idowa.plus

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:dd:ae:61:c5:c0:ce:ed:68:ac:88:aa:95:59:9c:dc:41:da was issued on by Let's Encrypt.

With 4 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=idowa.plus

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:dd:ae:61:c5:c0:ce:ed:68:ac:88:aa:95:59:9c:dc:41:da
Serial Number (int): 336771054219780533649311790770360587928026
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 02:34:92:3d:02:05:8e:ef:94:bd:96:77:d1:8c:ff:37:97:b7:9c:1f
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 1f:4b:4d:78:08:4d:be:4d:8a:9d:54:41:b5:d8:83:10:d8:a1:d3:49
Fingerprint (sha256): 0c:b6:01:74:6a:a3:4a:e4:fd:60:a7:59:a1:6f:44:77:58:cc:be:bc:0b:ab:8a:32:6f:b2:15:c5:74:fd:f5:53

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 idowa.plus

4

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for idowa.plus

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

idowa.plus
plus.idowa.de
service.plus.idowa.de
www.idowa.plus

Other certificates including the domain name idowa.plus

(limited to 100 certificates)
idowa.plus
idowa.plus
idowa.plus
idowa.plus
idowa.plus
idowa.plus
idowa.plus
idowa.plus
idowa.plus
idowa.plus
idowa.plus
idowa.plus
idowa.plus

Certificate

The complete raw certificate details for idowa.plus in PEM and ASN.1 format.

Certificate (PEM)

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

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAmRxAac0yuUYe15LGtlYG
LXeHnxX3X8EouFs9WfS9VJAaWoiz8DYzZ9vYkB50sDIU8axrAir3En18xkZZvn2T
SonA/2S5OkoMD1Xk6Guq+WO1XAM0p1k3a5NGYRylOnU6KBrShmSCvwWfFt9x30p9
eYrXSGRhjWbWRlHdxmEuqcoOlQOCgovR2LQZ1kmvrteWSPlML9gAdZIqSmiOV6AF
xKk6exINoHQ1MNTyMvIpfa54ivhOJRMvtwItaeKfFduZEfuRVE6GUcBdNwkadgk0
8d17RNPCKHDOasnYSrHLL5Ky/s0gUUZv837nXCdkYspJHbnuHmnhWV6YoLClddgs
MwIDAQAB
-----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 336771054219780533649311790770360587928026
 . . . . . . . . [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 2018-10-26 07:57:51 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-01-24 07:57:51 +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 'idowa.plus'
 . . . . . . . . [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 19328392050099417998686597771877752284493540092513525860294669784510611005164212393360658554516090778005452646457773449074367641810923671806349251613913431287212516782242493401970813800540284923221157024548728929680012727946204956088386880189337449655942666845017963656538008292806251037112510745061189465347460055534259545501009051110498881666998203157260002846961866112192958953347805282322716064921505353986981224665398052252301151804385371326659245938755207689773966061496253832503852700394859569357045155519860556961960116977964791911268080884790642542404473944397685129323042249665267542231943397849868201897011
 . . . . . . . . . . . . . . . . . . . . [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)
							0234923d02058eef94bd9677d18cff3797b79c1f
 . . . . . . . . . . . . . . . . [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 (68 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'idowa.plus'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'plus.idowa.de'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'service.plus.idowa.de'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.idowa.plus'
 . . . . . . . . . . . . . . . . [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 (246 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 1.3.6.1.5.5.7.2.2 (unotice)
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:12|false] UTF8String 'This Certificate may only be relied upon by Relying Parties and only in accordance with the Certificate Policy found at https://letsencrypt.org/repository/'
 . . . . . . . . . . . . . . . . [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)
							00f0007600747eda8331ad331091219cce254f4270c2bffd5e422008c6373579e6107bcc5600000166af9814ef0000040300473045022100e3e4982b86bf75e7e1f69d9cb5000c2c0adfbf4b3319379defce352e7acc4f5202201f3d40dd47d521d29d79a663f3efcf88033bb98af4fd7c0afcbaa1c4ce942faa007600293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f47800000166af98162e0000040300473045022100ab471df34071a7774dffb82a41bf80d485b26403a8382efd92978c2497f3d2080220425a5bb14d480995268f7afd03bd93b98594b09cd9297d6a31457fa1408f02a7
 . . . . [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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