malu.eu

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:53:65:78:7c:bf:1d:6c:27:ec:00:31:1a:e9:59:eb:19:47 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=malu.eu

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:53:65:78:7c:bf:1d:6c:27:ec:00:31:1a:e9:59:eb:19:47
Serial Number (int): 289715171883076408800641195789027524680007
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: b3:88:32:46:ac:a4:e9:2d:a1:6f:f3:30:52:dc:02:88:91:b3:1e:75
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): 1a:84:23:f6:8a:8d:78:97:26:0d:85:25:82:29:99:bb:12:be:8f:92
Fingerprint (sha256): f5:0e:0a:94:2e:78:2c:66:06:54:fa:3b:0b:d9:71:38:8f:9d:9f:29:74:09:3b:d5:3b:f6:e5:e0:c4:a9:93:42

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 malu.eu

2

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for malu.eu

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

malu.eu
www.malu.eu

Other certificates including the domain name malu.eu

(limited to 100 certificates)

Certificate

The complete raw certificate details for malu.eu 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 289715171883076408800641195789027524680007
 . . . . . . . . [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 2019-04-30 14:09:21 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-07-29 14:09:21 +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 'malu.eu'
 . . . . . . . . [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 770839303487720981936498079817202253337762504016075712472554175878687614789212843955983519158065691712390902705849324931575710621559032832907208361749944091832826536773988427629775673834518168506741425871483330564555059358650312520280390170906961783095936857960870636704004722782246609672662764698583492415671831530226863463739961494692824247264774700573759025583176967358351397315485706436604447692566889220085423173553606555798885083169524004507905329556554098272520735723075837541427439997641666466800524774789275034948567582023057063547247927265439429355406910928822700984370586355877738260446796338775192315626977567582321265874219209150424138237102605955271813506056703736551501803044328143406761217633048421438651360124829656765189699277431970075260724287615694933388228119994104947366481801442613788041471546570887670859984053074671410008301641382797711383700593172056161959572153937062297502021690525650972573538334760957684580185799325905068061742288129355028445484445472311644592874280567307044405732054035142549337232865345201914332972860665199482275910799363597038045547467806355700017479029669994270328410604040162118319035309178866155093955395040429221852019318481732090551370906691652142999635136522288808943154778567
 . . . . . . . . . . . . . . . . . . . . [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)
							b3883246aca4e92da16ff33052dc028891b31e75
 . . . . . . . . . . . . . . . . [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 (24 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'malu.eu'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.malu.eu'
 . . . . . . . . . . . . . . . . [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)
							00f1007700293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f4780000016a6ecb0b070000040300483046022100f8b61b2afbc3c1d42fa34f5255986c7bd73d9bf45d4cc8fd212b1a664d51f307022100b1a92ae8e8e16ac1b5022db1d5d6d133a5136d3f899248ceaf15a290627e2624007600e2694bae26e8e94009e8861bb63b83d43ee7fe7488fba48f2893019dddf1dbfe0000016a6ecb0d24000004030047304502207295acc25491849d0c2e6438ae9a79b0fa7f20b811d99b574987ede3d850eeb40221009a0df68e06d894cb62c5d0e3247861fd069ef03696367d6e9fea5c9ac4f6e617
 . . . . [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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