casalpusterlengo.org
Issued by Let's Encrypt Authority X3
About this certificate
This digital certificate with serial number 03:d0:b6:c0:a3:8c:8a:9d:45:f4:3b:fd:4d:49:00:95:06:89 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=casalpusterlengo.org
Let's Encrypt
Organization:
Let's Encrypt
Country:
US
This certificate has expire since
Certificate Details
Serial Number (hex): 03:d0:b6:c0:a3:8c:8a:9d:45:f4:3b:fd:4d:49:00:95:06:89Serial Number (int): 332358509848233240926303714644618502276745
Serial Number lenght: 138 bits, 18 octets
SubjectKeyId: 16:d4:42:ac:be:a0:21:d1:4b:f6:a7:50:37:4e:a5:bf:46:66:82:29
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1
Fingerprint (sha1): a5:7b:5e:69:f5:1d:01:7e:ad:c2:a8:8f:fc:cc:47:b8:88:3c:2a:15
Fingerprint (sha256): 0f:ed:f0:10:bd:04:13:66:47:2a:90:c8:ef:72:53:dd:5f:f4:91:ea:e3:09:4f:90:e8:0a:eb:20:e2:34:52:93
Issuing Certificate URL: http://cert.int-x3.letsencrypt.org/
Revocation information
OCSP Server: http://ocsp.int-x3.letsencrypt.orgCheck the revocation status for certificate casalpusterlengo.org
1
DNS Names
0
Email Addresses
0
IP Addresses
Advanced Certificate Properties
Tehnical certificate details for 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
casalpusterlengo.org
Other certificates including the domain name casalpusterlengo.org
(limited to 100 certificates)
www.casalpusterlengo.org
casalpusterlengo.org
casalpusterlengo.org
casalpusterlengo.org
www.casalpusterlengo.org
www.casalpusterlengo.org
www.casalpusterlengo.org
casalpusterlengo.org
547.me
www.casalpusterlengo.org
www.947.me
casalpusterlengo.org
theologians.club
casalpusterlengo.org
www.casalpusterlengo.org
casalpusterlengo.org
casalpusterlengo.org
casalpusterlengo.org
www.casalpusterlengo.org
www.casalpusterlengo.org
www.casalpusterlengo.org
casalpusterlengo.org
547.me
www.casalpusterlengo.org
www.947.me
casalpusterlengo.org
theologians.club
casalpusterlengo.org
www.casalpusterlengo.org
Certificate
The complete raw certificate details for casalpusterlengo.org in PEM and ASN.1 format.
Certificate (PEM)
-----BEGIN CERTIFICATE----- MIIGYTCCBUmgAwIBAgISA9C2wKOMip1F9Dv9TUkAlQaJMA0GCSqGSIb3DQEBCwUA MEoxCzAJBgNVBAYTAlVTMRYwFAYDVQQKEw1MZXQncyBFbmNyeXB0MSMwIQYDVQQD ExpMZXQncyBFbmNyeXB0IEF1dGhvcml0eSBYMzAeFw0xOTA3MjgyMzU2MjBaFw0x OTEwMjYyMzU2MjBaMB8xHTAbBgNVBAMTFGNhc2FscHVzdGVybGVuZ28ub3JnMIIC IjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEAwkdhsThUpdGjM3lX0eJDQKfU ooFOd3OxnsAtNtsdcdVx2wASMlXV3d4SiasRCraIzoNGoMOK40V+dzJKFp4zDt9n DUOMElH+VcXzFLgNuVtDUiSmOvSUwfrLlCD6zOxMkNNnhihxM3+8jzcix7atJx4X 3DzTJAJremEGGzHDdSzXayKFYlZI8TMzg0ygIItOCOocm/9od+UIp1IP+kHaFeEm