foro.make-a-tronik.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:f9:aa:65:f7:58:8d:03:5b:a7:b6:30:c9:de:2c:39:43:86 was issued on by Let's Encrypt.

With 8 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=foro.make-a-tronik.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:f9:aa:65:f7:58:8d:03:5b:a7:b6:30:c9:de:2c:39:43:86
Serial Number (int): 346293665356631456907445313876582890816390
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: c0:9f:ec:01:0f:64:60:a1:82:49:9e:bf:77:df:c2:91:da:e7:02:6d
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 48:c4:12:56:19:99:26:34:1d:2a:7b:98:bc:9a:db:c6:a1:f5:59:ac
Fingerprint (sha256): ca:13:4e:19:8e:5d:a1:81:df:f8:9a:cd:57:34:6d:c8:af:7c:97:8a:e1:fd:87:51:6f:f6:c6:50:54:89:e4:a7

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 foro.make-a-tronik.com

8

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for foro.make-a-tronik.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

blog.make-a-tronik.com
foro.make-a-tronik.com
fundacionayudarporayudar.make-a-tronik.com
tienda.make-a-tronik.com
www.blog.make-a-tronik.com
www.foro.make-a-tronik.com
www.fundacionayudarporayudar.make-a-tronik.com
www.tienda.make-a-tronik.com

Other certificates including the domain name make-a-tronik.com

(limited to 100 certificates)

Certificate

The complete raw certificate details for foro.make-a-tronik.com in PEM and ASN.1 format.

Certificate (PEM)

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

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA6uETC6aksKOH3zVnOwW2
sgjND4m2183vCT5wZCeSGb29PG1Ds63nDISsP8TMEMmvqecVWCBy+mA+6bJXEuSr
MNKcRo59fSRAXW8K2CSWcD6W+fTF4imw+rm1oamBeKANfaMTox50EM0CiGKbZ7On
5lI5GQecqfN0u8kAp2bArEWEfzkStXbhxIPGaj1HPz8sm7i3/1a13wCgphaK30k2
pZzZEIx1q/IiYPFYUDq4SzRfvh1GxzGbkoAgNhtNf8kein8ZoLnFgcga3mE5rGVH
QL1qI1CAebJDKPGweGbOCA6ua+a0smWfmf6rV9qQBfZQr++cg6+zdoC6nlmfBAXy
vQIDAQAB
-----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 346293665356631456907445313876582890816390
 . . . . . . . . [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 2019-02-14 07:28:19 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-05-15 07:28:19 +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 'foro.make-a-tronik.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 29650751683577754516406902513102548334987741025783598750147538910458227836062565369110156992768743591680269173249477843376304729362187110157074183716534605003755248944004774266068192833134004439317109358236041574833091558137325836434481402998637939823400289391464338690879416910476761892347081516157140299127874428609849057319295503481560952628823704825041881798424228878682241414978955538581874318307710839848344445640393284243265297092282929534857145225926728851014031874460250505495654577259150535948616971613483597889102909108835804741838549272807555378922153687411854392262291460513640618489304884562417749979837
 . . . . . . . . . . . . . . . . . . . . [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)
							c09fec010f6460a182499ebf77dfc291dae7026d
 . . . . . . . . . . . . . . . . [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 (255 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'blog.make-a-tronik.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'foro.make-a-tronik.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'fundacionayudarporayudar.make-a-tronik.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'tienda.make-a-tronik.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.blog.make-a-tronik.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.foro.make-a-tronik.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.fundacionayudarporayudar.make-a-tronik.com'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.tienda.make-a-tronik.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)
							00f0007600747eda8331ad331091219cce254f4270c2bffd5e422008c6373579e6107bcc5600000168eb1eef7b0000040300473045022100aac476d247f4fdf15e5690f498339258bafd4b2b033838cfc4859e7df9299f3c02200318630b197cbfb8a751136301bfc91952bdb6a5570e4f355cb4003ccb5c997d00760063f2dbcde83bcc2ccf0b728427576b33a48d61778fbd75a638b1c768544bd88d00000168eb1eef54000004030047304502210093b3db5b376c31fef4d2d72222a6e85589dcc68ebdbf0044c324dc5063e1118902202094b75b8f0482f4857724b05c28c413c4cfb0fe28ec76451cb48fe9bc75705e
 . . . . [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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