twiser.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:50:ee:22:bb:10:0e:8d:ec:e0:02:5b:62:e3:73:b2:10:04 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=twiser.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:50:ee:22:bb:10:0e:8d:ec:e0:02:5b:62:e3:73:b2:10:04
Serial Number (int): 288875983744128568029211536860557037670404
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 50:f5:0e:99:6b:2f:54:84:f8:ef:21:68:20:24:a3:e2:0b:bc:6c:af
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 87:4b:a3:4b:f5:07:70:b1:d7:3e:d7:e9:ed:37:ec:c7:24:59:2d:d0
Fingerprint (sha256): 86:d7:15:11:37:bc:11:ee:cd:3a:45:00:c9:c3:4c:1a:7f:c0:2f:8b:9d:50:5c:9d:ba:92:40:78:5b:7a:17:2a

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 twiser.com

2

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for twiser.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

twiser.com
www.twiser.com

Other certificates including the domain name twiser.com

(limited to 100 certificates)

Certificate

The complete raw certificate details for twiser.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 288875983744128568029211536860557037670404
 . . . . . . . . [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 2019-07-02 19:16:13 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-09-30 19:16:13 +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 'twiser.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 1002742457453918306162747266381767739690542291892639258660550487554307485465966291518548750412331430552839808680532715383590338612486157703432205784753570698619854834273550316244008763570706936958638819045836674516295825339432448317305511131833178132849635582137290342501550478593605278151392104292425883344505063989216007994105357454465621533979981426939436549711385470052118849184396864951990604259232354844793896610742744022841451253656338190111288798278982332058264224798205497878213643713995465615264107239679989141152543141426550839353893365278105909381760349983277371930312050568331339114367452961269644430111550969666691181389404903734943920855493640501776474323875265827283933405752793922936376263197935922572832985154457279449011261200015717629483129137527066410773711835235312059029688254539023347841900732742959044269203135640067524883188579356117122097916002146302449336466719977297278263022253237909975848846906006020085127761536931698157393441414917489384358740933610350456001461452656446972850520443570998628012282091887180690131665412091034288858190083995794918869530545462475579202973263265206763459310167384781289806890591087851393339853425682676152171891644300868327112899555273818892434283203942594379937235306381
 . . . . . . . . . . . . . . . . . . . . [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)
							50f50e996b2f5484f8ef21682024a3e20bbc6caf
 . . . . . . . . . . . . . . . . [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 (30 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'twiser.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.twiser.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 (245 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (242 bytes)
							00f0007600747eda8331ad331091219cce254f4270c2bffd5e422008c6373579e6107bcc560000016bb454a1b80000040300473045022100f187ce086274a599c93a9dfe52ab77020633b03904a22136069db45fbd22228402200d04d47ead3ecee790453c2947b860fe10e0844f6a0c428cef426a178fc2a76d00760063f2dbcde83bcc2ccf0b728427576b33a48d61778fbd75a638b1c768544bd88d0000016bb454a1ac000004030047304502203c07701bac1ac353ab138956eebb95d1aa9ae4e5683bf2cbb6889974fba1c519022100f5b26c39715421c60c2fbb2ae40e241f70695916956816987aaa4567974d7331
 . . . . [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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