www.tropicks.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:da:a4:c2:55:d7:03:a0:03:d1:d1:80:77:f5:60:ac:2c:20 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.tropicks.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:da:a4:c2:55:d7:03:a0:03:d1:d1:80:77:f5:60:ac:2c:20
Serial Number (int): 335737416221984600086760508353760688090144
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 7c:2e:60:c9:aa:5c:87:6c:66:a5:74:51:e6:a6:a4:0b:9d:97:28:d6
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 33:5a:c2:a2:50:34:e4:4b:65:ee:21:de:01:8e:58:69:bc:d3:09:c9
Fingerprint (sha256): 9d:c7:98:b0:9a:ad:24:47:6b:62:a3:00:c6:1c:bc:f5:4b:c7:c9:9b:4e:ad:34:86:a2:ac:91:30:de:c7:86:12

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.tropicks.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for www.tropicks.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.tropicks.com

Other certificates including the domain name tropicks.com

(limited to 100 certificates)

Certificate

The complete raw certificate details for www.tropicks.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 335737416221984600086760508353760688090144
 . . . . . . . . [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 2019-10-13 03:06:28 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-01-11 03:06:28 +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.tropicks.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 719016473590889881121408353025156194532981293747410060863353890156623898538512992362399572503734138559408792901483847369925137576320871315494734239550645672370504452009947403204431750776031301026811811436327022166533287200104805646388979768031360553810559764601917827854359851162358331101800435477384753635977584096749309279774659512490516389987470316289194835101880950244591812286272120906915989100512791987374126608703025623920320033189113151693407260086618764478388340061948414436774210999873138198365297423132249502065149039135071001461964932127154620256347860015392773745365984902642908680515127926767649985754584173612687945770327277272822180058426589164485429557358469223367816317871139780296254798742433560190057871772672952499575709134383953865726986391536993041739670561582363451635193502251757391501619147451109015908905989984543146207333174870561715523325950275155892246659313703808596928590560622970261943341043892491311394168282005902037399247984795811457360837661780103742555685170006962709807464795381142668398636723215406178757687161298891065161113415521470914123535314706779268500392636958498531954849922256993015990194876015199156948629428193791444563269754426631589705450121592023918216057165014088349192435750371
 . . . . . . . . . . . . . . . . . . . . [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)
							7c2e60c9aa5c876c66a57451e6a6a40b9d9728d6
 . . . . . . . . . . . . . . . . [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 (20 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.tropicks.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 (246 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (243 bytes)
							00f1007600293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f4780000016dc34bcf2c0000040300473045022100a719d69a7e987494d23d15e6579622ebdeb969005094b934413f6473c133f2d0022014626b37d4229fcd7566cddff94684f0352e794e6420181d0311f175a1cd6aa9007700f095a459f200d18240102d2f93888ead4bfe1d47e399e1d034a6b0a8aa8eb2730000016dc34bcf3a0000040300483046022100e0b080ea13754a6b0c6fe930b874edc6b5bb4fd9febe6c59a44a0f58acaad87f022100fa8f32bcdfe896a3cc3c2084a4194ae8d077f2bed08fe584d00db9a8853cff78
 . . . . [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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