chronic-kidney-disease.com
Issued by Let's Encrypt Authority X3
About this certificate
This digital certificate with serial number 03:38:7e:ff:fb:52:6f:fe:42:34:e7:a6:97:f1:b1:66:64:de was issued on by Let's Encrypt.
With 7 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=chronic-kidney-disease.com
Let's Encrypt
Organization:
Let's Encrypt
Country:
US
This certificate has expire since
Certificate Details
Serial Number (hex): 03:38:7e:ff:fb:52:6f:fe:42:34:e7:a6:97:f1:b1:66:64:deSerial Number (int): 280561482203437299733491245759168478864606
Serial Number lenght: 138 bits, 18 octets
SubjectKeyId: 00:07:71:5f:44:d3:55:1d:d0:34:f4:18:1c:72:99:17:e8:78:72:05
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1
Fingerprint (sha1): 61:d0:ed:5c:4d:4f:e6:2d:a8:9c:16:4d:47:57:23:65:8a:29:05:2b
Fingerprint (sha256): 29:c0:e1:a7:6f:5f:9b:0d:97:6f:56:8b:db:e7:5e:e2:7a:40:29:71:4c:24:77:17:6f:59:2e:f6:1b:16:a7:a4
Issuing Certificate URL: http://cert.int-x3.letsencrypt.org/
Revocation information
OCSP Server: http://ocsp.int-x3.letsencrypt.orgCheck the revocation status for certificate chronic-kidney-disease.com
7
DNS Names
0
Email Addresses
0
IP Addresses
Advanced Certificate Properties
Tehnical certificate details for chronic-kidney-disease.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
chronic-kidney-disease.com
ckd.news
diet-in-chronic-kidney-disease.com
ketosteril.i-tribe.de
www.chronic-kidney-disease.com
www.ckd.news
www.ketosteril.i-tribe.de
ckd.news
diet-in-chronic-kidney-disease.com
ketosteril.i-tribe.de
www.chronic-kidney-disease.com
www.ckd.news
www.ketosteril.i-tribe.de
Other certificates including the domain name chronic-kidney-disease.com
(limited to 100 certificates)
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
bmi-bot.chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
bmi-bot.chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
bmi-bot.chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
chronic-kidney-disease.com
bmi-bot.chronic-kidney-disease.com
chronic-kidney-disease.com
Certificate
The complete raw certificate details for chronic-kidney-disease.com in PEM and ASN.1 format.
Certificate (PEM)
-----BEGIN CERTIFICATE----- MIIF/TCCBOWgAwIBAgISAzh+//tSb/5CNOeml/GxZmTeMA0GCSqGSIb3DQEBCwUA MEoxCzAJBgNVBAYTAlVTMRYwFAYDVQQKEw1MZXQncyBFbmNyeXB0MSMwIQYDVQQD ExpMZXQncyBFbmNyeXB0IEF1dGhvcml0eSBYMzAeFw0xOTAzMTMxMTQ0MjVaFw0x OTA2MTExMTQ0MjVaMCUxIzAhBgNVBAMTGmNocm9uaWMta2lkbmV5LWRpc2Vhc2Uu Y29tMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAwdpQAfRDIL/qnRfB f4WmtrZWJES13CAVw1DncLKYX0cM0L99Suz8UFXc474np5hCR42kPkiKeHLfyiF+ zSZjVe77c+5hH7nW213CFfY5sAMV11kuDBRJe/e2DtBv+0doHblxQdYGzp6zNTQd TK2OadK5fHYK6JzFQjRpNPyLL8SseVSGDsmFvUL49a/ckMNTYH3YshP4rT09bILI Awx2/OhnHqlfQZp2FAQ22FYDkZFRtuSHJCrOsl89e19GnusMLJNiVeuLW4/plGHI Pg12EyQjfcFXQA3EQVnSrAWvBdbPjkNk4VgV9f+Yu1wIUrPi71l2aLJ/EBmeNgAz qL1bNQIDAQABo4IDADCCAvwwDgYDVR0PAQH/BAQDAgWgMB0GA1UdJQQWMBQGCCsG AQUFBwMBBggrBgEFBQcDAjAMBgNVHRMBAf8EAjAAMB0GA1UdDgQWBBQAB3FfRNNV HdA09BgccpkX6HhyBTAfBgNVHSMEGDAWgBSoSmpjBH3duubRObemRWXv86jsoTBv BggrBgEFBQcBAQRjMGEwLgYIKwYBBQUHMAGGImh0dHA6Ly9vY3NwLmludC14My5s ZXRzZW5jcnlwdC5vcmcwLwYIKwYBBQUHMAKGI2h0dHA6Ly9jZXJ0LmludC14My5s ZXRzZW5jcnlwdC5vcmcvMIG1BgNVHREEga0wgaqCGmNocm9uaWMta2lkbmV5LWRp c2Vhc2UuY29tgghja2QubmV3c4IiZGlldC1pbi1jaHJvbmljLWtpZG5leS1kaXNl YXNlLmNvbYIVa2V0b3N0ZXJpbC5pLXRyaWJlLmRlgh53d3cuY2hyb25pYy1raWRu ZXktZGlzZWFzZS5jb22CDHd3dy5ja2QubmV3c4IZd3d3LmtldG9zdGVyaWwuaS10 cmliZS5kZTBMBgNVHSAERTBDMAgGBmeBDAECATA3BgsrBgEEAYLfEwEBATAoMCYG CCsGAQUFBwIBFhpodHRwOi8vY3BzLmxldHNlbmNyeXB0Lm9yZzCCAQQGCisGAQQB 1nkCBAIEgfUEgfIA8AB3AHR+2oMxrTMQkSGcziVPQnDCv/1eQiAIxjc1eeYQe8xW