www.584.me

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:b3:ee:96:1d:6f:cb:45:20:c8:56:92:cc:d7:e9:a4:c0:05 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.584.me

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:b3:ee:96:1d:6f:cb:45:20:c8:56:92:cc:d7:e9:a4:c0:05
Serial Number (int): 322564537178701428674379523658630580977669
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 93:cc:a5:41:3f:26:09:5e:a0:0a:2d:e6:e1:dd:ae:9a:42:36:3f:3f
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 6d:41:c7:b5:c0:79:39:5f:16:dc:a7:32:87:b1:a8:c4:43:37:1b:74
Fingerprint (sha256): fb:7c:25:ac:74:e3:33:6e:b5:9d:99:f0:95:45:7a:db:42:5c:2e:43:16:06:45:e3:f5:8a:52:57:7f:ed:bf:2c

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.584.me

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for www.584.me

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.584.me

Other certificates including the domain name 584.me

(limited to 100 certificates)
584.me
584.me
584.me
www.584.me
584.me
584.me
sportsmedicinewestvirginia.com
584.me
584.me
zika.place
584.me
www.584.me
584.me
www.584.me
584.me
584.me
schober4texas.org
www.584.me
www.584.me

Certificate

The complete raw certificate details for www.584.me 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 322564537178701428674379523658630580977669
 . . . . . . . . [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 2019-12-04 18:01:45 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-03-03 18:01:45 +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.584.me'
 . . . . . . . . [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 773804849168521082788131167952956625063820984347951667139624763043199978502160566589089762349542304379857070564171674265629722224632234683152504552353197911167882587555194587015052130787277183445861992237726949827162743076654558450051038479603977645814997668580516224689485857370948879449540532090702352709908131190835939441622076917918354476234506423882863354652793895520402702044997168898827750031046170926399238260711174379970095666053216761804188284720255188237389333823989447964592762843738349699587056740487058134447445548509829839156926466479718606368623168318685570350136751478065836257309136537167263458111450132285083348248534798108619262630624018139932532362562771956722528875553640941377737844216754733004712326353065295801658921645622006644714585848902694805242219290952701147686623577816259964060481082213528149250750787663136742018374908871242962624822624033363330051699537989953656990301556482177132800886516604574834594798272855959693935283680104680667585131301602590476997066266749068882535778847126851090914630336621765262917915684920756371155844440812716907597465090732633092245351013370319125303490136302378585328817796089359079530924514406621358362953025409484085183305325406288154356944265650480056403975113411
 . . . . . . . . . . . . . . . . . . . . [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)
							93cca5413f26095ea00a2de6e1ddae9a42363f3f
 . . . . . . . . . . . . . . . . [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 (14 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.584.me'
 . . . . . . . . . . . . . . . . [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)
							00ef0075006f5376ac31f03119d89900a45115ff77151c11d902c10029068db2089a37d9130000016ed24a29e000000403004630440220691963bcee7cdee4026ab0c54ca2b140c2ba4868e9386936555b9ba251ae3bc90220570ef8f627fd07cc1b49a60c59ed0bbefd2632eb6158eedafd95737efb02d56500760007b75c1be57d68fff1b0c61d2315c7bae6577c5794b76aeebc613a1a69d3a21c0000016ed24a29dd000004030047304502206f93c081002473b84d274229a34d96d8d6722d870694779d95f698bad76b1796022100c8c434fd922bf1127c4d5a91b31ee6f5a60526920c28437748a7690101468fb1
 . . . . [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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