goqii.com

Issued by Amazon RSA 2048 M01

About this certificate

This digital certificate with serial number 02:c9:0d:9d:e4:74:02:c1:2a:ee:a6:5f:e2:94:58:d7 was issued on by Amazon.

With 2 subject alternative names this certificate can be used to secure multiple fqdn's. This certificate is currently not expired, we haven't checked the revocation status of this certificate but you can do this simply on revocationcheck.com. 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=goqii.com

Amazon

Organization: Amazon
Country: US

This certificate will expire on

Certificate Details

Serial Number (hex): 02:c9:0d:9d:e4:74:02:c1:2a:ee:a6:5f:e2:94:58:d7
Serial Number (int): 3702383840984524952748894926954322135
Serial Number lenght: 122 bits, 16 octets

SubjectKeyId: 33:e2:7e:52:e6:b1:d5:39:7b:34:c5:bc:82:b3:55:06:dd:d7:f3:49
AuthorityKeyId: 81:b8:0e:63:8a:89:12:18:e5:fa:3b:3b:50:95:9f:e6:e5:90:13:85

Fingerprint (sha1): 7c:d2:a7:c1:f2:bb:83:70:3d:b4:b2:6d:de:24:1d:99:78:6c:8b:7c
Fingerprint (sha256): 47:16:40:df:7b:cf:a7:eb:70:b8:d1:08:85:cc:db:e3:b3:79:5b:c2:ff:fb:83:b5:e8:d7:6b:62:28:fd:9a:46

Issuing Certificate URL: http://crt.r2m01.amazontrust.com/r2m01.cer

Revocation information

OCSP Server: http://ocsp.r2m01.amazontrust.com
CRL Distribution Point: http://crl.r2m01.amazontrust.com/r2m01.crl

Check the revocation status for certificate goqii.com

2

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for goqii.com

Public Key Algorithm

RSA

Key Size

2048

Signature Algorithm

SHA256 with RSA

Key Usage

Digital Signature
Key Encipherment

Extended Key Usages

Server Authentication
Client Authentication

Extensions

10 extensions
No unhandled critical extensions

CA Certificate

This is not a CA certificate

Subject Alternative Names

goqii.com
*.goqii.com

Other certificates including the domain name goqii.com

(limited to 100 certificates)
www.classcub.com.au
goqii.com
*.goqii.com
www.evolui.ai
www.jajan-yuk.com
goqii.com
www.classcub.com.au
goqii.com
goqii.com
www.decodaapps.com
testfb.goqii.com
flairboat.com
goqii.com
goqii.com
*.goqii.com
www.ffstudios.com.br
www.balticgin.co.uk
goqii.com
www.ffstudios.com.br
testfb.goqii.com
goqii.com
goqii.com
www.mi-vino.app
testfb.goqii.com
*.goqii.com
*.goqii.com
blog.sarpdorukaslan.com
goqii.com
goqii.com
*.goqii.com
*.goqii.com
atualmultimarcasriopreto.com.br
jessemaxwell.com
atualmultimarcasriopreto.com.br
consiguetupremio.com
infections.app
goqii.com
*.goqii.com
goqii.com
www.videointerview.jp
cursoreact.com
goqii.com
apiv6.goqii.com
*.goqii.com
goqiicoach.goqii.com
cukaroodesign.com
www.floor17.dev
goqii.com
goqii.com
*.goqii.com
hillcreeknc.com
goqii.com
jacqueslenormand.com
www.jajan-yuk.com
www.floor17.dev
*.goqii.com

Certificate

The complete raw certificate details for goqii.com in PEM and ASN.1 format.

Certificate (PEM)

-----BEGIN CERTIFICATE-----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=
-----END CERTIFICATE-----

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAmdqFVAY90bA61rq7Ekl1
x3ESeIsnBgTenqnJTz1hCiSKFJZRhvsH5f0vXKxYuhBEf5FqnLrf4z3GiOWZ/KBn
PVqAJi3iv+JblBNQMTZC2EyRUHuJG1KogdRkjtKQPqYArHlQCobDcAvbA5Aj91cO
4I9ksI+pT0AyPRygdTPGx+eIThogKvf0AaB8omGmYdeSOFk1LiqPlntzKkgGlbNT
nhYi0ODA7Pr4BKuLpdGMgIUp9w1uiOy3JRdY9kCjGAnlnPdfb7RoYf7OUmgr1wF9
3C6xz1YJcuFITcK5yQtCIJQTh4QSzc2q0J6uUiTI/SjdK1HAtpR8l4HDMgJXgaSx
bQIDAQAB
-----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 3702383840984524952748894926954322135
 . . . . . . . . [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 'Amazon'
 . . . . . . . . . . . . [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 'Amazon RSA 2048 M01'
 . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2023-05-14 00:00:00 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2024-06-11 23:59:59 +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 'goqii.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 (2160 bits)
 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . [c:0|t:2|false] INTEGER 19422217289019504536040791903707486747497952027836990646737171904943257880093568425014730867580073449593160761718957964398782470946533044063706937608117495454635970848815794457555096328645715190945375284339473831800415009311752672851200314581792654133495669467137526541733528097921261585891621951398702685214803993567780702100510196587385936964346321533909216889752644308424445590954606906018397828892382004063774936002535542611500626648452421244489634339771323148905707723063844439879052148454221956526285170268314186868391082907230279606539481857590286986695044707261268534763505850244716911436632106500144933155181
 . . . . . . . . . . . . . . . . . . . . [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 2.5.29.35 (authorityKeyIdentifier)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (24 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|false] OtherName 81b80e638a891218e5fa3b3b50959fe6e5901385
 . . . . . . . . . . . . . . . . [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)
							33e27e52e6b1d5397b34c5bc82b35506ddd7f349
 . . . . . . . . . . . . . . . . [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 (26 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'goqii.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String '*.goqii.com'
 . . . . . . . . . . . . . . . . [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 2.5.29.31 (cRLDistributionPoints)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (52 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|true] OtherName 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|true] OtherName 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:6|false] IA5String 'http://crl.r2m01.amazontrust.com/r2m01.crl'
 . . . . . . . . . . . . . . . . [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 (12 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 1.3.6.1.5.5.7.1.1 (authorityInfoAccess)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (105 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.r2m01.amazontrust.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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://crt.r2m01.amazontrust.com/r2m01.cer'
 . . . . . . . . . . . . . . . . [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 1.3.6.1.4.1.11129.2.4.2
 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (366 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (362 bytes)
							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
 . . . . [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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