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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

proton.ch · 185.70.42.21:443

Verified

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

Subject
CN=proton.ch
Issuer
C=US O=Let's Encrypt CN=YR1
Valid from
2026-09-06T13:13:30+00:00
Expires
2026-12-05T13:13:29+00:00
Days remaining
70
Serial (hex)
0696257AF6149C355ED3A08FEA248DD0BBB8
Signature
RSA-SHA256
Public key
RSA 4096

Subject alternative names (SAN)

DNS:*.proton.ch, DNS:proton.ch

SHA-256 fingerprint

F4:F9:02:CD:52:02:3D:0A:9E:61:AE:4C:34:E7:69:BC:C7:E7:DE:45:FA:EE:1F:A8:56:0F:52:68:3C:9B:00:AA
Certificate extensions & PEM
keyUsage
Digital Signature, Key Encipherment
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:FALSE
subjectKeyIdentifier
B8:6C:83:5B:4A:D3:08:DB:90:2A:CD:FE:99:01:EB:E3:CD:D0:47:56
authorityKeyIdentifier
1F:2F:35:BE:46:14:82:CD:40:B1:AE:79:2C:55:78:FA:F7:D4:68:FB
authorityInfoAccess
CA Issuers - URI:http://yr1.i.lencr.org/
subjectAltName
DNS:*.proton.ch, DNS:proton.ch
certificatePolicies
Policy: 2.23.140.1.2.1
crlDistributionPoints
Full Name: URI:http://yr1.c.lencr.org/57.crl
ct_precert_scts
Signed Certificate Timestamp: Version : v1 (0x0) Log ID : D7:6D:7D:10:D1:A7:F5:77:C2:C7:E9:5F:D7:00:BF:F9: 82:C9:33:5A:65:E1:D0:B3:01:73:17:C0:C8:C5:69:77 Timestamp : Sep 6 14:12:00.295 2026 GMT Extensions: none Signature : ecdsa-with-SHA256 30:45:02:20:62:2C:95:35:C6:24:1D:66:49:8C:81:92: 65:45:20:55:34:10:E8:DC:2F:3D:F3:67:18:0B:4C:07: B8:20:85:62:02:21:00:BC:35:1B:99:B7:B7:9D:5E:0C: 8D:E7:D7:C1:05:CC:54:BE:3F:B2:8C:E0:62:41:9C:4E: 20:AC:C6:92:30:4A:59 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 6 14:12:00.552 2026 GMT Extensions: 00:00:05:00:26:6F:D6:62 Signature : ecdsa-with-SHA256 30:45:02:21:00:8A:DC:83:58:67:E3:74:7E:35:C7:60: D9:E1:6D:30:A9:26:E3:68:36:A0:7C:7B:E9:15:3A:16: 6A:15:AF:76:9D:02:20:02:15:F5:6E:01:34:F4:36:5A: 06:A1:67:DC:8F:05:76:5C:E9:56:99:71:78:B5:E1:F9: 25:95:25:F4:AA:A8:0C
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Cipher: TLS_AES_128_GCM_SHA256 · Checked 2026-09-25T22:44:26+00:00

Server-presented chain · 2 additional certificates

Chain certificate 1

Subject
C=US O=Let's Encrypt CN=YR1
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
708
Serial (hex)
A20253F15F2691C05DC1CE13B9BCCA4E
Signature
RSA-SHA256
Public key
RSA 2048

Subject alternative names (SAN)

No SAN extension was presented.

SHA-256 fingerprint

13:94:96:34:D9:9C:D6:FD:6A:A8:0B:C0:34:FE:FA:CC:EB:19:69:FE:EF:98:65:86:71:3E:CD:BB:05:75:8D:3F
Certificate extensions & PEM
keyUsage
Digital Signature, Certificate Sign, CRL Sign
extendedKeyUsage
TLS Web Server Authentication
basicConstraints
CA:TRUE, pathlen:0
subjectKeyIdentifier
1F:2F:35:BE:46:14:82:CD:40:B1:AE:79:2C:55:78:FA:F7:D4:68:FB
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
2169
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

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