www.dongseocp.or.kr

Issued by EssentialSSL CA

About this certificate


This digital certificate with serial number c3:e9:fa:1d:44:7f:4d:d6:26:43:bf:ef:5f:c5:b0:d8 was issued on by COMODO CA Limited .

With 2 subject alternative names this certificate can be used to secure multiple fqdn's. While the 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.

Cerificate errors/warnings *beta

  • ERROR: Certificate contains a key usage different from ServerAuth, ClientAuth or ServerGatedCrypto

www.dongseocp.or.kr

Organization unit: Domain Control Validated
Organization unit: Hosted by Korea Information Certificate Authority, Inc.
Organization unit: EssentialSSL

COMODO CA Limited

Organization: COMODO CA Limited

Time since certificate expired

This certificate has expire since

Certificate Details

Serial Number (hex): c3:e9:fa:1d:44:7f:4d:d6:26:43:bf:ef:5f:c5:b0:d8
Serial Number (int): 260414337267313717704483953171675590872
Serial Number lenght: 128 bits, 16 octets

SubjectKeyId: 3e:6a:3f:f7:6a:48:84:7a:7f:e4:3f:b6:a3:03:b5:d1:fc:96:78:e6
AuthorityKeyId: da:cb:ea:ad:5b:08:5d:cc:ff:fc:26:54:ce:49:e5:55:c6:38:f4:f8

Fingerprint (sha1): 9b:91:57:5f:58:9c:95:97:4d:9f:12:19:72:67:c7:be:95:13:82:84
Fingerprint (sha256): fb:cd:f3:8c:95:db:96:27:39:c5:32:7e:22:bc:57:4f:71:4b:df:93:9a:4d:54:4f:ba:9d:6e:5a:7e:d8:bc:b8

Issuing Certificate URL: http://crt.comodoca.com/EssentialSSLCA_2.crt

Revocation information

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

Check the revocation status for the current certificate on www.dongseocp.or.kr
2
DNS Names
0
Email Addresses
0
IP Addresses

Advanced Certificate Properties

Technical details about this certificate


Public Key Algorithm

RSA

Key Size

2048

Signature Algorithm

SHA1 with RSA



Key Usage

Digital Signature
Key Encipherment

Extended Key Usages

Server Authentication
Client Authentication
Microsoft Server-Gated Cryptography
Netscape Server-Gated Cryptography

Extensions

9 extensions
No unhandled critical extensions



CA Certificate

This is not a CA certificate

Subject Alternative Names

www.dongseocp.or.kr
dongseocp.or.kr

Certificate

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

Certificate (PEM)

-----BEGIN CERTIFICATE----- MIIFYTCCBEmgAwIBAgIRAMPp+h1Ef03WJkO/71/FsNgwDQYJKoZIhvcNAQEFBQAw cjELMAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4G A1UEBxMHU2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxGDAWBgNV BAMTD0Vzc2VudGlhbFNTTCBDQTAeFw0xMzA3MDQwMDAwMDBaFw0xNDA3MDQyMzU5 NTlaMIGaMSEwHwYDVQQLExhEb21haW4gQ29udHJvbCBWYWxpZGF0ZWQxQDA+BgNV BAsTN0hvc3RlZCBieSBLb3JlYSBJbmZvcm1hdGlvbiBDZXJ0aWZpY2F0ZSBBdXRo b3JpdHksIEluYy4xFTATBgNVBAsTDEVzc2VudGlhbFNTTDEcMBoGA1UEAxMTd3d3 LmRvbmdzZW9jcC5vci5rcjCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEB AMxToSGvOqb/DGs3swi6EQkkTW+NM/0NG7qDkhyE3lbR1BuV/rcdQ12Y0KDXjgIn UolfESE8Yt1MaibP0usxi7klT+HCKF3NrzR8wMcFnNjThoNmiubiFYKn6P1iTg3T M8RNfwhbj8BdpEP2tiuM65mLWvmeaIt02gT7z6DQAEEC0dwBEVDdsFNzX+GHqfSc 4bth4siCOg4HMllZLiscvvyJb5s4/ZuoVkCzgiYlPpS+7d6XYD1J5hZuRQS1sXvX oamHtZX3PxMZcyeIoQVImg5tunDsfBETap114xDmLpGt88mdi2w/M7CO0lP1ahxB kVKtBHD2QY8Ku3aRCrWt1wECAwEAAaOCAccwggHDMB8GA1UdIwQYMBaAFNrL6q1b CF3M//wmVM5J5VXGOPT4MB0GA1UdDgQWBBQ+aj/3akiEen/kP7ajA7XR/JZ45jAO BgNVHQ8BAf8EBAMCBaAwDAYDVR0TAQH/BAIwADA0BgNVHSUELTArBggrBgEFBQcD AQYIKwYBBQUHAwIGCisGAQQBgjcKAwMGCWCGSAGG+EIEATBPBgNVHSAESDBGMDoG CysGAQQBsjEBAgIHMCswKQYIKwYBBQUHAgEWHWh0dHBzOi8vc2VjdXJlLmNvbW9k by5jb20vQ1BTMAgGBmeBDAECATA7BgNVHR8ENDAyMDCgLqAshipodHRwOi8vY3Js LmNvbW9kb2NhLmNvbS9Fc3NlbnRpYWxTU0xDQS5jcmwwbgYIKwYBBQUHAQEEYjBg MDgGCCsGAQUFBzAChixodHRwOi8vY3J0LmNvbW9kb2NhLmNvbS9Fc3NlbnRpYWxT U0xDQV8yLmNydDAkBggrBgEFBQcwAYYYaHR0cDovL29jc3AuY29tb2RvY2EuY29t MC8GA1UdEQQoMCaCE3d3dy5kb25nc2VvY3Aub3Iua3KCD2RvbmdzZW9jcC5vci5r cjANBgkqhkiG9w0BAQUFAAOCAQEAhJbYfCXO0wvuYK7kzhpSa4WMgLtVF122sLC2 gDpfAOsWumkZymdmSxyd3rTH9rAIQ6x0smVG5ICkonZAsuT3JQHAwhYAWPYcq8DV /s/rIYloYdehHYCIM0CwvR8PO0hoamlZ8lHQp0aihoosVrN/IE3dm0Ylfen49g+1 MUNmZuiPaC0isYWFfrk1h0bxp5EUK6kChB0r5XlrESSZMaDFq+/Yp9eCUvhmYMqM 7cQif5aau6ytY0lH6aX9GvRTaaAk0IaQIGDzCWz5QyqycWtAn8SYtb8YEH0XEXYY UTELPKPvXPZHlVSeOuJ/IzPRnWI1kOrPAWl+slputFwVDIWsKg== -----END CERTIFICATE-----

