subhamcomputers.com
Issued by Let's Encrypt Authority X3
About this certificate
This digital certificate with serial number 03:85:6c:83:07:cf:22:91:fc:f7:8a:36:e4:76:e4:23:2f:68 was issued on by Let's Encrypt.
With 9 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=subhamcomputers.com
Let's Encrypt
Organization:
Let's Encrypt
Country:
US
This certificate has expire since
Certificate Details
Serial Number (hex): 03:85:6c:83:07:cf:22:91:fc:f7:8a:36:e4:76:e4:23:2f:68Serial Number (int): 306738649568586590402388309524796009557864
Serial Number lenght: 138 bits, 18 octets
SubjectKeyId: 2d:a5:9b:91:f9:cf:2c:a6:e0:aa:4f:0b:bb:51:87:7a:1a:e1:d5:9e
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1
Fingerprint (sha1): 40:f4:00:4a:98:ba:0b:c4:26:de:d9:98:e5:19:6e:6e:d9:76:d3:c1
Fingerprint (sha256): 1e:98:6f:dc:84:48:d7:ac:dc:6f:2f:23:78:3f:b0:68:2b:6c:8e:46:a1:f5:69:e7:6e:6d:3c:ce:b1:f1:11:13
Issuing Certificate URL: http://cert.int-x3.letsencrypt.org/
Revocation information
OCSP Server: http://ocsp.int-x3.letsencrypt.orgCheck the revocation status for certificate subhamcomputers.com
9
DNS Names
0
Email Addresses
0
IP Addresses
Advanced Certificate Properties
Tehnical certificate details for subhamcomputers.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
cpanel.subhamcomputers.com
mail.subhamcomputers.com
mail.subhamcomputers.com.cp-24.webhostbox.net
subhamcomputers.com
subhamcomputers.com.cp-24.webhostbox.net
webdisk.subhamcomputers.com
webmail.subhamcomputers.com
www.subhamcomputers.com
www.subhamcomputers.com.cp-24.webhostbox.net
mail.subhamcomputers.com
mail.subhamcomputers.com.cp-24.webhostbox.net
subhamcomputers.com
subhamcomputers.com.cp-24.webhostbox.net
webdisk.subhamcomputers.com
webmail.subhamcomputers.com
www.subhamcomputers.com
www.subhamcomputers.com.cp-24.webhostbox.net
Other certificates including the domain name subhamcomputers.com
(limited to 100 certificates)
Certificate
The complete raw certificate details for subhamcomputers.com in PEM and ASN.1 format.
Certificate (PEM)
-----BEGIN CERTIFICATE----- MIIGdTCCBV2gAwIBAgISA4VsgwfPIpH894o25HbkIy9oMA0GCSqGSIb3DQEBCwUA MEoxCzAJBgNVBAYTAlVTMRYwFAYDVQQKEw1MZXQncyBFbmNyeXB0MSMwIQYDVQQD ExpMZXQncyBFbmNyeXB0IEF1dGhvcml0eSBYMzAeFw0xOTAxMTkyMjQ3MTRaFw0x OTA0MTkyMjQ3MTRaMB4xHDAaBgNVBAMTE3N1YmhhbWNvbXB1dGVycy5jb20wggEi MA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDCj39+kNf/sGiu7pdjju52l2Tq jb/UAs6K4KaNCH5g1Nj9hKd4ubMyzs2sdjRPB9W7WAjyO1wGaIeR2dNQtQDrfq5B nV0m2d5TOQzuQMfwkEIHiQT4HlVJZ3aeopXQl2h/gXYWu58WOKaspHbtHlWEyukZ NCZWVSoJGsqsrxBURto9KEv3YYDlvXuHjako/f+dQMR5EIWpp/ZV+cd8Xv9k+ywB 9BtqX/SFnMmmPPi+z/xcqDGm/cgNFKtwQNukDk2k1rAZP4bCDi5VFlkIL0Q/Wj9n mQoDXCKABAotbOQMma4gf6yMCk3Yu1w5bjQB+NBpSLcb160LkGo71cf7lIePAgMB AAGjggN/MIIDezAOBgNVHQ8BAf8EBAMCBaAwHQYDVR0lBBYwFAYIKwYBBQUHAwEG CCsGAQUFBwMCMAwGA1UdEwEB/wQCMAAwHQYDVR0OBBYEFC2lm5H5zyym4KpPC7tR h3oa4dWeMB8GA1UdIwQYMBaAFKhKamMEfd265tE5t6ZFZe/zqOyhMG8GCCsGAQUF BwEBBGMwYTAuBggrBgEFBQcwAYYiaHR0cDovL29jc3AuaW50LXgzLmxldHNlbmNy eXB0Lm9yZzAvBggrBgEFBQcwAoYjaHR0cDovL2NlcnQuaW50LXgzLmxldHNlbmNy