www.casalpusterlengo.org

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 04:bd:1d:3d:21:d6:5c:fb:84:ec:82:da:f1:0f:1a:0d:cd:82 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.casalpusterlengo.org

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 04:bd:1d:3d:21:d6:5c:fb:84:ec:82:da:f1:0f:1a:0d:cd:82
Serial Number (int): 412801376103387609753430165287287921692034
Serial Number lenght: 139 bits, 18 octets

SubjectKeyId: 3e:41:ed:63:40:0e:83:8e:bd:c1:1c:75:eb:30:6b:0d:41:1a:89:47
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): d7:b5:e9:ab:be:b9:56:82:89:ae:a2:54:06:22:02:03:0d:ab:e5:c9
Fingerprint (sha256): 0b:25:10:f9:e6:4b:6d:0e:5e:7d:3e:d7:10:08:ce:66:1e:41:35:d4:ab:1e:86:69:fd:98:48:83:49:89:cc:99

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.casalpusterlengo.org

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for www.casalpusterlengo.org

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.casalpusterlengo.org

Other certificates including the domain name casalpusterlengo.org

(limited to 100 certificates)

Certificate

The complete raw certificate details for www.casalpusterlengo.org 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 412801376103387609753430165287287921692034
 . . . . . . . . [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 2019-09-29 08:31:07 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-12-28 08:31:07 +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.casalpusterlengo.org'
 . . . . . . . . [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 710867174139849329692767279423997046042479344300459734534390650757035909209659375232310638830056259619342338759959867381428743309245552230017040126587075617887139792688749814917720929268644889507005914615965378844185543229003101359625151310408746909225974647692479550351887176930786773711828061921004348011734521340117338683181519611661605811420985720380352758704081864792362246829976872322181152128258115889723939473604026867700193811326391996761680988942220341152092888328360292909449702322892848568657284946162167605421383378796863056179569442740712410879004343868899045807258624951666834697013406236185799307080289441098950803102046307518325115954927337365780341189892214208434780388524566969512495895563483068751569632224937812990380148818764227071985646666286244806477082897949397308349285556207935824949866497696498460845580278242365736078686642895788007600026002566243135275300132484881211474108658224025739698023727777948186527199475201629033653088992364544464014491947701046480460303159823371971853790571161525265374985598117904766629152422203907479137749775914601383790752981266475756868103292593503673212474848375726592587459297710821663866278132966605000167488066594380161106808289186235232835253084955652878338411729843
 . . . . . . . . . . . . . . . . . . . . [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)
							3e41ed63400e838ebdc11c75eb306b0d411a8947
 . . . . . . . . . . . . . . . . [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 'www.casalpusterlengo.org'
 . . . . . . . . . . . . . . . . [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 (244 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (241 bytes)
							00ef007600747eda8331ad331091219cce254f4270c2bffd5e422008c6373579e6107bcc560000016d7c5c02a80000040300473045022100b956d3970b3c834d0f8270b0583384d236627b1edbcf65c7ca77dc9c852e1966022074b35ff40f28c926ae9865c47bca7bb69672e918c6fb3f8c1087dd681da9177d007500293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f4780000016d7c5c02ab000004030046304402205a074c332fe5ab8719fc5943d1299261c0cf58c4a284aea434204194ae070be5022049ad2222678e69b1148c34001d24964756c1a1b4eaab8133d18198859d25991d
 . . . . [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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