mail.vinniescarkey.com

Issued by R3

About this certificate

This digital certificate with serial number 04:19:a6:3b:a4:8e:7e:d0:a4:84:c6:1a:f6:cb:c1:2c:a8:48 was issued on by Let's Encrypt.

With 12 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:
  • DV certificate contains a subject common name, this is not recommended. If certificate policy 2.23.140.1.2.1 (CA/B BR domain validated) is included, only country and/or common name is allowed in SubjectDN. (BRs: 7.1.2.7.2)
  • Subscriber certificates use of Subject Key Identifier is NOT RECOMMENDED (BRs v2: 7.1.2.7.6)
  • Subscriber Certificate: commonName is NOT RECOMMENDED. (BRs: 7.1.2.7.1)

Certificate Subject

CN=mail.vinniescarkey.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 04:19:a6:3b:a4:8e:7e:d0:a4:84:c6:1a:f6:cb:c1:2c:a8:48
Serial Number (int): 357177164430484219183436881656050287945800
Serial Number lenght: 139 bits, 18 octets

SubjectKeyId: 81:be:62:0b:25:2c:79:f1:40:62:1e:49:82:5a:5b:19:47:ae:bb:5c
AuthorityKeyId: 14:2e:b3:17:b7:58:56:cb:ae:50:09:40:e6:1f:af:9d:8b:14:c2:c6

Fingerprint (sha1): bd:16:7d:f5:52:a3:52:32:f5:d4:9c:fd:49:67:56:c0:bb:36:c0:b0
Fingerprint (sha256): 00:f4:9d:13:51:56:e6:37:8d:5f:d0:a6:00:fa:1a:a3:d0:23:40:50:9b:6c:dd:7f:db:43:05:ad:f1:1a:ef:3d

Issuing Certificate URL: http://r3.i.lencr.org/

Revocation information

OCSP Server: http://r3.o.lencr.org

Check the revocation status for certificate mail.vinniescarkey.com

12

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for mail.vinniescarkey.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

autodiscover.pai.xxa.temporary.site
cpanel.pai.xxa.temporary.site
cpcalendars.pai.xxa.temporary.site
cpcontacts.pai.xxa.temporary.site
mail.pai.xxa.temporary.site
mail.vinniescarkey.com
pai.xxa.temporary.site
vinniescarkey.com
webdisk.pai.xxa.temporary.site
webmail.pai.xxa.temporary.site
www.pai.xxa.temporary.site
www.vinniescarkey.com

Other certificates including the domain name vinniescarkey.com

(limited to 100 certificates)
mail.vinniescarkey.com

Certificate

The complete raw certificate details for mail.vinniescarkey.com in PEM and ASN.1 format.

Certificate (PEM)

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAzVvV7UlDmftn/KAkWUBf
nNCoJEdBr294RRPBPXz6GLiN7mKXMO9GPshMydL7LwCB+vNq9ogUwUGJQsirivM2
9srEyE0ewFQdc9S7TdXCElrw9Qs8188IAUejU6cf3YIPue5fMZq/cSvpIMKG6NDo
39yeqcWk+sUMoW+usd+HMinb3yd4kmCv/iY51G63tyBNZeEsrkHt6SvS3szlxMSP
bXallGj0TjdnnYf3VjK+ut/3RsaT84Mmny/14T6XvLhuYXmaSiaVEbRjR7HjS3Lf
5aHqJH5jBOwbHVajBIMDvbBru5Pk4qSbVXn+Jly1uKAO4KLjJiELFxriqgQzZT7d
JQIDAQAB
-----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 357177164430484219183436881656050287945800
 . . . . . . . . [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 'R3'
 . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2024-03-12 18:00:09 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2024-06-10 18:00:08 +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 'mail.vinniescarkey.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 25924138365845168339482598790411156141798633431908772994362426801913256972214910081114067586411889142451481413959811048259743500366203221058001670016308874111943010021423636332132893780868621284909584810449963771099918446274769126812873243327205872194490171008505892963288736509127145248051335819421511005156416008998753301287998422699967567169997009521364373868341306246942256260614057582967659565132818252361150798890756266374343845756889706127357772428797700066808236889097684039326225722600639159790316024574695470572565598335476989283883553865534494251192824290075706115183454482559329100002922423416773859532069
 . . . . . . . . . . . . . . . . . . . . [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)
							81be620b252c79f140621e49825a5b1947aebb5c
 . . . . . . . . . . . . . . . . [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 142eb317b75856cbae500940e61faf9d8b14c2c6
 . . . . . . . . . . . . . . . . [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 (73 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://r3.o.lencr.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://r3.i.lencr.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 (354 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'autodiscover.pai.xxa.temporary.site'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'cpanel.pai.xxa.temporary.site'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'cpcalendars.pai.xxa.temporary.site'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'cpcontacts.pai.xxa.temporary.site'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'mail.pai.xxa.temporary.site'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'mail.vinniescarkey.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'pai.xxa.temporary.site'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'vinniescarkey.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'webdisk.pai.xxa.temporary.site'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'webmail.pai.xxa.temporary.site'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.pai.xxa.temporary.site'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.vinniescarkey.com'
 . . . . . . . . . . . . . . . . [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 (12 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 1.3.6.1.4.1.11129.2.4.2
 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (245 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (242 bytes)
							00f00077003b5377753e2db9804e8b305b06fe403b67d84fc3f4c7bd000d2d726fe1fad4170000018e340953340000040300483046022100910958a25052fd2d98e3bff439d0e424110875c807076d9d6c99c29b5a1ecaf602210090294edb550b3e54a1062249cb2fdfde5bb65d8740f365d4a68880cbe3da0b73007500eecdd064d5db1acec55cb79db4cd13a23287467cbcecdec351485946711fb59b0000018e3409532a00000403004630440220780f8eeb917dc9b91be5605ea1020ee83a025bea93a1170fbb7fe38b26df59db02205c0f5184596aca498970e9a4e2c9800a4328ff662413cad4990ad234b1dc5d1c
 . . . . [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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