gradnadlanu.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:fc:a2:54:8f:c2:01:c0:d8:34:ef:a3:64:a8:f1:d1:7b:1d 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=gradnadlanu.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:fc:a2:54:8f:c2:01:c0:d8:34:ef:a3:64:a8:f1:d1:7b:1d
Serial Number (int): 347303788263365885499304311105084680403741
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 9d:e4:f1:54:09:a5:90:5c:ee:5e:bb:34:8e:e5:42:de:6d:6e:4a:87
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): dc:31:b9:ad:28:cd:3f:f4:39:3f:9d:6f:6a:bc:e0:ed:64:42:5b:cf
Fingerprint (sha256): b6:b3:e2:88:d3:89:a5:8c:2c:90:0e:b1:34:be:a6:0a:49:12:49:cc:9c:85:0b:86:9c:56:8f:f7:9d:7f:b5:a1

Issuing Certificate URL: http://cert.int-x3.letsencrypt.org/

Revocation information

OCSP Server: http://ocsp.int-x3.letsencrypt.org

Check the revocation status for certificate gradnadlanu.com

9

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for gradnadlanu.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.gradnadlanu.com
cpanel.gradnadlanu.com
gradnadlanu.com
gradnadlanu.redmarketing.hu
mail.gradnadlanu.com
webdisk.gradnadlanu.com
webmail.gradnadlanu.com
www.gradnadlanu.com
www.gradnadlanu.redmarketing.hu

Other certificates including the domain name gradnadlanu.com

(limited to 100 certificates)

Certificate

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

Certificate (PEM)

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

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAt+Vg+sAalU9O4WwUQZMS
8rttycHy6tRRkR+ukbnnknKWcPaPESObYaCPEc1jyPLNNo/zLvXx3WgSU4pJIMJ3
/ZhoPgyOQWR7KXrlo/KISu2xo9y6Eh+6rxcCZBemAPuJXMccr8JVBGnSvi9hWtoP
zoUZaIunnDAgcI6uARhy9f72A0OXH0pCMn4NehJ8FkG9MsHGJxlC71Jn+9xH66WW
EsMvJgq9H5gOJxGBKa1CooXn/PJCi2mFKNAR4I1s4wffbDveLHEr96lfE6GPU8Z1
gcA30jyEoXfATjviZ058QwH+T0OP+rGaiNPIfCZIUxoMUkbZvloVHQom115CQ9Ks
swIDAQAB
-----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 347303788263365885499304311105084680403741
 . . . . . . . . [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 2019-04-05 23:42:23 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-07-04 23:42:23 +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 'gradnadlanu.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 23214720723663612861299698684999533762219672916454712229310945672655185652853632987706815488475868283355532393797966063361336241746703209671417773580620674546422179592757426466993485922342012131657718064148206265055856011431023288757763700318403914777464372645377450828670403397246255201805507655165850667048450712666689334066480678629431813424399955208757993916331318212043993499861505621995816175802042967676348260554312072809827107983585793644871855202427156380785265368612619618422212655052807278711696504750565428283089176738009589799979349143095527051645478480226125898701343017600160093573509171421725393595571
 . . . . . . . . . . . . . . . . . . . . [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)
							9de4f15409a5905cee5ebb348ee542de6d6e4a87
 . . . . . . . . . . . . . . . . [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 (229 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'autodiscover.gradnadlanu.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'cpanel.gradnadlanu.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'gradnadlanu.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'gradnadlanu.redmarketing.hu'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'mail.gradnadlanu.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'webdisk.gradnadlanu.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'webmail.gradnadlanu.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.gradnadlanu.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.gradnadlanu.redmarketing.hu'
 . . . . . . . . . . . . . . . . [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 (244 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (241 bytes)
							00ef007600e2694bae26e8e94009e8861bb63b83d43ee7fe7488fba48f2893019dddf1dbfe00000169f018af0e0000040300473045022100c7091c75591ff549817f156f36a3e0465d24ad77dc3ac9dce90818570606fd970220784ceb0f61c3c41e309fba1ed934f28dbbc494c88ede78c0b1128bbf1a465eda007500293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f47800000169f018b17d00000403004630440220219eeb77e3a3560eb6587246a152da10c06d28fd883be3321d33672cafc8d1dc02200aa203cc899e92a009df658c623aea5bfa6e483d12d89582a0a230618e7effc0
 . . . . [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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