www.ultradux.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:59:73:2c:f2:35:b6:32:57:60:0a:ed:cd:c4:c7:85:14:6d 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.ultradux.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:59:73:2c:f2:35:b6:32:57:60:0a:ed:cd:c4:c7:85:14:6d
Serial Number (int): 291775083044419907873567908696945523496045
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 05:65:2a:f7:34:58:0f:f3:1e:9e:48:a1:37:cc:0f:ee:fc:a8:ac:55
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 88:a9:3c:96:d5:36:0d:6a:e7:4f:eb:49:80:0b:90:bc:1c:ba:f2:d5
Fingerprint (sha256): 9b:da:c0:b9:9e:b7:98:9a:f4:a8:90:22:70:02:26:d8:ea:1c:70:bb:ee:9c:d4:ab:49:2d:c3:bc:b9:e8:1c:b4

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.ultradux.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for www.ultradux.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.ultradux.com

Other certificates including the domain name ultradux.com

(limited to 100 certificates)

Certificate

The complete raw certificate details for www.ultradux.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 291775083044419907873567908696945523496045
 . . . . . . . . [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 2019-12-16 22:09:08 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-03-15 22:09:08 +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.ultradux.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 754647841808830939383864829993313549245200045071136735443481057486273953373502069212790176578435432687077655253002398045878342583604919354578321150097764667246178008020590832363849967007345076855811683516262956203530000721746629539950508329420428309796370714686413344579792534281913739147303424513929093259814474773863689428015022492359770318797522761205947283791999339995359360790175808725781786368635814541104242354111368701892491837501021438954093494829811606934832539950816625917654449283866623855786238111895785220853456899801107089297427937612286833110445323618672857192974400281245306393659922191398961912530687203613338205253502998310405697618186963741273610756138630972543163741027352674474823011077016161014154009073027963038071830213793090244558497639179870645558480493418904373933967998551751734532024168531717037831650780537500123530067128768769799269314880458612574720533544615662627640878522599945207226052158027028196701035444344486839816924649852792694361484677885417105024563858205414747788312222221532731723923404390586928050973192816247242755570814517354783068086309304480769131864293684961294744975868106849916440234760014154508960615413397797487581771871942508686263622642633717594464754912363756319049304777461
 . . . . . . . . . . . . . . . . . . . . [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)
							05652af734580ff31e9e48a137cc0feefca8ac55
 . . . . . . . . . . . . . . . . [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 'www.ultradux.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 (246 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (243 bytes)
							00f1007600f095a459f200d18240102d2f93888ead4bfe1d47e399e1d034a6b0a8aa8eb2730000016f10f8f61700000403004730450220762062dd6d3c69118b34c0eefd2bb791a8bb96085dca5ffb50c8e3268b99e6ee022100abb10be37e12aa897554aae41ec3cf48b26afe8484f8389b08a3b26b0da9ec3e007700b21e05cc8ba2cd8a204e8766f92bb98a2520676bdafa70e7b249532def8b905e0000016f10f8f60a0000040300483046022100e7e79de53195f532d98a67dee65e9b3dccadc1a11a861af90b57cf0c050c15d5022100e2fd6792f46048c48af5425f6dba80d232ad7c4b928f8cbd8bc4cb719e526c23
 . . . . [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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