eXB0Lm9yZy8wggEyBgNVHREEggEpMIIBJYIaY3BhbmVsLnN1YmhhbWNvbXB1dGVy cy5jb22CGG1haWwuc3ViaGFtY29tcHV0ZXJzLmNvbYItbWFpbC5zdWJoYW1jb21w dXRlcnMuY29tLmNwLTI0LndlYmhvc3Rib3gubmV0ghNzdWJoYW1jb21wdXRlcnMu Y29tgihzdWJoYW1jb21wdXRlcnMuY29tLmNwLTI0LndlYmhvc3Rib3gubmV0ght3 ZWJkaXNrLnN1YmhhbWNvbXB1dGVycy5jb22CG3dlYm1haWwuc3ViaGFtY29tcHV0 ZXJzLmNvbYIXd3d3LnN1YmhhbWNvbXB1dGVycy5jb22CLHd3dy5zdWJoYW1jb21w dXRlcnMuY29tLmNwLTI0LndlYmhvc3Rib3gubmV0MEwGA1UdIARFMEMwCAYGZ4EM AQIBMDcGCysGAQQBgt8TAQEBMCgwJgYIKwYBBQUHAgEWGmh0dHA6Ly9jcHMubGV0 c2VuY3J5cHQub3JnMIIBBQYKKwYBBAHWeQIEAgSB9gSB8wDxAHcAdH7agzGtMxCR IZzOJU9CcMK//V5CIAjGNzV55hB7zFYAAAFoaILgjgAABAMASDBGAiEAhfcVd72r NKd3FuFWqNI2yRics2htu4cKP1TFakULIiQCIQCDxRVUGeRUrniVYHdtpCMqSKft Yut1EmkZGix0AnkA0QB2ACk8UZZUyDlluqpQ/FgH1Ldvv1h6KXLcpMMM9OVFR/R4 AAABaGiC4PQAAAQDAEcwRQIhAM7AQEGyj8MAV9KDRef3Uoy5oXD4R+9BrMUngFUh Edy8AiB/cQIV9sh8An2dKwqhRfuAgJBJ0eHHhOOwG3Ju4uXNXDANBgkqhkiG9w0B AQsFAAOCAQEAXNz+w3b9+g48DrrsCsS9Lt0x0C1u74K1NOSYHY/WjMVT9b/iWTp0 UUISG+7qjzBZANHv5nUyz9FABoZCLI0tI+SrsktQqUXSeBKqlg5n9pCue19JhDXv nAP9dnMG7tii08XmTGS8GXlbpfqYRrrPUfGk6arFtFxzJR1dsY1sSbKwUo5HiGt9 YsQE68vK9dhBIjMdOTZ2pJ0lgjTfFxTcC7EeIiXerLa7zHYGaSs0CL67if5ESnZk RgbNhtdHXJgvggjbIlb5CMcOvgBxWLkeF6wHhz1JzwZQ527NFS5Bz3f/rBvB1cI5 MmgYS+XJK1seQUREtotZm7ZHseILE3dSwQ== -----END CERTIFICATE-----
Public Key (PEM)
-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAwo9/fpDX/7Boru6XY47u dpdk6o2/1ALOiuCmjQh+YNTY/YSneLmzMs7NrHY0TwfVu1gI8jtcBmiHkdnTULUA 636uQZ1dJtneUzkM7kDH8JBCB4kE+B5VSWd2nqKV0Jdof4F2FrufFjimrKR27R5V hMrpGTQmVlUqCRrKrK8QVEbaPShL92GA5b17h42pKP3/nUDEeRCFqaf2VfnHfF7/ ZPssAfQbal/0hZzJpjz4vs/8XKgxpv3IDRSrcEDbpA5NpNawGT+Gwg4uVRZZCC9E P1o/Z5kKA1wigAQKLWzkDJmuIH+sjApN2LtcOW40AfjQaUi3G9etC5BqO9XH+5SH jwIDAQAB -----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 306738649568586590402388309524796009557864 . . . . . . . . [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 2.5.4.10 (organizationName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Let's Encrypt' . . . . . . . . . . . . [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 'Let's Encrypt Authority X3' . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-01-19 22:47:14 +0000 UTC . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-04-19 22:47:14 +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 'subhamcomputers.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 24560992676856050149076932909174300445266404820817017630130878091572273794933593536927994516132509991828426865379294172751969211463421140558069818881952912357203306313092448681003069417723702399968606376350482841426600487787272279655491943816010607073193522992151665134314275934708170580904168794231059755584312026722453418181181930169891223244342190118198283768594898210608098949533424985661433424613342394525224070617725623278226937041663796687052239702079759097820755723949652922269105273729448682044975231700372919779019355436588269555387545041802091016536677700939468518535368089044202524667010082043937569408911 . . . . . . . . . . . . . . . . . . . . [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 2.5.29.15 (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 2.5.29.37 (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 2.5.29.19 (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 2.5.29.14 (subjectKeyIdentifier) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (22 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (20 bytes) 2da59b91f9cf2ca6e0aa4f0bbb51877a1ae1d59e . . . . . . . . . . . . . . . . [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 a84a6a63047dddbae6d139b7a64565eff3a8eca1 . . . . . . . . . . . . . . . . [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 (99 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.48.1 (ocsp) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:6|false] IA5String 'http://ocsp.int-x3.letsencrypt.org' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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://cert.int-x3.letsencrypt.org/' . . . . . . . . . . . . . . . . [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 (297 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'cpanel.subhamcomputers.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'mail.subhamcomputers.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'mail.subhamcomputers.com.cp-24.webhostbox.net' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'subhamcomputers.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'subhamcomputers.com.cp-24.webhostbox.net' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'webdisk.subhamcomputers.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'webmail.subhamcomputers.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.subhamcomputers.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.subhamcomputers.com.cp-24.webhostbox.net' . . . . . . . . . . . . . . . . [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 (69 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.23.140.1.2.1 (Domain Validation Certificates Policy) . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.4.1.44947.1.1.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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 'http://cps.letsencrypt.org' . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.4.1.11129.2.4.2 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (246 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (243 bytes) 00f1007700747eda8331ad331091219cce254f4270c2bffd5e422008c6373579e6107bcc56000001686882e08e000004030048304602210085f71577bdab34a77716e156a8d236c9189cb3686dbb870a3f54c56a450b222402210083c5155419e454ae789560776da4232a48a7ed62eb751269191a2c74027900d1007600293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f478000001686882e0f40000040300473045022100cec04041b28fc30057d28345e7f7528cb9a170f847ef41acc52780552111dcbc02207f710215f6c87c027d9d2b0aa145fb80809049d1e1c784e3b01b726ee2e5cd5c . . . . [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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