backend.agendaodonto.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:74:14:e1:ab:93:b6:d8:36:69:95:ec:78:40:d6:75:26:ea 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=backend.agendaodonto.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:74:14:e1:ab:93:b6:d8:36:69:95:ec:78:40:d6:75:26:ea
Serial Number (int): 300837368664813640126050171500729728313066
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 75:a8:a0:70:7c:dd:30:d1:5b:a3:b0:c6:30:47:35:ca:bd:40:81:2a
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): dc:f0:53:5e:8b:9a:3c:d8:2d:39:c1:e0:05:ca:ca:9d:68:bd:37:58
Fingerprint (sha256): 93:fa:8b:3b:d1:ee:31:6b:33:90:35:e2:aa:6a:0c:85:ea:b0:22:9e:8e:c1:83:74:e9:b8:81:85:fd:7b:1c:3b

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 backend.agendaodonto.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for backend.agendaodonto.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

backend.agendaodonto.com

Other certificates including the domain name agendaodonto.com

(limited to 100 certificates)

Certificate

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

Certificate (PEM)

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

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEA0zkxB/0Ls6p83kseO5bv
dovm4ZBsrcEGc43OS+wRjpqArVckzJhCPDP4QLrWuFie+Pzg3bJ/GesfLdKUZtlF
9veVi64yzV4C1ZUlOXVrLci20+l/wzKRriQUWGLMS5aarLIyt0MsK4XuB44Jb/lC
10/DHIibKef5nqXKnd4ho/Cy5GcjZJim9KKcqzHtXL4dL7FZ0zvfgiZJ089fiWIm
fUSs8QZjm7ZksBXsI7pwAraAEg/MKGZxTFUJyGW7dj+EX5QsWW7pW3c2u5fHysAi
8fR18v/XnocvOacaunHw5xYA3FC01gn5eoSSG93NZMZpBxPZsTlaighhO2kec3cx
xykCQjcodypcQeB1U4mlkFQqdabEUsOYtrFfwaW1wN1VD/VD2D9dNsJgV6L3M5UL
FhnWnHCR6zcVUpka7u7hqcC5+xHe4iWrJAkMDRYNXorYyynMJRpI4t0td+i5DZTB
2EwqL5jCn282ItTbNZJoYxvs6oyjRI5oAvv7tLIuNVDhoBM9wtyzzSHK9tMfhl9/
NsaLR/G2fPbBx6dpzgEZ1CNtNs2mJIW9lehpd0wCezsVIegfN4ynoiVx3lCAqF45
MRSKmJC61gaqCD7Ygbbjg0Tjf/8KAT4lYWrlbb9DDMYa+jGSullYzMrS6y/KogCp
QfvaGJej8bPKwv4spRxkSs8CAwEAAQ==
-----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 300837368664813640126050171500729728313066
 . . . . . . . . [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 2019-03-26 23:00:42 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-06-24 23:00:42 +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 'backend.agendaodonto.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 861716308815272518967504085126793441639730266019496574230642441391935378991383176544086403688128621012916911509667710122082404620824061852181353039493260674335380548007149304102597643644818888616921978008174706905196160092833953384995736546479307767952248756284873063294687518887153749700795910888455383915333842137851856154018462892430736064716878666233993350696330615897412478290766027558315634404729581912013655682697499572869567904368383390739001717904254947464425735864444393319012389168751199262344904127186076072645738207616599952640511601928560947018798463629434425261701213714031070081762096685532580970414228870573220938370698921393668400448224322856041264789323315736188570326408967289086847024386785075209991823691661362518245002586281750078131740017173791428770627105130798060233406221595945372726752789340895907109788387815528729652251275300093389475835306296504545233293365328085620177685584658851892960254200631621506652417313882505082424626331488637624473450140631411627253754375678275816372979530358964469548358929294359759813118697374784937110564078057912704814238305821741427054846959473147263693667431348636743820101948660561633315427440874012382045444328915802932600126591074082008522802194647952726124975639247
 . . . . . . . . . . . . . . . . . . . . [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)
							75a8a0707cdd30d15ba3b0c6304735cabd40812a
 . . . . . . . . . . . . . . . . [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 (28 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'backend.agendaodonto.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 (243 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (240 bytes)
							00ee007500747eda8331ad331091219cce254f4270c2bffd5e422008c6373579e6107bcc5600000169bc72efca000004030046304402200768fb163c9c2bf9cfed9d68022d6469c4dda5b418d11528a22056567b27ea57022057217c975c09caae0049b19225fdf2c4dc51e37e49b5c019ff352ee7df92eefc00750063f2dbcde83bcc2ccf0b728427576b33a48d61778fbd75a638b1c768544bd88d00000169bc72f25e000004030046304402207c7b8a71382a1a5048a0f497bbe25aebf6a003d3f705d02c6cd335e347abc96f022069a22a40e0a79f18f28366011c3e15e4a905feadd77acd44bb65ca47b57bdaa3
 . . . . [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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