ViLl8Ri009AskndfW+lYdgPfcWXvkNL7o0LxjG7/cMCZPMSinJqxVp+Q5HAVV+Gt jGomLIbrQv3TOzfMnp6TNSviB3ldpRUVb5l28wFVoHBm6YjuvPrUDWa0ZRbmsmDV B+YFopymY5ql0MZ50q6D2km6huSVBFy52Dk/3tN0zRwXp96INYXKnw4XcbGCM/1e 5y9tgI/5ZFnQdPNd/Kufmxj9yF6C212CtiGtS+n849PkdgwWbpD6vMorHqHMXIQa 2R7FMOxBVlcrj8g7wm/dzvo9ZXSE2kbf+I9oGF0Bb6OOhnadaIsGso16q9xTFoa4 9iZPgyeJ1WlLKTUijSDmD5LeXYjIywsQIABPorzOmGeTJDj08MOrlVRDYltX/QXB s/giokOhB6h7dmdCCbrgpgJLj0MH80ESXhIvk+gvFxrTKaj9WMgpku8dSTTofGG1 iJ0RCUui1DD9wCcRG8MCAwEAAaOCAmowggJmMA4GA1UdDwEB/wQEAwIFoDAdBgNV HSUEFjAUBggrBgEFBQcDAQYIKwYBBQUHAwIwDAYDVR0TAQH/BAIwADAdBgNVHQ4E FgQUFtRCrL6gIdFL9qdQN06lv0ZmgikwHwYDVR0jBBgwFoAUqEpqYwR93brm0Tm3 pkVl7/Oo7KEwbwYIKwYBBQUHAQEEYzBhMC4GCCsGAQUFBzABhiJodHRwOi8vb2Nz cC5pbnQteDMubGV0c2VuY3J5cHQub3JnMC8GCCsGAQUFBzAChiNodHRwOi8vY2Vy dC5pbnQteDMubGV0c2VuY3J5cHQub3JnLzAfBgNVHREEGDAWghRjYXNhbHB1c3Rl cmxlbmdvLm9yZzBMBgNVHSAERTBDMAgGBmeBDAECATA3BgsrBgEEAYLfEwEBATAo MCYGCCsGAQUFBwIBFhpodHRwOi8vY3BzLmxldHNlbmNyeXB0Lm9yZzCCAQUGCisG AQQB1nkCBAIEgfYEgfMA8QB3AOJpS64m6OlACeiGG7Y7g9Q+5/50iPukjyiTAZ3d 8dv+AAABbDs6byoAAAQDAEgwRgIhAM24jhNxjwtR9tt5sxGyFSRmYCjaEWZpusWl Mb9ejV97AiEA38vRu/tgknuLUCAs4KsNclz0aaHpYs8/84eeTYAozfQAdgApPFGW VMg5ZbqqUPxYB9S3b79Yeily3KTDDPTlRUf0eAAAAWw7Om9NAAAEAwBHMEUCIQCo 1Z3VPObxKQNUnKb9eE+6wgKT1SYQdXM1IJWREabjpAIgHC2QvnbSB0j4FsjKMYfO RGZK3ZtEn7iTBC3C2MSU4W0wDQYJKoZIhvcNAQELBQADggEBAC1nVmD5c0Ro9B1c CCDZnj35doJozovZLJGsdnylSb/2dOHc3TEj11A0TMHBbFB2R3SeJnZdHGTpGSfE UZaplMB/Fty2kSTkf9W/pFV90gLxgitKI4oLpRbcYxD9XMCkL1Jc4TgQu8t0E5au J5YwB6CPYD6+WVsKqVe/QhlRtGQhLey9DG0cT5vdz+T9dYWcEhZSP//Yvz7517t0 TnMNG9/7GrzPaA5UXYkBm5khMk5LAmwFTShKj6pmqDaoxw+jCyWv3LKPP0F1Sk/T I2LVyvSoydXH//G2MpxegDjbgfBfQ1tl2GOEjmE/TtyXnfVw9Gcn+CAcuyMUA3v8 PUYPu/I= -----END CERTIFICATE-----
Public Key (PEM)
-----BEGIN PUBLIC KEY----- MIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEAwkdhsThUpdGjM3lX0eJD QKfUooFOd3OxnsAtNtsdcdVx2wASMlXV3d4SiasRCraIzoNGoMOK40V+dzJKFp4z Dt9nDUOMElH+VcXzFLgNuVtDUiSmOvSUwfrLlCD6zOxMkNNnhihxM3+8jzcix7at Jx4X3DzTJAJremEGGzHDdSzXayKFYlZI8TMzg0ygIItOCOocm/9od+UIp1IP+kHa FeEmViLl8Ri009AskndfW+lYdgPfcWXvkNL7o0LxjG7/cMCZPMSinJqxVp+Q5HAV V+GtjGomLIbrQv3TOzfMnp6TNSviB3ldpRUVb5l28wFVoHBm6YjuvPrUDWa0ZRbm smDVB+YFopymY5ql0MZ50q6D2km6huSVBFy52Dk/3tN0zRwXp96INYXKnw4XcbGC M/1e5y9tgI/5ZFnQdPNd/Kufmxj9yF6C212CtiGtS+n849PkdgwWbpD6vMorHqHM XIQa2R7FMOxBVlcrj8g7wm/dzvo9ZXSE2kbf+I9oGF0Bb6OOhnadaIsGso16q9xT Foa49iZPgyeJ1WlLKTUijSDmD5LeXYjIywsQIABPorzOmGeTJDj08MOrlVRDYltX /QXBs/giokOhB6h7dmdCCbrgpgJLj0MH80ESXhIvk+gvFxrTKaj9WMgpku8dSTTo fGG1iJ0RCUui1DD9wCcRG8MCAwEAAQ== -----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 332358509848233240926303714644618502276745 . . . . . . . . [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 2019-07-28 23:56:20 +0000 UTC . