iws.isuzu.com.pl

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:29:ea:36:33:5f:19:29:bf:da:b2:8c:b1:c8:77:20:f9:fd 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=iws.isuzu.com.pl

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:29:ea:36:33:5f:19:29:bf:da:b2:8c:b1:c8:77:20:f9:fd
Serial Number (int): 275599755616020600959122184720299593890301
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 1d:11:48:e6:86:9d:45:c6:69:fb:8e:b7:8d:d6:b8:c5:dc:da:b9:49
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 6d:90:b2:73:17:cd:f9:41:59:6f:7c:bb:23:0c:45:f1:76:aa:76:20
Fingerprint (sha256): ee:b1:9a:c1:69:43:0b:8d:88:a1:b7:dc:2b:0d:37:0c:f9:df:ca:db:86:01:87:73:f7:d9:ee:94:54:e8:3d:d2

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 iws.isuzu.com.pl

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for iws.isuzu.com.pl

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

iws.isuzu.com.pl

Other certificates including the domain name isuzu.com.pl

(limited to 100 certificates)

Certificate

The complete raw certificate details for iws.isuzu.com.pl 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 275599755616020600959122184720299593890301
 . . . . . . . . [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 2019-12-29 06:54:32 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-03-28 06:54:32 +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 'iws.isuzu.com.pl'
 . . . . . . . . [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 1006074581720201414783336466744397993155417034532393833513386769839397743151699618860720246484271840865801757545895470215748764149079901764530715961197406257364657948291542090561271530077763963528462244946148016246663604021013561754337298895189475376447243128261410269610604795283748396371320761742785530108885116479843760960119600481907204354227352657775981449627876231311990283085487896593449908642150190415232652724936904030513554774121769999062923334716091210987424650482388641885882773432172826452067282768770573146678246536519143526092723368036835370505016823671049294610400764692815937252568223580960075234569140117538254753031378725984778427539019595287283383054259937289753042627367551037253726280995809261133753268014361676975738078872950793169948301770054258562296536714307425691062530553387980879476573076052423339111208109927153308065873753814287947149834076712720926740967817894318553117563226089578101317492093511447960496991482432117167872555422824467708299121723687288862160679173984533196787022141830864001303286161713734562162884853207428133205181614327682897578849810131184859674729205058729173270792502638767663048192809434522194737018225369644587150180447065356709781170931762437406116533046733186576058429527459
 . . . . . . . . . . . . . . . . . . . . [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)
							1d1148e6869d45c669fb8eb78dd6b8c5dcdab949
 . . . . . . . . . . . . . . . . [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 (20 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'iws.isuzu.com.pl'
 . . . . . . . . . . . . . . . . [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)
							00f0007700b21e05cc8ba2cd8a204e8766f92bb98a2520676bdafa70e7b249532def8b905e0000016f50a64a2f00000403004830460221008f6028074a6b9ea6ca447904b1e18bb3564deaf1d20cd82b0cacca86707bda0a022100abe9ca734e70d2fb1b829f7f72f94a5c7e198ede83a897f42352b54e238ebfd10075006f5376ac31f03119d89900a45115ff77151c11d902c10029068db2089a37d9130000016f50a64aaf00000403004630440220587c6de01b2bd911bdbe4f015765bbe643b3a027afc5a0c29c93df85f22dc95f0220520718dbab8ccf65ee55437a8416681ffb78c1beaca0fdddf7e2f5df0c85b0d9
 . . . . [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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