DNS
THE CERTIFICATE BEHIND THE CONNECTION

TLS certificate checker.

Inspect SSL/TLS certificates for any public domain or subdomain.

Checks HTTPS on port 443, including subject alternative names, validity dates and the presented chain.

SSL certificate

TLSv1.3

kt.co.kr · 14.63.149.119:443

Unverified
Certificate verification failed. These are unverified certificate details presented by the server. Peer certificate CN=`cfm.kt.com' did not match expected CN=`kt.co.kr'

Certificate verification failed

Subject
C=KR ST=Gyeonggi-do O=KT Corporation CN=cfm.kt.com
Issuer
C=GB ST=Greater Manchester L=Salford O=Sectigo Limited CN=Sectigo RSA Organization Validation Secure Server CA
Valid from
2025-10-21T00:00:00+00:00
Expires
2026-11-21T23:59:59+00:00
Days remaining
60
Serial (hex)
126AF52E0B4638C751A31888D40B7FEA
Signature
RSA-SHA256
Public key
RSA 2048

Subject alternative names (SAN)

DNS:cfm.kt.com, DNS:www.cfm.kt.com

SHA-256 fingerprint

85:5A:4D:CC:07:34:62:78:21:D7:74:0A:19:9E:78:B9:A5:B8:6E:A9:7B:D0:C2:73:36:85:EA:E4:E7:1D:7D:94
Certificate extensions & PEM
authorityKeyIdentifier
17:D9:D6:25:27:67:F9:31:C2:49:43:D9:30:36:44:8C:6C:A9:4F:EB
subjectKeyIdentifier
0C:28:A6:72:CC:6E:86:CF:65:2A:EF:28:94:41:94:42:01:A3:B4:46
keyUsage
Digital Signature, Key Encipherment
basicConstraints
CA:FALSE
extendedKeyUsage
TLS Web Server Authentication, TLS Web Client Authentication
certificatePolicies
Policy: 1.3.6.1.4.1.6449.1.2.1.3.4 CPS: https://sectigo.com/CPS Policy: 2.23.140.1.2.2
crlDistributionPoints
Full Name: URI:http://crl.sectigo.com/SectigoRSAOrganizationValidationSecureServerCA.crl
authorityInfoAccess
CA Issuers - URI:http://crt.sectigo.com/SectigoRSAOrganizationValidationSecureServerCA.crt OCSP - URI:http://ocsp.sectigo.com
subjectAltName
DNS:cfm.kt.com, DNS:www.cfm.kt.com
ct_precert_scts
Signed Certificate Timestamp: Version : v1 (0x0) Log ID : D8:09:55:3B:94:4F:7A:FF:C8:16:19:6F:94:4F:85:AB: B0:F8:FC:5E:87:55:26:0F:15:D1:2E:72:BB:45:4B:14 Timestamp : Oct 21 02:01:10.094 2025 GMT Extensions: none Signature : ecdsa-with-SHA256 30:44:02:20:7E:F1:A6:E6:0C:CC:81:2F:0D:61:0E:C9: 71:18:0E:85:1C:D2:09:B6:30:3E:F0:CE:BD:1B:86:5D: D9:29:A3:0D:02:20:22:DD:F9:96:03:BF:F6:AA:54:87: B1:AB:16:34:A6:96:2B:F9:56:D8:F7:BB:3C:21:BB:12: B6:32:EE:E6:D9:49 Signed Certificate Timestamp: Version : v1 (0x0) Log ID : AF:67:88:3B:57:B0:4E:DD:8F:A6:D9:7E:F6:2E:A8:EB: 81:0A:C7:71:60:F0:24:5E:55:D6:0C:2F:E7:85:87:3A Timestamp : Oct 21 02:01:10.198 2025 GMT Extensions: none Signature : ecdsa-with-SHA256 30:44:02:20:1F:9F:FD:C8:90:1B:66:E5:4B:62:D8:10: C3:AE:6F:88:76:E8:83:43:30:57:45:56:46:24:3D:4C: 71:0A:96:E9:02:20:7A:61:32:FF:05:1D:D9:16:3D:3D: 21:4B:E8:2D:9E:01:CC:6B:E5:2C:22:A9:0E:9C:C4:EE: 43:9E:62:8D:BE:54 Signed Certificate Timestamp: Version : v1 (0x0) Log ID : AC:AB:30:70:6C:EB:EC:84:31:F4:13:D2:F4:91:5F:11: 1E:42:24:43:B1:F2:A6:8C:4F:3C:2B:3B:A7:1E:02:C3 Timestamp : Oct 21 02:01:10.230 2025 GMT Extensions: none Signature : ecdsa-with-SHA256 30:45:02:21:00:DC:A9:20:7B:F7:75:23:6A:56:C8:41: C7:0F:40:7A:0D:8A:65:3F:B3:CB:E8:88:94:03:90:B0: 59:F0:E6:83:D4:02:20:25:77:A4:62:36:A1:EE:93:B4: DF:C7:E0:E3:90:EF:F4:B4:01:3B:CC:2A:C2:0E:C2:43: 44:63:12:0A:2C:A8:07
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Cipher: TLS_AES_128_GCM_SHA256 · Checked 2026-09-22T19:33:24+00:00