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-10-26 23:56:20 +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 '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 792588494365779902475194577948777841568788275147727989258046753670848692921165496978011286546230115106602741130545922463566933325231625880950839089979951521988047063621577489188992196497000359406458346652704589356106400538348607684743378982113170794484007171197323490169264748651535503975240234873104457084379227208084946520883367160138698192763208511765445263194645841408293651344447878421543190269720533775776022660649978382445248962008577501254159489645732059242805288476500653281324348368483329091904793159297359492980255732992946259207220618268727324331838412253790108048848014849253512546261706775669459860591525716162447825353140848226214821801561900461767699186093979273363307430708295846850611947653170861857524835902599210101043224837715592008254243707692310894989579023141115464926088672931688150885555447604065289642651823665080084240273191118037573874418762724501022480106612663432818300925413877310432006734438258530186338810621889537828258820097102194692185728548987506124567200341140175497351087589999095122159861152183422717727077100470269634053410704843166454560791911404116198728124060124368728891115818212839741545855774752680632785751154756136448794386559823069274469927396429898516252302565335007715953678031811 . . . . . . . . . . . . . . . . . . . . [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) 16d442acbea021d14bf6a750374ea5bf46668229 . . . . . . . . . . . . . . . . [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 (24 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String '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 (246 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (243 bytes) 00f1007700e2694bae26e8e94009e8861bb63b83d43ee7fe7488fba48f2893019dddf1dbfe0000016c3b3a6f2a0000040300483046022100cdb88e13718f0b51f6db79b311b21524666028da116669bac5a531bf5e8d5f7b022100dfcbd1bbfb60927b8b50202ce0ab0d725cf469a1e962cf3ff3879e4d8028cdf4007600293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f4780000016c3b3a6f4d0000040300473045022100a8d59dd53ce6f12903549ca6fd784fbac20293d5261075733520959111a6e3a402201c2d90be76d20748f816c8ca3187ce44664add9b449fb893042dc2d8c494e16d . . . . [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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