Public Key (PEM)

-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAzFOhIa86pv8MazezCLoR CSRNb40z/Q0buoOSHITeVtHUG5X+tx1DXZjQoNeOAidSiV8RITxi3UxqJs/S6zGL uSVP4cIoXc2vNHzAxwWc2NOGg2aK5uIVgqfo/WJODdMzxE1/CFuPwF2kQ/a2K4zr mYta+Z5oi3TaBPvPoNAAQQLR3AERUN2wU3Nf4Yep9Jzhu2HiyII6DgcyWVkuKxy+ /Ilvmzj9m6hWQLOCJiU+lL7t3pdgPUnmFm5FBLWxe9ehqYe1lfc/ExlzJ4ihBUia Dm26cOx8ERNqnXXjEOYuka3zyZ2LbD8zsI7SU/VqHEGRUq0EcPZBjwq7dpEKta3X AQIDAQAB -----END PUBLIC KEY-----

ASN1 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 260414337267313717704483953171675590872 . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.2.840.113549.1.1.5 (sha1WithRSAEncryption) . . . . . . . . . . . . [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 'EssentialSSL CA' . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2013-07-04 00:00:00 +0000 UTC . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2014-07-04 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 Korea Information Certificate Authority, Inc.' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.11 (organizationalUnitName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'EssentialSSL' . . . . . . . . . . . . [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 'www.dongseocp.or.kr' . . . . . . . . [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 25793853417199781166800118314338177350473537130746591132979144127731010104721355086629204516288368783508912308408569208010696536747541450926388659879621177942940389297538002468347812263816600295169108563805893337453696419064573902103505265094262716673169231308834271905295303283979752414299187947375020993707838955135142332515455760010026383237028277870239465609542664461307033530121428916898794074057162695498599730162420854059642513697588154876779858229124529355700238037395471678361290963448374011366129050426948136174758552340668699058597826748028180681016615637441881169748904882808982115798940836517125882238721 . . . . . . . . . . . . . . . . . . . . [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 dacbeaad5b085dccfffc2654ce49e555c638f4f8 . . . . . . . . . . . . . . . . [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) 3e6a3ff76a48847a7fe43fb6a303b5d1fc9678e6 . . . . . . . . . . . . . . . . [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 (45 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:6|false] OBJECT IDENTIFIER 1.3.6.1.4.1.311.10.3.3 (serverGatedCrypto) . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.16.840.1.113730.4.1 (serverGatedCrypto) . . . . . . . . . . . . . . . . [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 (52 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/EssentialSSLCA.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 (98 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/EssentialSSLCA_2.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 (40 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.dongseocp.or.kr' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'dongseocp.or.kr' . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.2.840.113549.1.1.5 (sha1WithRSAEncryption) . . . . . . . . [c:0|t:5|false] NULL . . . . [c:0|t:3|false] BIT STRING (2048 bits) 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