AAABaXcVGYgAAAQDAEgwRgIhALZsiWgEtnAwxAcwAXtqZ1UYgSDZe03HkconUl2A vFLfAiEAntzNBrgZD5pyAjUKInkfPuJEddJSV+cVRdlAEBLyjqsAdQBj8tvN6DvM LM8LcoQnV2szpI1hd4+9daY4scdoVEvYjQAAAWl3FRleAAAEAwBGMEQCIEAwm7L5 TcqFz/YcD3BsUrgR8eC2TmPkwpmUTGA6i9C8AiATbNr5UHS8ttSCkrYIlIgc+ZHp L1CnLDB4gutEuVWIgDANBgkqhkiG9w0BAQsFAAOCAQEAYDfqHnNhwZZLt0KDEkoT S7hXG4LDpyYsja1H7/6JKOh1hFw6JRtMI5/Mj5INNePB+RjIe1yF6+UP9LOzoHLn buKkDWntDtaemQNja83XFmt5eQro7riZGsmuTRXaWIMAiQ2nRnR5sj8r20lFvKQo XXllFaKhvDxIvB+zbMX65Oqj6agpdBBafqYsmyelHwH3FsAk0falYexng2OoEpzK uPN1yvA+RKPRZp0y7l9ljHSl4PxFpCy6vMa2ZARgjk+zF8IpzPd6CpzSqsYZpoai 8J8t667REVCLqoPjRKWCJqDi5BmifoqV8hD0SKIRlJ7mJ0VTHo5k73HIB3mUEUQp HA== -----END CERTIFICATE-----
Public Key (PEM)
-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAwdpQAfRDIL/qnRfBf4Wm trZWJES13CAVw1DncLKYX0cM0L99Suz8UFXc474np5hCR42kPkiKeHLfyiF+zSZj Ve77c+5hH7nW213CFfY5sAMV11kuDBRJe/e2DtBv+0doHblxQdYGzp6zNTQdTK2O adK5fHYK6JzFQjRpNPyLL8SseVSGDsmFvUL49a/ckMNTYH3YshP4rT09bILIAwx2 /OhnHqlfQZp2FAQ22FYDkZFRtuSHJCrOsl89e19GnusMLJNiVeuLW4/plGHIPg12 EyQjfcFXQA3EQVnSrAWvBdbPjkNk4VgV9f+Yu1wIUrPi71l2aLJ/EBmeNgAzqL1b NQIDAQAB -----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 280561482203437299733491245759168478864606 . . . . . . . . [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 2019-03-13 11:44:25 +0000 UTC . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-06-11 11:44:25 +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 'chronic-kidney-disease.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 24471646779219120227131706272339106286999104336517068213683885190338766955498907888974902152877993513795397177886454142653516264980133089142255154544208756867354262266739674093736673059233390613111234613628844207920764322241339485736283519860538983931660755692456030747396779284641716804016228540265421383652420732685672986719369842235633446795474964734605729098016024403603552123629911491811731710975097219229140188312894345528459933577228988040505190414353796683936341234585716188607572297679262568040713365224367756577078901946730034914821274209422422165025570838028834916920580718335694691225392080149821007944501 . . . . . . . . . . . . . . . . . . . . [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) 0007715f44d3551dd034f4181c729917e8787205 . . . . . . . . . . . . . . . . [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 (173 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'chronic-kidney-disease.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'ckd.news' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'diet-in-chronic-kidney-disease.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'ketosteril.i-tribe.de' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.chronic-kidney-disease.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.ckd.news' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.ketosteril.i-tribe.de' . . . . . . . . . . . . . . . . [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 (245 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (242 bytes) 00f0007700747eda8331ad331091219cce254f4270c2bffd5e422008c6373579e6107bcc5600000169771519880000040300483046022100b66c896804b67030c40730017b6a6755188120d97b4dc791ca27525d80bc52df0221009edccd06b8190f9a7202350a22791f3ee24475d25257e71545d9401012f28eab00750063f2dbcde83bcc2ccf0b728427576b33a48d61778fbd75a638b1c768544bd88d000001697715195e0000040300463044022040309bb2f94dca85cff61c0f706c52b811f1e0b64e63e4c299944c603a8bd0bc0220136cdaf95074bcb6d48292b60894881cf991e92f50a72c307882eb44b9558880 . . . . [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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