www.79283.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:90:e9:c6:c8:c8:1e:aa:be:97:5d:2c:35:1f:7e:80:c7:85 was issued on by Let's Encrypt.

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=www.79283.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:90:e9:c6:c8:c8:1e:aa:be:97:5d:2c:35:1f:7e:80:c7:85
Serial Number (int): 310648260902028798173767409108188223555461
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 96:2f:b3:63:64:46:c2:52:2e:1c:3f:ae:0d:bc:dd:e9:9b:6d:99:a2
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): f5:7d:d6:d0:c3:79:ec:ff:9a:cf:7f:54:c3:1b:5c:26:68:ba:0a:3f
Fingerprint (sha256): f4:a1:6e:a5:24:70:1f:e9:c3:7c:73:ce:14:61:2e:38:47:8f:91:de:8f:41:29:fd:2f:e3:22:f9:11:07:09:e5

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 www.79283.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for www.79283.com

Public Key Algorithm

RSA

Key Size

4096

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

www.79283.com

Other certificates including the domain name 79283.com

(limited to 100 certificates)
79283.com
79283.com
91852.com
michela.org
79283.com
www.79283.com
71882.com
www.79283.com
79283.com
79283.com
www.79283.com
www.79283.com
79283.com
79283.com
www.79283.com
www.79283.com
79283.com

Certificate

The complete raw certificate details for www.79283.com in PEM and ASN.1 format.

Certificate (PEM)

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

Public Key (PEM)

-----BEGIN PUBLIC KEY-----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-----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 310648260902028798173767409108188223555461
 . . . . . . . . [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 2019-10-23 09:04:48 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-01-21 09:04:48 +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 'www.79283.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 (4208 bits)
 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . [c:0|t:2|false] INTEGER 733709923503077667987388697210988391256752595998851987041801440763124179820863903123914269429342175463292613707357160407522104442548105761985742915642078539513967020557714744859579481781009753069788313691533772498238577676953477396604574809554061940348567414724887822470556013769383387370478994866697927452411478151938946442646605873379191976054521011503482423902817701786526552592395151394373764943794342746174179458440231323756637273882282205309878507912143408194987615632172677727256319056329897292329071690370583664532869001249479144014405288384379366126898645981495803001509403829883765278316630411466529045360695071906170528908554057186252381978452290432350733310378291751059699106433846847499287049075245796727885416473926540386216268149382116725345209653356783928857474830167266133583251520644562715962883153373025650229928850074410944073512873686882453330024260593366330523182959341697444797091426403392180456213837554253288643796141808660244209354773002910536555117901575489430163011514894486876336569852866193626851553775820569101436117003239085301886205475218323508770090179628411944994419331848833012676434323554969213792600244314651634158543680339698758870239984106076404909510550036589069868506558785150437456677340091
 . . . . . . . . . . . . . . . . . . . . [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)
							962fb3636446c2522e1c3fae0dbcdde99b6d99a2
 . . . . . . . . . . . . . . . . [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 (17 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.79283.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 (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)
							00ef0075005ea773f9df56c0e7b536487dd049e0327a919a0c84a1121284187596817145580000016df8137753000004030046304402200107367131f3747a75098c9200f31a0cf21634cf39b5fa5dc20475039f0619ab022002907d313513ae4e57c4db2e77b6f5b05bf2c122403c4c400c9969a15240e355007600b21e05cc8ba2cd8a204e8766f92bb98a2520676bdafa70e7b249532def8b905e0000016df81377490000040300473045022100f3fc8e8c762ba3e9fa2b697337b35033cd9f29138ea0ad7fe8f60f8fc45d02a10220606678c1eec322fd8a7725629926e7f3a3e6286abeae3ca6932f427cfd2f5c5c
 . . . . [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)
		0038c4794ffdc1083973bfaac89033e25bce7cc425d166e4af5af20ce37cab14487e46186bc9d839a5368092f6ae290ca8ac992e628c63e9623362ccbe7d8f66bc2ed92a4e159ad07c6fb4d6e48645c96878c765a4d2e6293bd394a13f1c9cf029b28cf07f9bd3df9074e36b8df082630d3c51fb83299d68046f114571aebe877af73868a02a48231fbc9b99019f22e2852f74b13a56f62a335e3713d718a3882f613c364599012a2664a68ba8f1b0da4cbf6f459c528c79bc996facef4f3a3558f4784e0e47936614db59f8bec33409a951d1ce2a9f1a7a839375fd837c82a8b6546d7fd085c42685ffba47201acfeed5720228b2766fff10b89319c5a17827ab