chicagocateringservices.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:73:21:de:51:79:c8:12:8d:e4:6f:d7:bf:7d:c2:33:34:9c 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=chicagocateringservices.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:73:21:de:51:79:c8:12:8d:e4:6f:d7:bf:7d:c2:33:34:9c
Serial Number (int): 300514348857475865186407039885072747672732
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 88:d8:2e:48:e9:42:0a:5b:74:e5:e0:b6:16:d9:29:0f:d0:34:45:06
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 0e:74:d5:4b:75:1b:a6:5f:8d:dd:31:45:58:11:7b:e2:c9:12:a5:d4
Fingerprint (sha256): 27:d2:01:c0:b3:41:8d:d2:e2:58:53:f1:99:ee:61:b5:0f:22:70:ac:08:9c:7b:83:e1:4d:fe:7d:55:c3:a2:c2

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 chicagocateringservices.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for chicagocateringservices.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

chicagocateringservices.com

Other certificates including the domain name chicagocateringservices.com

(limited to 100 certificates)

Certificate

The complete raw certificate details for chicagocateringservices.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 300514348857475865186407039885072747672732
 . . . . . . . . [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 2019-06-12 19:13:10 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-09-10 19:13:10 +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 'chicagocateringservices.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 803397268841989836082512526110946770846092557654728411029802534947252014720640754320044523964201958928265583766725941273980467669285880926591557569894459189266961408244276887972729758331979100900868743443538359489611501611178240852242883682712798962584813608725434992989369536258184667764847216893553653141934649025518361825109704864672616616068490762011586585386160168673755893459558187623569453070013135827273735489128028816287673287514523191315165970303784607369991587753564242872973004157147865842736143612736966274234727186365270072438124817791069897114754006921285713456644330083327458972799297493040861462723326722566268812361180675743848182742502832800208796727650947851194926578118396454455679807259755247438638260808635360263213031067000469097192780829696987276684154363704284364299447326325487233938275599571478781668250809420584464031588145870836618858028088304952651858252982860157529977169625770424031672160527229440433871606768543346277444598449144784530339326176904293070077919579076425695755430850291503214057893343774043891850388994299329322558528576099323833450397051131317272430356358272973191801278323889683195149819182111346045357758640702324532749252069016124194172650936567276610969681782816534085656951268207
 . . . . . . . . . . . . . . . . . . . . [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)
							88d82e48e9420a5b74e5e0b616d9290fd0344506
 . . . . . . . . . . . . . . . . [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 (31 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'chicagocateringservices.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 (245 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (242 bytes)
							00f0007600293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f4780000016b4d52a668000004030047304502206b86afea1be7e04a841677b66622bb8d0eb26f9c386d3fe35f74203bacf8d1d70221008781d3bc77e78004d6d05c9ecc745da571380e92cf1e0ed1c5ba437b200b45b80076006f5376ac31f03119d89900a45115ff77151c11d902c10029068db2089a37d9130000016b4d52a80a0000040300473045022033ea434a9f2ad7dc28e4ee487783d1e8ef7b27c1a915bacc98e0e5983ee141ab022100bf10eb92ef56ac08423286bb2076b35b1845c83a23042f3fd5b8a51b245c805a
 . . . . [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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