www.venditacomputerportatili.com

Issued by Let's Encrypt Authority X3

About this certificate

This digital certificate with serial number 03:34:ba:97:a5:1a:69:f7:fa:0e:a2:80:2e:09:88:f6:50:cd 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=www.venditacomputerportatili.com

Let's Encrypt

Organization: Let's Encrypt
Country: US

This certificate has expire since

Certificate Details

Serial Number (hex): 03:34:ba:97:a5:1a:69:f7:fa:0e:a2:80:2e:09:88:f6:50:cd
Serial Number (int): 279279564667901485690765957630651536920781
Serial Number lenght: 138 bits, 18 octets

SubjectKeyId: ac:52:00:51:c7:e8:39:3d:82:14:0e:b4:b0:fb:76:67:8f:b2:c2:df
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1

Fingerprint (sha1): a7:c4:3a:d5:ec:14:24:f5:cf:83:1c:4f:5e:41:b9:da:61:a7:ac:11
Fingerprint (sha256): 99:04:07:3c:b7:cb:93:ae:63:40:f5:3b:6c:c8:60:76:4e:29:a6:e9:92:52:4a:bc:76:93:c4:5e:82:5f:df:86

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 www.venditacomputerportatili.com

1

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for www.venditacomputerportatili.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

www.venditacomputerportatili.com

Other certificates including the domain name venditacomputerportatili.com

(limited to 100 certificates)

Certificate

The complete raw certificate details for www.venditacomputerportatili.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 279279564667901485690765957630651536920781
 . . . . . . . . [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 2019-07-26 10:49:35 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2019-10-24 10:49:35 +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 'www.venditacomputerportatili.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 703825476191612479666558382744192165644236069744440810274809479413793066843139903591052771918271919922709234471108592205485583543354981897479728806789491793605866464553674442061446763516756405447930683445414846152004201516413508372281526553528643784238646038259018364777012621388958296131945924222255470304705079377549630398351994184998618073383502655367369333231538168463259450455776938348496172618606552572885040186232890829803253754650312886418585917569707453187059462655592327729780823833276970291462871438662938929465488551081150436452213646222391258155470539670126967311789853805489065200815403990021399360984672822601427891880120577180250022933359621319169183504354411202159526554160638277201725275642165447758024908011859194855363505741987261511234346108197407763771837255751368763323604837573479136659513687426024693564790653545228228801315911616383795856749282897094577805077271148054411474504661158327586386060450073214567380767586922156646724542977227103000048435041686697214186780492180029102183280121573767292437777265819552702887038082116883153153044833720578728274113788151915730098686594109036835707880049979832588300401351048979982731059499477968793439884616842407299611216861848618197584487787671191074315399820273
 . . . . . . . . . . . . . . . . . . . . [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)
							ac520051c7e8393d82140eb4b0fb76678fb2c2df
 . . . . . . . . . . . . . . . . [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 (36 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.venditacomputerportatili.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 (243 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (240 bytes)
							00ee007500e2694bae26e8e94009e8861bb63b83d43ee7fe7488fba48f2893019dddf1dbfe0000016c2e1d692b00000403004630440220632adf6962bb4c42a965c52f932b83684b4aac1b8ae8e6ac38ea36457354c92f0220107c67d3b3f884b82551416484bb34073fe238cd077a6fb32e2617da736556d2007500293c519654c83965baaa50fc5807d4b76fbf587a2972dca4c30cf4e54547f4780000016c2e1d697a000004030046304402205696a960268d753c29aeb813bc48a3d8388fb251817819662c42bc3bfb961eb2022050efd901df4a853b9add1bde76f8303ba25f5885e1988d65b7d9365ede4ea5a6
 . . . . [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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