Server-presented chain · 2 additional certificates

Chain certificate 1

Subject
C=GB ST=Greater Manchester L=Salford O=Sectigo Limited CN=Sectigo RSA Organization Validation Secure Server CA
Issuer
C=US ST=New Jersey L=Jersey City O=The USERTRUST Network CN=USERTrust RSA Certification Authority
Valid from
2018-11-02T00:00:00+00:00
Expires
2030-12-31T23:59:59+00:00
Days remaining
1561
Serial (hex)
137D539CAA7C31A9A433701968847A8D
Signature
RSA-SHA384
Public key
RSA 2048

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

72:A3:4A:C2:B4:24:AE:D3:F6:B0:B0:47:55:B8:8C:C0:27:DC:CC:80:6F:DD:B2:2B:4C:D7:C4:77:73:97:3E:C0
Certificate extensions & PEM
authorityKeyIdentifier
53:79:BF:5A:AA:2B:4A:CF:54:80:E1:D8:9B:C0:9D:F2:B2:03:66:CB
subjectKeyIdentifier
17:D9:D6:25:27:67:F9:31:C2:49:43:D9:30:36:44:8C:6C:A9:4F:EB
keyUsage
Digital Signature, Certificate Sign, CRL Sign
basicConstraints
CA:TRUE, pathlen:0
extendedKeyUsage
TLS Web Server Authentication, TLS Web Client Authentication
certificatePolicies
Policy: X509v3 Any Policy Policy: 2.23.140.1.2.2
crlDistributionPoints
Full Name: URI:http://crl.usertrust.com/USERTrustRSACertificationAuthority.crl
authorityInfoAccess
CA Issuers - URI:http://crt.usertrust.com/USERTrustRSAAddTrustCA.crt OCSP - URI:http://ocsp.usertrust.com
-----BEGIN CERTIFICATE-----
MIIGGTCCBAGgAwIBAgIQE31TnKp8MamkM3AZaIR6jTANBgkqhkiG9w0BAQwFADCB
iDELMAkGA1UEBhMCVVMxEzARBgNVBAgTCk5ldyBKZXJzZXkxFDASBgNVBAcTC0pl
cnNleSBDaXR5MR4wHAYDVQQKExVUaGUgVVNFUlRSVVNUIE5ldHdvcmsxLjAsBgNV
BAMTJVVTRVJUcnVzdCBSU0EgQ2VydGlmaWNhdGlvbiBBdXRob3JpdHkwHhcNMTgx
MTAyMDAwMDAwWhcNMzAxMjMxMjM1OTU5WjCBlTELMAkGA1UEBhMCR0IxGzAZBgNV
BAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEYMBYGA1UE
ChMPU2VjdGlnbyBMaW1pdGVkMT0wOwYDVQQDEzRTZWN0aWdvIFJTQSBPcmdhbml6
YXRpb24gVmFsaWRhdGlvbiBTZWN1cmUgU2VydmVyIENBMIIBIjANBgkqhkiG9w0B
AQEFAAOCAQ8AMIIBCgKCAQEAnJMCRkVKUkiS/FeN+S3qU76zLNXYqKXsW2kDwB0Q
9lkz3v4HSKjojHpnSvH1jcM3ZtAykffEnQRgxLVK4oOLp64m1F06XvjRFnG7ir1x
on3IzqJgJLBSoDpFUd54k2xiYPHkVpy3O/c8Vdjf1XoxfDV/ElFw4Sy+BKzL+k/h
fGVqwECn2XylY4QZ4ffK76q06Fha2ZnjJt+OErK43DOyNtoUHZZYQkBuCyKFHFEi
rsTIBkVtkuZntxkj5Ng2a4XQf8dS48+wdQHgibSov4o2TqPgbOuEQc6lL0giE5dQ
YkUeCaXMn2xXcEAG2yDoG9bzk4unMp63RBUJ16/9fAEc2wIDAQABo4IBbjCCAWow
