cassis.co

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 04:0a:45:73:e5:4f:e6:69:35:4c:2d:d4:3d:4f:25:a7:69:d8 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=cassis.co

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 04:0a:45:73:e5:4f:e6:69:35:4c:2d:d4:3d:4f:25:a7:69:d8
Serial Number (int): 351944285893100394737557044907896130202072
Serial Number lenght: 139 bits, 18 octets

SubjectKeyId: 47:29:26:a9:af:1e:4c:97:15:21:19:53:50:1e:e1:aa:86:46:16:45
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 7c:80:69:61:0d:03:a8:5e:cf:5c:4d:a1:27:25:d3:59:27:05:26:56
Fingerprint (sha256): 3d:74:09:f3:ac:8a:07:78:b2:2e:d8:dd:69:2d:13:e3:1b:18:01:36:49:83:c5:c8:df:5a:27:d7:98:b1:d7:e1

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 cassis.co

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for cassis.co

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

cassis.co

Other certificates including the domain name cassis.co

(limited to 100 certificates)
cassis.co
cassis.co
cassis.co
www.chiefs.co
www.cassis.co
loris.co
cassis.co
www.filiberto.co
bellydancer.co
cassis.co
www.thecannagar.co
cassis.co
cassis.co
cassis.co
www.cassis.co
ostomates.co
cassis.co
cassis.co
www.kevo.co

Certificate

The complete raw certificate details for cassis.co 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 351944285893100394737557044907896130202072
 . . . . . . . . [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 2019-01-08 11:58:10 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-04-08 11:58:10 +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 'cassis.co'
 . . . . . . . . [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 795544401471079736665378345988670854896082864473912580611968130568923173541999436410912360112319767402198589081027379124022580044613170049827652045878130417251071850045568388044235744466767790956028242294346784100383597509327347134905826793503456252271498997276883643882196560351881940053301660043375222151609115512616156546321348306582562147129531369735913082192745830102516197609977059345681704533768674350824448314893289214621898244218635921196066218073141206908385904971661349787266891429858787911174807935499255586208752103315884692017603407490533308631402426264228271278666608402444046267158236402658590523202131769963071791713962944710525459692581243935815324956288567672654569683547699154023897440523481886771940663706449439888287343154898917996539613092570929325589175493623580606845734879343864136536953941729591059547666136354623900731609311907934764508302524140304857613430725279943849607533902008011669969104509210328649036583991636136511718641980584782417559470306301496461519703572761260981664084714672565718802562886084136507554584759956568044655980661566234936080039917149364276061702025389339688887317467604303170593466187740281603187261494361460810546885067870768106297625928525483352723887513050065590778996984671
 . . . . . . . . . . . . . . . . . . . . [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)
							472926a9af1e4c9715211953501ee1aa86461645
 . . . . . . . . . . . . . . . . [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 (13 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'cassis.co'
 . . . . . . . . . . . . . . . . [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 (245 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (242 bytes)
							00f0007600747eda8331ad331091219cce254f4270c2bffd5e422008c6373579e6107bcc56000001682d8ab22b0000040300473045022100ff8acb0205620fdd17b88d0182d606c660cec06be356d42fabcd454b108354e9022053ef6d5e283cba4c5ec2d0201117dbff37f73a93f8b3757852c80882d4820602007600293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f478000001682d8ab24e000004030047304502207f7cb1775208d4276599c42242692f82a966ae8f5772b3a79f3dadec79a46012022100b2bccaa3f1218f79e1633b622d67dc86f07a714ad578d198b2e3e61d7b16ba62
 . . . . [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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