www.mechanicdurham.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:77:8f:29:47:46:ba:db:43:f8:67:cb:8e:c5:df:76:e0:88 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=www.mechanicdurham.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:77:8f:29:47:46:ba:db:43:f8:67:cb:8e:c5:df:76:e0:88
Serial Number (int): 302020753392095742512600486581455864389768
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 74:bb:5b:bf:9a:2d:d6:bf:db:14:cc:cb:81:a5:9b:8b:35:ad:e1:7c
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 90:a5:4d:68:53:97:98:be:51:e6:04:90:7b:3b:20:ea:94:47:60:cb
Fingerprint (sha256): 72:25:f7:db:2e:48:5f:c2:11:9d:f7:44:7e:8d:20:74:e8:02:d1:a1:9a:b0:62:b4:0b:04:1e:a6:18:25:c1:66

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 www.mechanicdurham.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for www.mechanicdurham.com

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

www.mechanicdurham.com

Other certificates including the domain name mechanicdurham.com

(limited to 100 certificates)

Certificate

The complete raw certificate details for www.mechanicdurham.com 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 302020753392095742512600486581455864389768
 . . . . . . . . [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 2020-01-07 18:04:21 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-04-06 18:04:21 +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 'www.mechanicdurham.com'
 . . . . . . . . [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 619513694538327128510574500056460748845941648399084855436119412476548251066383204752303527507884453180416868093650823116891740795419139053117307186780074732765363588011156177036945680960851364205251729055559986927225327437689369038739881504747192620559663491991802633270103081742364818555193743716626336344187157386351955204877167247541921293991475324457780139255395157495332673106934605545853729257113843420675800281213753710796359388548697636649586160973560393135345967731558066925523600060920692874224338266517655904808641890149808010490058358110114019861099732919696644898544680669612694976791320040455171379281893751035685383735056090593804724525279735688560318608283452637556240704464196720556727667930570480460473391007759921280891045255053311291376401242371211970493500203339007440947426237393562523735503211499118606831145540303006986344176176389503617265552340760137468144397505806290787706947689322599182775520937775323847805599431618975198678364324636033741178422392178855712936487156788310064493296944779784137185402227021755749196002682867768114853258012452582186537284901047531667858079523486048156860103421723147234623789650516125716114754210024189801880517639051771728806965922311484917035991803040903857861294803291
 . . . . . . . . . . . . . . . . . . . . [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)
							74bb5bbf9a2dd6bfdb14cccb81a59b8b35ade17c
 . . . . . . . . . . . . . . . . [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 (26 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.mechanicdurham.com'
 . . . . . . . . . . . . . . . . [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)
							00ef007500f095a459f200d18240102d2f93888ead4bfe1d47e399e1d034a6b0a8aa8eb2730000016f8164c1ea000004030046304402201346aa192a73194b68b39e15ec709ca580c0b519bdadf0f8d3146b9f88e7e40e02205e8a0f997bc653fb9cf873583bff0b8e3dc47f1ff2975ef4033bd1fe9ac914c100760007b75c1be57d68fff1b0c61d2315c7bae6577c5794b76aeebc613a1a69d3a21c0000016f8164c2310000040300473045022051321f866cabe5101a88af0ffbd5ba1d05e46aed25cd25b41a221beacbd39cc6022100ae423b4c111c63090ea7d228d464f0c8236756c4c1cc272872d22ba58c26535f
 . . . . [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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