rdekor.com

Issued by cPanel, Inc. Certification Authority

About this certificate

This digital certificate with serial number a3:be:17:85:d2:c1:f2:2f:81:ae:eb:30:74:38:f2:84 was issued on by cPanel, Inc..

With 6 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=rdekor.com

cPanel, Inc.

Organization: cPanel, Inc.
State / Province: TX
Locality: Houston
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): a3:be:17:85:d2:c1:f2:2f:81:ae:eb:30:74:38:f2:84
Serial Number (int): 217651176814055721353016574507967115908
Serial Number lenght: 128 bits, 16 octets

SubjectKeyId: 82:b4:47:6e:43:ba:bd:46:30:42:4d:2c:03:7e:c1:bb:b0:49:63:a6
AuthorityKeyId: 7e:03:5a:65:41:6b:a7:7e:0a:e1:b8:9d:08:ea:1d:8e:1d:6a:c7:65

Fingerprint (sha1): 63:d4:00:06:40:13:b8:95:2c:36:fa:f4:a3:ba:fb:f9:59:b3:1c:1b
Fingerprint (sha256): c2:9d:0c:18:d7:81:1b:75:a5:95:0b:ae:40:42:4a:4d:e5:06:d9:b9:ac:a9:1d:ee:84:af:ef:8a:16:a7:a8:96

Issuing Certificate URL: http://crt.comodoca.com/cPanelIncCertificationAuthority.crt

Revocation information

OCSP Server: http://ocsp.comodoca.com
CRL Distribution Point: http://crl.comodoca.com/cPanelIncCertificationAuthority.crl

Check the revocation status for certificate rdekor.com

6

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for rdekor.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

rdekor.com
mail.rdekor.com
rdekor.rdekor.mycpanel.rs
webdisk.rdekor.com
www.rdekor.com
www.rdekor.rdekor.mycpanel.rs

Other certificates including the domain name rdekor.com

(limited to 100 certificates)
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.rdekor.mycpanel.rs
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com
rdekor.com

Certificate

The complete raw certificate details for rdekor.com in PEM and ASN.1 format.

Certificate (PEM)

-----BEGIN CERTIFICATE-----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==
-----END CERTIFICATE-----

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAzTv1YXh4jfF0F+MoqTUZ
72m0onsZ02dYUSxyAaYhx7tPjuPGzHGL2CkE7dLNzVrPIwe+ybv3FVANdhMaPCD1
1oVabdw5QLd/9LWq0/Q5Dw1bqaUUrsY7q39cjPPmzeMaqnJ0LitL6QUgXYE46LDD
BvOSIz6JOm306uKamYteClbafLKTmMZKLHhbEYP0FcEUqKAOVb4+HCTxPFnHWJ0f
3KAMeZ/74bFwWH3GViIoBnFPmFq7d6HLXNJ0g0mxuy8/xcvk3/6qKEhHUg5dPNpp
XbQhOaL3cww7dOsHm+6b3DTcxkiIpaYZ1aQej+pnBv4fpO30KuJqjcOZPl3K9l5Y
+wIDAQAB
-----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 217651176814055721353016574507967115908
 . . . . . . . . [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 'US'
 . . . . . . . . . . . . [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 'TX'
 . . . . . . . . . . . . [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 'Houston'
 . . . . . . . . . . . . [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 'cPanel, Inc.'
 . . . . . . . . . . . . [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 'cPanel, Inc. Certification Authority'
 . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2017-04-14 00:00:00 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2017-07-13 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 2.5.4.3 (commonName)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'rdekor.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 25908419165494762829041145971374312516811167623097966961030827473263068479560614660527586612622391809855507903988018481395372691726357015209119306141893474876841557370308255245537237724913321952534898045591475205334318430642849061914514638167643357207339571760712959193617671470753328836585403578847028114103446388077938013983470737634402482529328028142505218508052422780526520994456838617687115374632597211165514728618043705806050722988993498343836027741966268573616311586509814814011399507022612423638768089615543233132795281201049567407795720838918201160797190433974391859571556184955121268059651044128328087656699
 . . . . . . . . . . . . . . . . . . . . [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 7e035a65416ba77e0ae1b89d08ea1d8e1d6ac765
 . . . . . . . . . . . . . . . . [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)
							82b4476e43babd4630424d2c037ec1bbb04963a6
 . . . . . . . . . . . . . . . . [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 1.3.6.1.4.1.6449.1.2.2.52
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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 (69 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/cPanelIncCertificationAuthority.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 (113 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/cPanelIncCertificationAuthority.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 (125 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'rdekor.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'mail.rdekor.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'rdekor.rdekor.mycpanel.rs'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'webdisk.rdekor.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.rdekor.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.rdekor.rdekor.mycpanel.rs'
 . . . . [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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