HwYDVR0jBBgwFoAUU3m/WqorSs9UgOHYm8Cd8rIDZsswHQYDVR0OBBYEFBfZ1iUn
Z/kxwklD2TA2RIxsqU/rMA4GA1UdDwEB/wQEAwIBhjASBgNVHRMBAf8ECDAGAQH/
AgEAMB0GA1UdJQQWMBQGCCsGAQUFBwMBBggrBgEFBQcDAjAbBgNVHSAEFDASMAYG
BFUdIAAwCAYGZ4EMAQICMFAGA1UdHwRJMEcwRaBDoEGGP2h0dHA6Ly9jcmwudXNl
cnRydXN0LmNvbS9VU0VSVHJ1c3RSU0FDZXJ0aWZpY2F0aW9uQXV0aG9yaXR5LmNy
bDB2BggrBgEFBQcBAQRqMGgwPwYIKwYBBQUHMAKGM2h0dHA6Ly9jcnQudXNlcnRy
dXN0LmNvbS9VU0VSVHJ1c3RSU0FBZGRUcnVzdENBLmNydDAlBggrBgEFBQcwAYYZ
aHR0cDovL29jc3AudXNlcnRydXN0LmNvbTANBgkqhkiG9w0BAQwFAAOCAgEAThNA
lsnD5m5bwOO69Bfhrgkfyb/LDCUW8nNTs3Yat6tIBtbNAHwgRUNFbBZaGxNh10m6
pAKkrOjOzi3JKnSj3N6uq9BoNviRrzwB93fVC8+Xq+uH5xWo+jBaYXEgscBDxLmP
bYox6xU2JPti1Qucj+lmveZhUZeTth2HvbC1bP6mESkGYTQxMD0gJ3NR0N6Fg9N3
OSBGltqnxloWJ4Wyz04PToxcvr44APhL+XJ71PJ616IphdAEutNCLFGIUi7RPSRn
R+xVzBv0yjTqJsHe3cQhifa6ezIejpZehEU4z4CqN2mLYBd0FUiRnG3wTqN3yhsc
SPr5z0noX0+FCuKPkBurcEya67emP7SsXaRfz+bYipaQ908mgWB2XQ8kd5GzKjGf
FlqyXYwcKapInI5v03hAcNt37N3j0VcFcC3mSZiIBYRiBXBWdoY5TtMibx3+bfEO
s2LEPMvAhblhHrrhFYBZlAyuBbuMf1a+HNJav5fyakywxnB2sJCNwQs2uRHY1ihc
6k/+JLcYCpsM0MF8XPtpvcyiTcaQvKZN8rG61ppnW5YCUtCC+cQKXA0o4D/I+pWV
idWkvklsQLI+qGu41SWyxP7x09fn1txDAXYw+zuLXfdKiXyaNb78yvBXAfCNP6CH
MntHWpdLgtJmwsQt6j8k9Kf5qLnjatkYYaA7jBU=
-----END CERTIFICATE-----

Chain certificate 2

Subject
C=US ST=New Jersey L=Jersey City O=The USERTRUST Network CN=USERTrust RSA Certification Authority
Issuer
C=US ST=New Jersey L=Jersey City O=The USERTRUST Network CN=USERTrust RSA Certification Authority
Valid from
2010-02-01T00:00:00+00:00
Expires
2038-01-18T23:59:59+00:00
Days remaining
4136
Serial (hex)
01FD6D30FCA3CA51A81BBC640E35032D
Signature
RSA-SHA384
Public key
RSA 4096

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

E7:93:C9:B0:2F:D8:AA:13:E2:1C:31:22:8A:CC:B0:81:19:64:3B:74:9C:89:89:64:B1:74:6D:46:C3:D4:CB:D2
Certificate extensions & PEM
subjectKeyIdentifier
53:79:BF:5A:AA:2B:4A:CF:54:80:E1:D8:9B:C0:9D:F2:B2:03:66:CB
keyUsage
Certificate Sign, CRL Sign
basicConstraints
CA:TRUE
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

One endpoint on port 443. Server-presented chain; no revocation, OCSP, CT or full TLS security scan.

View certificate JSON

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