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

jcu.cz · 160.217.6.39:443

Verified

Certificate chain, hostname and dates verified using this server’s CA store.

Subject
CN=jcu.cz
Issuer
C=US O=Let's Encrypt CN=YR2
Valid from
2026-09-20T03:48:56+00:00
Expires
2026-12-19T03:48:55+00:00
Days remaining
42
Serial (hex)
054BCED6B886FFACF8753D722A2999D5CFC6
Signature
RSA-SHA256
Public key
RSA 4096

Subject alternative names (SAN)

DNS:jcu.cz, DNS:sds.jcu.cz, DNS:www.jcu.cz

SHA-256 fingerprint

FC:71:42:A4:57:3C:90:A5:C8:26:56:B7:7B:88:7E:D9:4B:7B:65:E0:0B:FF:C6:FC:E3:88:9B:EB:7B:60:A0:75
Certificate extensions & PEM
keyUsage
Digital Signature, Key Encipherment
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:FALSE
subjectKeyIdentifier
BD:08:DC:C8:41:7A:43:27:25:22:64:E9:E0:59:14:9F:CC:46:01:01
authorityKeyIdentifier
40:15:2D:26:79:ED:32:20:9E:DF:9A:72:1D:D6:32:1F:81:0C:81:0C
authorityInfoAccess
CA Issuers - URI:http://yr2.i.lencr.org/
subjectAltName
DNS:jcu.cz, DNS:sds.jcu.cz, DNS:www.jcu.cz
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://yr2.c.lencr.org/71.crl
ct_precert_scts
Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 94:4E:43:87:FA:EC:C1:EF:81:F3:19:24:26:A8:18:65: 01:C7:D3:5F:38:02:01:3F:72:67:7D:55:37:2E:19:D8 Timestamp : Sep 20 04:47:26.584 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:45:02:21:00:88:D1:B2:FE:A4:EF:D8:35:D1:17:B0: D7:29:A4:E6:B2:E4:C7:38:F2:2E:BC:97:33:4B:6F:DB: EF:36:9A:36:AE:02:20:66:2A:A7:8A:88:BA:2A:B9:6A: 44:1B:18:1C:E9:ED:C0:AD:CA:A3:35:3A:87:CF:F5:9E: 23:F6:AE:B4:72:A5:C5 Signed Certificate Timestamp: Version : v1 (0x0) Log ID : 46:AF:86:3D:3B:3E:E5:9F:A5:77:DE:A8:24:5D:36:B0: D9:ED:22:A2:23:F4:61:77:41:22:94:52:EE:95:50:5F Timestamp : Sep 20 04:47:26.735 2026 GMT Extensions: 00:00:05:00:32:55:A8:5F Signature : ecdsa-with-SHA256 30:44:02:20:3D:B4:92:94:7D:5D:C1:F1:DE:03:80:2C: 49:61:73:17:DB:8D:0A:3D:F8:88:02:66:D9:F0:13:B8: 2C:6B:36:2B:02:20:71:9C:59:13:CF:DC:84:50:3A:9D: C0:63:9D:6B:7B:1C:02:A6:6F:3D:56:08:94:D2:8E:D0: 22:2B:DD:B2:5C:19
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Cipher: TLS_AES_128_GCM_SHA256 · Checked 2026-11-06T15:00:17+00:00

Server-presented chain · 2 additional certificates

Chain certificate 1

Subject
C=US O=Let's Encrypt CN=YR2
Issuer
C=US O=ISRG CN=Root YR
Valid from
2025-09-03T00:00:00+00:00
Expires
2028-09-02T23:59:59+00:00
Days remaining
666
Serial (hex)
4EBD24947E24D394802D84A52FD5B319
Signature
RSA-SHA256
Public key
RSA 2048

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

23:8B:85:A0:09:9C:65:B9:70:47:7D:57:24:F1:A1:D4:75:CE:50:58:CF:FE:4E:FA:87:33:89:9B:DB:86:3C:47
Certificate extensions & PEM
keyUsage
Digital Signature, Certificate Sign, CRL Sign
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:TRUE, pathlen:0
subjectKeyIdentifier
40:15:2D:26:79:ED:32:20:9E:DF:9A:72:1D:D6:32:1F:81:0C:81:0C
authorityKeyIdentifier
DE:E7:5B:60:D0:22:6D:40:28:7D:3F:0D:01:FE:A4:B5:52:B4:51:94
authorityInfoAccess
CA Issuers - URI:http://yr.i.lencr.org/
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://yr.c.lencr.org/ 
-----BEGIN CERTIFICATE-----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==
-----END CERTIFICATE-----

Chain certificate 2

Subject
C=US O=ISRG CN=Root YR
Issuer
C=US O=Internet Security Research Group CN=ISRG Root X1
Valid from
2026-05-13T00:00:00+00:00
Expires
2032-09-02T23:59:59+00:00
Days remaining
2127
Serial (hex)
F24B6D17F9D9AD7CB1C9FEA78782699F
Signature
RSA-SHA256
Public key
RSA 4096

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

07:26:39:D0:B1:40:D5:BF:FA:E1:6A:D9:C3:F6:CC:60:86:04:06:21:F5:1E:E6:1A:6D:46:A8:91:5C:07:CF:76
Certificate extensions & PEM
keyUsage
Certificate Sign, CRL Sign
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:TRUE
subjectKeyIdentifier
DE:E7:5B:60:D0:22:6D:40:28:7D:3F:0D:01:FE:A4:B5:52:B4:51:94
authorityKeyIdentifier
79:B4:59:E6:7B:B6:E5:E4:01:73:80:08:88:C8:1A:58:F6:E9:9B:6E
authorityInfoAccess
CA Issuers - URI:http://x1.i.lencr.org/
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://x1.c.lencr.org/ 
-----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

Registration / WHOIS →DNS records →