hybrid-rackmount-case.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:0a:27:24:34:16:ff:92:aa:04:4b:05:ee:11:d8:c9:8e:57 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=hybrid-rackmount-case.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:0a:27:24:34:16:ff:92:aa:04:4b:05:ee:11:d8:c9:8e:57
Serial Number (int): 264791709335520058496099599408656485551703
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: a6:88:dc:8b:1a:22:2c:d9:6f:c6:67:b8:34:75:4d:01:78:27:dd:a9
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 73:db:8b:49:1b:e4:c3:ec:5b:02:2d:65:86:78:01:ee:45:29:6b:3b
Fingerprint (sha256): 1e:be:08:1f:64:67:f3:bd:b4:5e:40:cb:85:13:4e:99:3b:d6:9f:c4:13:9f:ba:cb:18:02:49:3b:ff:e0:6c:14

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 hybrid-rackmount-case.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for hybrid-rackmount-case.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

hybrid-rackmount-case.com

Other certificates including the domain name hybrid-rackmount-case.com

(limited to 100 certificates)

Certificate

The complete raw certificate details for hybrid-rackmount-case.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 264791709335520058496099599408656485551703
 . . . . . . . . [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 2020-01-24 08:32:32 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-04-23 08:32:32 +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 'hybrid-rackmount-case.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 696786695855519056853210523713241128946483956808636762405344865947830238795333320875491011505727366458317579631237244721705358106596956002769075236287490696736758096418578618802616168577801829941619082952485958979042854830120578469788183187034382190816290047593493671165301282350959979530641184451074378829292474568298571941682832238611485646464186087387368461728050557121091314477522555869949644891244629758171470559939200374899495727002009991680928476259963115758069705872973097491643431049965893597530783171439095395093207552522092775695775499424690915165004204093094973823998136353758440224950452549023135592031122025453346986159544183610387606832194691187773995055531944343685298840474849070907844649305503064413855836623531817648021414267632780069504403090343755379867999073510098628007066139690836278933296284966428516716875691382665403215857938199696331623108340895036876106965461597748199771420626364974838172502645250930904290224529398509507270818248660924576237289954287406986456373288360407042521099583072952039719223653536017007014940860471777809823261902379813182793082129855857708137465671339747328679399951988054402560650813835214488210881999485996504851472721119784620910413365648227291998284674617229436088754528351
 . . . . . . . . . . . . . . . . . . . . [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)
							a688dc8b1a222cd96fc667b834754d017827dda9
 . . . . . . . . . . . . . . . . [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 (29 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'hybrid-rackmount-case.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)
							00ef00760007b75c1be57d68fff1b0c61d2315c7bae6577c5794b76aeebc613a1a69d3a21c0000016fd6e559de000004030047304502207c627d99064a3e832c92834ae7fa790b354e6ac4f0299faf430580c27517d39c022100b6f90a847ba74c1eb8b29a4935197b393fd77225cafb80554a4ffbaf67c111d90075006f5376ac31f03119d89900a45115ff77151c11d902c10029068db2089a37d9130000016fd6e55a57000004030046304402201d2fe9c38fe41015a016af368895cf3815bca78a4a4ddfafcf6e9a67d669903402201a5b44c129277d3caf5e269595903320eff2b7bc7e31c8d6026ae7d13461b7cf
 . . . . [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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