oleum.org

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:b5:42:e9:cc:2e:b9:15:b9:39:01:28:a1:26:19:a5:b3:73 was issued on by Let's Encrypt.

With 2 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=oleum.org

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:b5:42:e9:cc:2e:b9:15:b9:39:01:28:a1:26:19:a5:b3:73
Serial Number (int): 323016909202173780498737035320704207532915
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 93:3d:8e:b4:6c:57:a6:5a:0d:01:15:51:fc:d3:3f:26:e4:77:05:6b
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 5a:21:07:e1:82:94:74:e8:28:85:3b:34:22:7b:17:30:6d:34:5b:cf
Fingerprint (sha256): 5f:a6:c0:1b:ad:13:35:d2:51:42:5a:da:7b:99:f6:12:f6:67:b3:08:fd:a3:28:bc:e5:6f:26:98:d6:7b:50:c6

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 oleum.org

2

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for oleum.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

oleum.org
www.oleum.org

Other certificates including the domain name oleum.org

(limited to 100 certificates)

Certificate

The complete raw certificate details for oleum.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 323016909202173780498737035320704207532915
 . . . . . . . . [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 2020-03-19 13:03:55 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-06-17 13:03:55 +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 'oleum.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 851640861751769681392973142973294882689327499593284959903772440614381511932442361797855343879860925627130017227036183849218809232353961052151497698688687332068125659945772875707944801836448349864364559605077180092829124646060761419785574652584850324290288297330913466575500524829377605258914037458418954526697346036358896367285071781430466810842312001199021433728623881177800858347351168615467913274709734957674566324922531340337767990228530133503216587468425438553801147021723581687637232361434000031248643506401922767604620569427521144929611039363924851279859486430528193114723977692479251013888783108042155241235414410862481601954492281603400982456385997082533750915762478493587593370878477460135405370495106076102862735707015084521017955253905698674942264029925888559145214796512978322834564651403254301053383721784097674871718256057419210957610045567296703547536142705167355275729752684020032735025862320376541630527103233913798372538582989927339266816227073245512491294522982687465995524769629677411690988907558868256310204013998776831237222148644451311540914397958876800524354560826180824691964136897458692620639639411660164830382586638098066706399697521752572212588878205528236002913534354747985277048606764682975876260611633
 . . . . . . . . . . . . . . . . . . . . [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)
							933d8eb46c57a65a0d011551fcd33f26e477056b
 . . . . . . . . . . . . . . . . [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 'oleum.org'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.oleum.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)
							00ef007500f095a459f200d18240102d2f93888ead4bfe1d47e399e1d034a6b0a8aa8eb27300000170f31b9481000004030046304402201e4d0fdb326cd436ab82f89e938ef1c7d1a7f2ef7962faa22fe903c5fb1caa8f02203b4936e6973441e9deb3471ed7cd20a3cdd6d13b996c673154ef4c2eb02569b2007600b21e05cc8ba2cd8a204e8766f92bb98a2520676bdafa70e7b249532def8b905e00000170f31b94e40000040300473045022100c7dd12a383be25bef51391ca1ca998b4c4d523db2c65b86e247debfe53dbbe21022051ab19675dee823ca4b4c9ce0e317f0671eac49659b0488e2c42932cda4d3534
 . . . . [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)
		0010f568420254e72d57026d0bab0e9838a9967d87e601b065233c3432336bf679e8f7e95b6b1e2426bf1f84c89142ff9feb0302a2eb60c3ee32c32eefd75cb0e6b740937c8f7f991fc797e8a30651f71b2e13b4c5c667485f54c0b8a2cca42f6d33ec00039551c1aeaf5e9d878770fc620a68f1458a6a4e4de90ef7ed28d250fff36e3129381e76160bfdffd440cdbe2d2c1aa5445c6cbbb8c44ca7d44357357fb481e9a3151d0341a4833a29a63373cc084cc647d15ba4da06e5e48e59a0ed81b0605613fe2761c867df4b174a6731ae5adfe8bdfbe583c40d2670da7107a20fc0ec924e1b5ce185bc1bf5bba1ed3bb7122d3af00c1bd0dc857fd4b9c62e06d2