ecorcardiologia.com.br

Issued by UbiquiTLS™ DV RSA Server CA

About this certificate

This digital certificate with serial number b2:37:26:be:fa:3e:e3:bf:1a:4d:87:6b:48:08:f6:c1 was issued on by COMODO CA Limited.

With 2 subject alternative names this certificate can be used to secure multiple fqdn's. 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=ecorcardiologia.com.br

COMODO CA Limited

Organization: COMODO CA Limited
State / Province: Greater Manchester
Locality: Salford
Country: GB

This certificate has expire since

Certificate Details

Serial Number (hex): b2:37:26:be:fa:3e:e3:bf:1a:4d:87:6b:48:08:f6:c1
Serial Number (int): 236888945439297538728714510387955431105
Serial Number lenght: 128 bits, 16 octets

SubjectKeyId: 16:f5:3c:cc:2c:fc:a9:fd:e8:9a:df:0c:e3:c7:ee:d3:47:ff:df:d7
AuthorityKeyId: 38:12:c6:79:02:66:38:02:e3:37:24:e5:8b:0f:ff:45:95:69:e6:31

Fingerprint (sha1): 58:95:40:fe:62:78:cf:60:46:89:50:b1:32:ce:7c:7f:54:82:57:1c
Fingerprint (sha256): 36:80:26:0d:91:e4:16:a3:38:11:f0:c3:49:cb:87:ad:3e:42:b0:3d:f3:66:1e:51:34:ca:74:9f:7f:c6:24:15

Issuing Certificate URL: http://crt.comodoca.com/UbiquiTLSDVRSAServerCA.crt

Revocation information

OCSP Server: http://ocsp.comodoca.com

Check the revocation status for certificate ecorcardiologia.com.br

2

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for ecorcardiologia.com.br

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

9 extensions
No unhandled critical extensions

CA Certificate

This is not a CA certificate

Subject Alternative Names

ecorcardiologia.com.br
www.ecorcardiologia.com.br

Other certificates including the domain name ecorcardiologia.com.br

(limited to 100 certificates)
vdon.com.br
ecorcardiologia.com.br
ecorcardiologia.com.br
ecorcardiologia.com.br
ecorcardiologia.com.br
ecorcardiologia.com.br
ecorcardiologia.com.br
mbravim.com.br
ecorcardiologia.com.br
ecorcardiologia.com.br
www.ecorcardiologia.vdon.com.br
ecorcardiologia.com.br
ecorcardiologia.com.br
ecorcardiologia.com.br
ecorcardiologia.com.br

Certificate

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

Certificate (PEM)

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

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAt1pMsObrBT8YHlQOWHmy
iVKt1WmMc7CO17hwNf0SgznUN03MnS76KGl08pR8gg6RFxanCGn9RCQdUZelNddC
ksVsqwUJ5D9M8CG/M+yC3DdTOHdPsRPBdDkj1WL4xYy/Sa1N7Iz2b7yhnKXyPmfv
G5lDn+hFMQx75wBtWsEVsQQA7CJOykr8qtXpaogM8g0sPQVFkU0XSdieQOQ+52v3
VlUiKpVFQ2/6/15vjs+/pn8jEg9D5uZDrvoVZmYV/WB+UJ7eSIzHKwDuEFL/hr0+
CsQQylSIfTTDrDVAC8g6tOp8p3h170UtRwA6f2WQLVEeKL7xuLN2c56yJRRhqmYw
AwIDAQAB
-----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 236888945439297538728714510387955431105
 . . . . . . . . [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 'GB'
 . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF 
 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.8 (stateOrProvinceName)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Greater Manchester'
 . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF 
 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.7 (localityName)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Salford'
 . . . . . . . . . . . . [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 'COMODO CA Limited'
 . . . . . . . . . . . . [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:12|false] UTF8String 'UbiquiTLS™ DV RSA Server CA'
 . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2018-08-29 00:00:00 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2018-11-27 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 'ecorcardiologia.com.br'
 . . . . . . . . [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 23146138188476754370530005076181104756429976589781690025987393596798126543347332242989380780153447564955790398812576803397583133098361757764408769399222526910815248047552669737174091189589770142832476078694468703466338300183315853194277298263789577903602717458962708915971204196253213101755828973063598937410644687278525838251296032384479113119219852208697181074330891910466654916343148033030083120585607079363514971369230376556933988632152715594087116756823382169258663002593156017605170978995125806247817734720819936319564274637927723620640270577924113468244561510050547388496100393214761166283070795201947344711683
 . . . . . . . . . . . . . . . . . . . . [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 3812c67902663802e33724e58b0fff459569e631
 . . . . . . . . . . . . . . . . [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)
							16f53ccc2cfca9fde89adf0ce3c7eed347ffdfd7
 . . . . . . . . . . . . . . . . [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 2.5.29.19 (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 2.5.29.37 (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 2.5.29.32 (certificatePolicies)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (73 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.4.1.6449.1.2.1.3.4
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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 'https://secure.comodo.net/CPS'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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 (104 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.48.2 (caIssuers)
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:6|false] IA5String 'http://crt.comodoca.com/UbiquiTLSDVRSAServerCA.crt'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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.comodoca.com'
 . . . . . . . . . . . . . . . . [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 (54 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'ecorcardiologia.com.br'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.ecorcardiologia.com.br'
 . . . . . . . . . . . . . . . . [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)
							00f0007600ee4bbdb775ce60bae142691fabe19e66a30f7e5fb072d88300c47b897aa8fdcb00000165875093e70000040300473045022069194a00d97017e5d32cce5f1be1803870d0f330abc1d2bd626b509a6e51ef83022100b16fa437d6de99e2a82fdd13e54bf6330d2140c18acaafd68c597d9723ecdc79007600db74afeecb29ecb1feca3e716d2ce5b9aabb36f7847183c75d9d4f37b61fbf64000001658750987e00000403004730450220269aa2fabbabfb0562f269587d207312150a743b30a346468c6cd4d45043eae4022100f9acc80b019b4590b016bfe6d6c09878fc6a94c7d8df08c9f8d7b08a630a1028
 . . . . [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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