openms.co

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 04:4b:ac:cc:8e:23:8a:17:0d:e3:c1:cf:bc:a1:a9:7f:2f:da 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=openms.co

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 04:4b:ac:cc:8e:23:8a:17:0d:e3:c1:cf:bc:a1:a9:7f:2f:da
Serial Number (int): 374200010572863404190002158145780878094298
Serial Number lenght: 139 bits, 18 octets

SubjectKeyId: d3:7a:da:33:f9:64:56:5b:82:0d:33:04:7a:03:6c:94:65:ff:65:0e
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 7e:c1:21:2b:83:05:e7:20:11:51:26:2a:73:f8:f1:95:62:c2:92:64
Fingerprint (sha256): 11:9b:c6:fa:e4:b4:d6:f5:ef:60:13:ad:3b:4b:28:f5:75:a9:b4:3c:7d:4d:70:f4:fd:10:63:67:2c:fb:39:da

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 openms.co

2

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for openms.co

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

openms.co
www.openms.co

Other certificates including the domain name openms.co

(limited to 100 certificates)

Certificate

The complete raw certificate details for openms.co 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 374200010572863404190002158145780878094298
 . . . . . . . . [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 2019-11-08 06:42:10 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-02-06 06:42:10 +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 'openms.co'
 . . . . . . . . [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 853067507798263179185853656293633226998057553469309708758842671985873238957976482628525541609221199491677673796255403607606842680793616048384803972849053977810633335702134766276846701318398586610679866546628312537533465803061826952323509747246983598803270830287203182979047825701482155779621701036517238875059557952300203284499788359364231016145619307456383524030560344791180505127363028461993278543842264474869429438636471256922540851746760839769003806778885572429359125927613800203035398061104466571226618925584292549772771034238996974187684640079842749620612238430652306190850520110246019694149774632265833626816066534534179929741231586657025095589054639467034469837628731863239402958985614885483841117621949271828736328901828880988569356503844294276304248247303198271534816604241433257910756646246980383309162993105232359875168802156476864322611381291687869602255689573979655477885011067849414012819138775622782034100215012407995279453256314869832861727043314277822922075437678194418639331793110597806615426839453468485756165525657268792637995193339421384053569362387108745046414198967566909204524199049472343014443972566130757250960457414995150816585401619680814518410730694188178868262000500027255683958709845112776042902054553
 . . . . . . . . . . . . . . . . . . . . [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)
							d37ada33f964565b820d33047a036c9465ff650e
 . . . . . . . . . . . . . . . . [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 'openms.co'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.openms.co'
 . . . . . . . . . . . . . . . . [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)
							00ef007600f095a459f200d18240102d2f93888ead4bfe1d47e399e1d034a6b0a8aa8eb2730000016e49f6a0b9000004030047304502206aa61064d2c4c7a46aee6198160c5418bb087cd435d8d5434c034fa4c43c314d0221009f6dc25ac38a2b4d7bce35355ae586f54547efab5216770f628c7175a5d44c0500750007b75c1be57d68fff1b0c61d2315c7bae6577c5794b76aeebc613a1a69d3a21c0000016e49f6a0e9000004030046304402206b670160da985eb94e4be976e9959e8927a6157b714dbae2c85b6db25519a20a02201dc71b7fc009e684ef3058bad973b8a7fe502a07b256c2bd7287fd3350432c97
 . . . . [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)
		0020aca42d589daeaf8ea2419e35ab7eeba5fbfdf26a0b993e873b02b472edaf98eb092d5bcd838f8246bd6c6f173ba1bd1094c57a496f5e7b4b265673900e45dcf5733efd1262980f7da70634c5837a96527d5a14f85a47159e33197eb31a3c364d3f0d07ffbcfd2f371360ed1436ceecdb7e36cae9d8a2623e178a50500f689fead42d4e746e352041dd7cd98b87b163ef173bccb9f4c7de42e713e0209337221250bfced62f47fd5434b4d607f5e79fe6dd67df6a35749821c62a78b42298b6a56fbe035d10d88e3b732bd3e2511fa86b9b9018de81c844675086a3fec19de200f38f3927d7532ebacf7a92751add52c1dc2c355206bd0c222ff2d8f6f6b9ac