www.sustinente.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:e8:75:3d:85:b1:a7:c2:11:5f:61:31:4c:8f:49:2d:3b:96 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.sustinente.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:e8:75:3d:85:b1:a7:c2:11:5f:61:31:4c:8f:49:2d:3b:96
Serial Number (int): 340438206038189449905975491580535931485078
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: ff:7b:9a:96:a1:d1:e6:b9:dc:11:63:80:4a:40:53:00:f8:22:4d:fd
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 88:a5:c7:34:a2:1b:6b:07:34:11:ac:1c:c0:e6:3c:bc:35:52:9e:b4
Fingerprint (sha256): 0e:5f:af:8e:eb:72:83:1e:3b:09:8f:96:27:f9:14:07:5e:56:b4:7a:c0:50:30:d0:4e:24:a1:55:84:37:0e:75

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.sustinente.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for www.sustinente.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.sustinente.com

Other certificates including the domain name sustinente.com

(limited to 100 certificates)

Certificate

The complete raw certificate details for www.sustinente.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 340438206038189449905975491580535931485078
 . . . . . . . . [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 2019-12-17 23:47:11 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-03-16 23:47:11 +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.sustinente.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 689252487141797110513811891270666391447892044010930145220329235524272398131089499808163523784004972751538289116194777919881399663630481481815433242970993426625764706216252568745602709502310674597840400934350336770850418476842635510833307642301945684347268690887379741289071772764345457696917423929625070529770993185163654044454844321936136639065189613198921967682038063814041222663337668042352796967319358175733462188789541363772900326243437476550136739430600822876748789639642653131096639843743170986415682879231973795858332130574133351103181224523567954433502243229150977785984041865623752558894161502266586531467629166801897866037910021094875245212517118361910870381402471945906587390841233884017179459097109876140320246793763316486759950261230987336138304278439869908771292267097697713182861515656669923960191493887602488207858843704761940772294041913464518961934525809701478883837253072618335023890918887727265376361277993740289500379480739920523263595130009741637803898226592557671506103147430596810273985560791612380220400732691454938084984875327062483295260472724596385208564736377745420035405616819653132639369926295338491630448020670611988840489481507925407220709709438000219431943736079369527031040904461841822869932083691
 . . . . . . . . . . . . . . . . . . . . [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)
							ff7b9a96a1d1e6b9dc1163804a405300f8224dfd
 . . . . . . . . . . . . . . . . [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 (22 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.sustinente.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)
							00f0007600f095a459f200d18240102d2f93888ead4bfe1d47e399e1d034a6b0a8aa8eb2730000016f1679147e00000403004730450220013e4bbd0c1d119c89f4860e8c4d12858044356aa3f2841a1923d8c052339cd2022100c1d34ab21cf3d854bedc62a389f5bdadc26e2d7608f5a2d7bc3ef057e0cff4e6007600b21e05cc8ba2cd8a204e8766f92bb98a2520676bdafa70e7b249532def8b905e0000016f16791472000004030047304502204397fd64307e26e35ed377090f1cb9fbe3e5637ff4cea0934ba0db67e5c5bcb00221009d13fbce1f3a9cca08989b999b247e3afa0a3599c11a8d195ec4364250186ada
 . . . . [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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