www.gayscottsdale.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:f2:5f:9b:70:06:e0:9e:8a:b6:e6:44:a3:8d:58:4e:4c:a4 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.gayscottsdale.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:f2:5f:9b:70:06:e0:9e:8a:b6:e6:44:a3:8d:58:4e:4c:a4
Serial Number (int): 343812274327935248895829265942381702565028
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 0f:8f:76:d0:f6:a7:0e:e4:a7:a7:00:6e:2f:90:7f:78:cd:d3:4d:a0
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): b0:4b:09:0d:c4:fb:3e:e6:b2:0d:86:86:90:f4:e9:86:71:ca:f4:fe
Fingerprint (sha256): 0e:e7:0e:8c:3c:f7:a0:1c:be:01:50:e1:65:42:a0:80:9c:dd:70:1d:68:61:d5:2f:99:4b:e1:6d:10:f9:2b:3a

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.gayscottsdale.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for www.gayscottsdale.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.gayscottsdale.com

Other certificates including the domain name gayscottsdale.com

(limited to 100 certificates)

Certificate

The complete raw certificate details for www.gayscottsdale.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 343812274327935248895829265942381702565028
 . . . . . . . . [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 2019-08-25 14:24:38 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-11-23 14:24:38 +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.gayscottsdale.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 736473237297851163904189291191663317009964305240473237784355528178860387496213991038522430675073424578137608485035606818337434185245453255742099996472917275045277521356739607438567822385990224109802193937540747338574427735110840343556074015133090377342427120772587557493310858010868601028905883569888593413202418061068814782441191832702275215203755623343585090946506830651695771210381277600115909225750807757716244695081455910019436268245009514853849930986699860936849815273976918899428376187563160555826823807535998101094996039807421494618764620585418208954461415970938250745606263976385304004652061416885688582265393018233675174518830792077403141015138450059156465572896108533761601264822342888487275095940992215773348982372319198312805050515891429552296508977047567143387892452956236496261383775673835105654747069128155436287476821796953820813452913191723175504399634076703769811124973468506173943845309296267331262773965462420263620765681035757397910622197202219161145719643640127821579469985089029394060940780054800095915096441921585299547555448040453954186564454069121981645615243014593675028505849092990015550011393268067362034030583379439123527172705818246616272806531298301452843326394589222043024511631372074865339727464829
 . . . . . . . . . . . . . . . . . . . . [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)
							0f8f76d0f6a70ee4a7a7006e2f907f78cdd34da0
 . . . . . . . . . . . . . . . . [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 (25 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.gayscottsdale.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)
							00f0007600e2694bae26e8e94009e8861bb63b83d43ee7fe7488fba48f2893019dddf1dbfe0000016cc9611413000004030047304502205977a94c7567a520b1f8bef649893937b47c47d915cbe1322f70f4d25741da1c022100bfbf9da28544febb617ca3852552486c9b1c07b6f58d45086468f3b7a5e71130007600293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f4780000016cc9611434000004030047304502210084c67952016b648d2f66900abe0059cf9990e5e8268dcd46a5a0e2617e3c111c0220716c08b5cdf3005df8dc61f7af57c0070629691a371c693ff2e2214db9504705
 . . . . [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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