aisci-erfurt.de

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 04:a6:4c:ea:69:fb:b9:c2:e6:30:bc:de:ee:3c:76:f7:a1:6e was issued on by Let's Encrypt.

With 9 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=aisci-erfurt.de

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 04:a6:4c:ea:69:fb:b9:c2:e6:30:bc:de:ee:3c:76:f7:a1:6e
Serial Number (int): 405038255110658089797396589995365288616302
Serial Number lenght: 139 bits, 18 octets

SubjectKeyId: b5:47:94:78:83:87:82:67:12:d2:03:45:1e:45:8b:38:15:d1:c4:4a
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): e6:4b:0d:e7:15:df:bf:f8:00:e5:e4:a6:35:16:92:5a:61:75:a6:4d
Fingerprint (sha256): 8e:36:96:60:99:b2:b5:99:83:72:6c:5d:cd:be:aa:c6:3e:17:f5:7e:9b:90:94:39:48:9a:0c:36:b8:a3:0f:72

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 aisci-erfurt.de

9

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for aisci-erfurt.de

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

aisci-erfurt.api.itool4.net
aisci-erfurt.b01.itool4.net
aisci-erfurt.cron.itool4.net
aisci-erfurt.de
aisci-erfurt.f01.itool4.net
api.aisci-erfurt.de
backend.aisci-erfurt.de
cron.aisci-erfurt.de
www.aisci-erfurt.de

Other certificates including the domain name aisci-erfurt.de

(limited to 100 certificates)

Certificate

The complete raw certificate details for aisci-erfurt.de in PEM and ASN.1 format.

Certificate (PEM)

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

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxlOCJguY8kdKGjO1HlZE
ACX71KXTRED8Ma2BtR9Y3VFDVIpr2GLkX5v/LIE78COqWodZUjUqB3hKHQKFl74s
JygLGuJV+MQbaWHPwDLYglhNfFvRbuM1Wj588GLWSKiaYzaooiBssM2JLBJVTTJV
hg7SzytpaUAv4qUk1T+nCix+lDzUXAmt7jiGqkNX2XCh8RqXUXAtrd+1gSmQKmcF
VWNIQkd/DCASmP/tWdLAITkZ4TpsDt5WUSg6pywAPJrw3dRHLWEkhjppeyxY6YnM
GV++HznQ4Vh6vJDn7xIZTvToVa8BG4Xg7tt7yZvxn3eb+MM/s9iCjHzXCIP9r+eO
JwIDAQAB
-----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 405038255110658089797396589995365288616302
 . . . . . . . . [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 2019-03-25 01:01:25 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-06-23 01:01:25 +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 'aisci-erfurt.de'
 . . . . . . . . [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 25036363906662210712956611351044560635911598321972621189310509801409649528870419247636611039673054286039863438609660856142888767289700840557760548142166840312228420556695007582089593851823249826682616000168032155627826361684214786253582428366375989388264907838200989611541565509643655661647742212920233412093991433375357491642803045061790459022463565355321768754989695110990124968768060019057572454978782522097394574146922199032176437394894492039831496554707149310949659281751987310771352113349523590165725775420753580904128392584052981350434277180275706048614184981286620704339775828963584777255337428228717461081639
 . . . . . . . . . . . . . . . . . . . . [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)
							b54794788387826712d203451e458b3815d1c44a
 . . . . . . . . . . . . . . . . [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 (226 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'aisci-erfurt.api.itool4.net'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'aisci-erfurt.b01.itool4.net'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'aisci-erfurt.cron.itool4.net'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'aisci-erfurt.de'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'aisci-erfurt.f01.itool4.net'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'api.aisci-erfurt.de'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'backend.aisci-erfurt.de'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'cron.aisci-erfurt.de'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.aisci-erfurt.de'
 . . . . . . . . . . . . . . . . [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 (245 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (242 bytes)
							00f0007600747eda8331ad331091219cce254f4270c2bffd5e422008c6373579e6107bcc5600000169b294ba8a000004030047304502207e49bc32c8e834769d60d644119a825c3ae112fd0924b8ba8c70194ee57a0573022100f6bcf22775f428afcc2108708bab5e8a7af703f78c3371ab57d98eb069f1384800760063f2dbcde83bcc2ccf0b728427576b33a48d61778fbd75a638b1c768544bd88d00000169b294ba900000040300473045022020836793ec18c23c1cac2a41992d9cda83c9832b105c88d9af05958ff4b4808b022100c196a43e5ef9494e9996b6cc0f6b766bc2474a2264d88842eb8288533ac304cd
 . . . . [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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