marcastudio.com

Issued by R3

About this certificate

This digital certificate with serial number 03:e5:e8:ac:e8:3d:a9:3f:55:04:22:a4:39:9d:f7:2a:3e:2a 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=marcastudio.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:e5:e8:ac:e8:3d:a9:3f:55:04:22:a4:39:9d:f7:2a:3e:2a
Serial Number (int): 339570798500661742036871814283706317291050
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: 3f:bb:08:c1:64:3c:4f:0a:ca:f1:b9:a4:64:07:c8:57:1c:91:0c:e3
AuthorityKeyId: 14:2e:b3:17:b7:58:56:cb:ae:50:09:40:e6:1f:af:9d:8b:14:c2:c6

Fingerprint (sha1): 2d:7c:db:a7:d6:0b:07:9e:40:c0:40:e1:ca:db:cb:96:e6:bc:0b:7b
Fingerprint (sha256): 3d:96:2e:3d:c3:4b:e2:83:ab:0b:5b:d2:cc:d8:d1:be:b0:8f:de:46:14:21:ed:85:7c:19:f5:e1:3b:fb:55:dc

Issuing Certificate URL: http://r3.i.lencr.org/

Revocation information

OCSP Server: http://r3.o.lencr.org

Check the revocation status for certificate marcastudio.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for marcastudio.com

Public Key Algorithm

RSA

Key Size

2048

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

marcastudio.com

Other certificates including the domain name marcastudio.com

(limited to 100 certificates)
web01.marcastudio.com
marcastudio.com
66ed3gs.com
compaddict.com
distrimedicperija.com
www.svep.com
mapadorole.com.br
inkwire.xyz
www.federicofumo.com
genes.davidmdabney.com
melinawedsjonathan.com
dev.scorecard.ghandicap.com
bupples.com
www.dresez.com
www.federicofumo.com
www.aproject.ml
bcom.knowledgebay.net
rmgatorclub.com
www.outgoing.app
marcastudio.com
marcastudio.com
heathjhmoore.com
link.iotassistant.app
gran-canaria-kleinanzeigen.com
www.fasterhousekeeping.com
apps.marcastudio.com
marcastudio.com
milson.marcastudio.com
marcastudio.com
sdk.customfit.ai
lo-fi-stadium.orangelv.com
galitoz.mybusinesscard.co.il
sic.cmgraca.ce.gov.br
myvitalogy.net
drburcudogan.com
www.ibdpg.tw
www.govulu.com
link.iotassistant.app
happybirthdaysister.ml
covidhk.feli.page
audits-dev1.nucor.report
app.developertoolkit.io
www.amsoironworks.com
bloodyfingers-typing-game.com
www.morgannels.org
epacific-admin.toan.io
audits-dev1.nucor.report
tms.waylar.net
www.abbon.co.th
pos.behtar.co
stg.burnian.com
millson.marcastudio.com
gamertrainer.co
www.handy.com.ec
tuconcierto.shop
amistad.lopezlopez.club
millson2.marcastudio.com
tms.waylar.net
salepeli.com
www.bitontree.com
www.homebuyers.bid
app.shopovant.in
www.cashierr.nl
charliewelsh.com
www.bestbuydelivers.com
web01.marcastudio.com
www.dtea.xyz
twaddle.io
web01.marcastudio.com
blog.andiflorea.dev
www.objectivegoals.com
workzilla.co
www.findmaids.co.uk
randart.xyz
symptomcompanion.com
apps.marcastudio.com
atomicbeautysalon.com
ws2.malaysiakini.com
marcastudio.com
www.aisw.tv
www.tappsports.com
apps.marcastudio.com
p4rty.io
chikchengyao.cf
dev.enterprise.vette.io
app.brewce.chat
factura.prendamas.com.bo
closedbrackets.com
app.favo.jp
gundo.app
axismed-axismed.portal.carenet.com.br
autopark.codesouls.com
www.fregomotor.com
blog.andiflorea.dev
www.algoforms.com
platform.marcastudio.com
japasupply.com
royalsportbank.com.br
pastiche.design
marcastudio.com

Certificate

The complete raw certificate details for marcastudio.com in PEM and ASN.1 format.

Certificate (PEM)

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAmp5NWQqJuIFm/v1IXJFz
0Uy8jWxiIBXqnZgm77fNCl52y7DHebhKNTAZIby0bTTGB2uVkfh+xJTSNef9Hy53
6r4N0/6VV4vjhNj9cc+Gr2M+iwaREaGMLc16aActGD3d496PgdoSkbScRcr/tSAh
LQ3ChuGDIbusYvsG+G5h5bwT/QsvXapXLbq051RH/XiZ6mdd5kUryxUVUxf9vYY2
3roKHVOb936RXPEa1I06y4q4cYo92KeOROwowqACPJc4rEQHPYLeaYMlNeRu0B1n
xhNSc1bevMyFfxcyaj+YFkLaYLfCi1qE1tR49u9CYWBtfDiy7QVefAga0fFmLJVB
CQIDAQAB
-----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 339570798500661742036871814283706317291050
 . . . . . . . . [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 'R3'
 . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2023-01-20 01:52:02 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2023-04-20 01:52:01 +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 'marcastudio.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 (2160 bits)
 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . [c:0|t:2|false] INTEGER 19518760659362016134145263115211358476165379809711304758183194743925015494213415648052361979125646661197016747385957466839334508458897233789755165632863779765603347734614118249254950775695484101497952466587619651060396568504377122706228569586268932732247135423446503200902508835675946982585426538815370780826085940664788114644967381526142268295055135738455703187209916495164824807557651775282165541112878624837677354933139001440147359252743134948806626864469872191396735988047255447416381001545629382175956628289801472595715252751463687477908525126374569097415123622213885251883652059848196339148878660368923670954249
 . . . . . . . . . . . . . . . . . . . . [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)
							3fbb08c1643c4f0acaf1b9a46407c8571c910ce3
 . . . . . . . . . . . . . . . . [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 142eb317b75856cbae500940e61faf9d8b14c2c6
 . . . . . . . . . . . . . . . . [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 (73 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://r3.o.lencr.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://r3.i.lencr.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 (19 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'marcastudio.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)
							00f0007700b73efb24df9c4dba75f239c5ba58f46c5dfc42cf7a9f35c49e1d098125edb49900000185cd171edf00000403004830460221008d2ca11bb9de980dfc53c9e5bb5c191b1bb073845abb472352b4914c8973541a022100d750d3a76c940fc37135d58390787f19b8c33250be2e45e21e262748a40b4284007500adf7befa7cff10c88b9d3d9c1e3e186ab467295dcfb10c24ca858634ebdc828a00000185cd171f18000004030046304402205cbfc6a1f04283bcf04924d9636623f945c942028c84d14178433becffc7ede90220377f2516d600364735cca36add60ebb11f0f99fe17df6adcb9c6067e2c74d2a0
 . . . . [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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