
Key Encipherment
Extended Key Usages
Server Authentication
Client Authentication
Extensions
9 extensions
No
unhandled critical extensions
CA Certificate
This is not a CA certificate
Subject Alternative Names
swarmautomation.com
www.swarmautomation.com
www.swarmautomation.com
Other certificates including the domain name swarmautomation.com
(limited to 100 certificates)
Certificate
The complete raw certificate details for swarmautomation.com in PEM and ASN.1 format.
Certificate (PEM)
-----BEGIN CERTIFICATE----- MIIFgTCCBGmgAwIBAgIQLY4AGVq27JoDaqge7+D1ozANBgkqhkiG9w0BAQsFADCB kDELMAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4G A1UEBxMHU2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxNjA0BgNV BAMTLUNPTU9ETyBSU0EgRG9tYWluIFZhbGlkYXRpb24gU2VjdXJlIFNlcnZlciBD QTAeFw0xNTEyMDQwMDAwMDBaFw0xNjEyMTYyMzU5NTlaMHsxITAfBgNVBAsTGERv bWFpbiBDb250cm9sIFZhbGlkYXRlZDEjMCEGA1UECxMaSG9zdGVkIGJ5IFplbiBJ bnRlcm5ldCBMVEQxEzARBgNVBAsTCkNPTU9ETyBTU0wxHDAaBgNVBAMTE3N3YXJt YXV0b21hdGlvbi5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCj n2mR2UETa9m18w7O/C9HztKuqR2lCq0RDsO5xxJ4x355fFqvpX0XOjhx5XnRzPe2 47oiOS5fdr9u/SyGBLujSfZRHm/eFWhOdLYE2+KMulHOhjk0fhIJ70tB0QsbSnFj lwk8sGGlIZjAwyQwY29FfFK3VQp/X8Yj/bVLzN/ScXsJr4lNVS9yaKi3WpPzlOK9 Z/1GMGweiFxlihiAPko73cCXJntjSs69QjrBtYwRTh6gK9PW5FVJ+JCAYm50lpcm cgAFOOeMJ+GlcZbagB4rKt7u578LCBWJwWQgFcbeb4oW/IKhkizTJsNkEkFIpfye tfKYulhKZZGJQYIExsApAgMBAAGjggHpMIIB5TAfBgNVHSMEGDAWgBSQr2o6lFoL 2JDqElZz30O0Oija5zAdBgNVHQ4EFgQUYVvuP1GNhX32D1IcxBIC9Y5/7pAwDgYD VR0PAQH/BAQDAgWgMAwGA1UdEwEB/wQCMAAwHQYDVR0lBBYwFAYIKwYBBQUHAwEG CCsGAQUFBwMCME8GA1UdIARIMEYwOgYLKwYBBAGyMQECAgcwKzApBggrBgEFBQcC ARYdaHR0cHM6Ly9zZWN1cmUuY29tb2RvLmNvbS9DUFMwCAYGZ4EMAQIBMFQGA1Ud HwRNMEswSaBHoEWGQ2h0dHA6Ly9jcmwuY29tb2RvY2EuY29tL0NPTU9ET1JTQURv bWFpblZhbGlkYXRpb25TZWN1cmVTZXJ2ZXJDQS5jcmwwgYUGCCsGAQUFBwEBBHkw dzBPBggrBgEFBQcwAoZDaHR0cDovL2NydC5jb21vZG9jYS5jb20vQ09NT0RPUlNB RG9tYWluVmFsaWRhdGlvblNlY3VyZVNlcnZlckNBLmNydDAkBggrBgEFBQcwAYYY aHR0cDovL29jc3AuY29tb2RvY2EuY29tMDcGA1UdEQQwMC6CE3N3YXJtYXV0b21h dGlvbi5jb22CF3d3dy5zd2FybWF1dG9tYXRpb24uY29tMA0GCSqGSIb3DQEBCwUA A4IBAQBVoFsnU7aZgXVPNRyHPSjVnUhq2fB9MvKw3oHdFB2nsiwANL/cZ/tXbNcL UInrlLUg0FR6SeJ64zrxcMIs9bXfikUNvKehe7UCV7ACBDU7aHIlSnGEUa5rQ6Ty x5C6JNI/+pOCukLvRCerF0ZitrlV4H/Swp/C9ZEm0iwWCNGujNIh3GccFF4/f/AD GIHs67yN96wyorCJR4sWuxzLzAweOF/iFfs6c9Uu+9H71CancsJmyre2lpkx/eEZ fihkbQKZvGfaHggFTt8SF1D/bbDD9TlWVLBj92gWb2xT/6lg+AK0bFHH2lkXoqXB mi1ltxzhSnfW0tHcW8lOrAI0xkqb -----END CERTIFICATE-----
Public Key (PEM)
-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAo59pkdlBE2vZtfMOzvwv R87SrqkdpQqtEQ7DuccSeMd+eXxar6V9Fzo4ceV50cz3tuO6IjkuX3a/bv0shgS7 o0n2UR5v3hVoTnS2BNvijLpRzoY5NH4SCe9LQdELG0pxY5cJPLBhpSGYwMMkMGNv RXxSt1UKf1/GI/21S8zf0nF7Ca+JTVUvcmiot1qT85TivWf9RjBsHohcZYoYgD5K O93AlyZ7Y0rOvUI6wbWMEU4eoCvT1uRVSfiQgGJudJaXJnIABTjnjCfhpXGW2oAe Kyre7ue/CwgVicFkIBXG3m+KFvyCoZIs0ybDZBJBSKX8nrXymLpYSmWRiUGCBMbA KQIDAQAB -----END PUBLIC KEY-----
ASN.1 decoded
[c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . [c:2|t:0|true] OtherName . . . . . . . . . . . . [c:0|t:2|false] INTEGER 2 . . . . . . . . [c:0|t:2|false] INTEGER 60552567973012015363156745293003814307 . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.2.840.113549.1.1.11 (sha256WithRSAEncryption) . . . . . . . . . . . . [c:0|t:5|false] NULL . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.6 (countryName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'GB' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.8 (stateOrProvinceName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Greater Manchester' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.7 (localityName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Salford' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.10 (organizationName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'COMODO CA Limited' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.3 (commonName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'COMODO RSA Domain Validation Secure Server CA' . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2015-12-04 00:00:00 +0000 UTC . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2016-12-16 23:59:59 +0000 UTC . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.11 (organizationalUnitName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Domain Control Validated' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.11 (organizationalUnitName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Hosted by Zen Internet LTD' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.11 (organizationalUnitName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'COMODO SSL' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.3 (commonName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'swarmautomation.com' . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.2.840.113549.1.1.1 (rsaEncryption) . . . . . . . . . . . . . . . . [c:0|t:5|false] NULL . . . . . . . . . . . . [c:0|t:3|false] BIT STRING (2160 bits) . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:2|false] INTEGER 20655452884699631546613992079505395423148227758574661711381812598642696471475071172128630250846520759222841433061297245349278809877101004602848345975090820157175429678331377657997898371464656545802922045269634046898215787116826610368008308736400581704775948862524880621320305503816910451260783659248253330832173244580586880080036547219933018209437062775539137598590701778032017977568480312293171264214779689871268557071411759415616010413604250367341037011851211842185040193340564993444778497923961943151707449169748199894005492990521536470994184727021556551711024357276988852668460555056505016318488788437337064783913 . . . . . . . . . . . . . . . . . . . . [c:0|t:2|false] INTEGER 65537 . . . . . . . . [c:2|t:3|true] ORAddress . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.35 (authorityKeyIdentifier) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (24 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|false] OtherName 90af6a3a945a0bd890ea125673df43b43a28dae7 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.14 (subjectKeyIdentifier) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (22 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (20 bytes) 615bee3f518d857df60f521cc41202f58e7fee90 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.15 (keyUsage) . . . . . . . . . . . . . . . . . . . . [c:0|t:1|false] BOOLEAN true . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (4 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:3|false] BIT STRING (3 bits) 05a0 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.19 (basicConstraints) . . . . . . . . . . . . . . . . . . . . [c:0|t:1|false] BOOLEAN true . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (2 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.37 (extKeyUsage) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (22 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.3.1 (serverAuth) . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.3.2 (clientAuth) . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.32 (certificatePolicies) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (72 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.4.1.6449.1.2.2.7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.2.1 (cps) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:22|false] IA5String 'https://secure.comodo.com/CPS' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.23.140.1.2.1 (Domain Validation Certificates Policy) . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.31 (cRLDistributionPoints) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (77 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|true] OtherName . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|true] OtherName . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:6|false] IA5String 'http://crl.comodoca.com/COMODORSADomainValidationSecureServerCA.crl' . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.1.1 (authorityInfoAccess) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (121 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.48.2 (caIssuers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:6|false] IA5String 'http://crt.comodoca.com/COMODORSADomainValidationSecureServerCA.crt' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.48.1 (ocsp) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:6|false] IA5String 'http://ocsp.comodoca.com' . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.17 (subjectAltName) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (48 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'swarmautomation.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.swarmautomation.com' . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.2.840.113549.1.1.11 (sha256WithRSAEncryption) . . . . . . . . [c:0|t:5|false] NULL . . . . [c:0|t:3|false] BIT STRING (2048 bits) 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