*.orangii.cn

Issued by Sectigo RSA Domain Validation Secure Server CA

About this certificate

This digital certificate with serial number 8e:59:ad:39:a4:ee:ee:d1:3f:00:a2:69:55:93:50:e8 was issued on by Sectigo Limited.

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=*.orangii.cn

Sectigo Limited

Organization: Sectigo Limited
State / Province: Greater Manchester
Locality: Salford
Country: GB

This certificate has expire since

Certificate Details

Serial Number (hex): 8e:59:ad:39:a4:ee:ee:d1:3f:00:a2:69:55:93:50:e8
Serial Number (int): 189216003245778742402231516832568922344
Serial Number lenght: 128 bits, 16 octets

SubjectKeyId: d6:f8:30:f7:80:9c:d2:10:8c:69:f1:f2:31:82:54:74:b4:6e:94:14
AuthorityKeyId: 8d:8c:5e:c4:54:ad:8a:e1:77:e9:9b:f9:9b:05:e1:b8:01:8d:61:e1

Fingerprint (sha1): 6d:54:0f:0f:60:35:0e:05:61:80:a7:b4:2e:cc:ca:4a:08:09:95:c4
Fingerprint (sha256): 81:d6:39:a3:1d:3c:fd:a3:79:4b:33:c9:63:59:d2:9d:49:b8:ce:bf:77:29:98:44:95:04:9c:6f:fe:bc:99:bb

Issuing Certificate URL: http://crt.sectigo.com/SectigoRSADomainValidationSecureServerCA.crt

Revocation information

OCSP Server: http://ocsp.sectigo.com

Check the revocation status for certificate *.orangii.cn

2

DNS Names

0

Email Addresses

0

IP Addresses

Advanced Certificate Properties

Tehnical certificate details for *.orangii.cn

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

*.orangii.cn
orangii.cn

Other certificates including the domain name orangii.cn

(limited to 100 certificates)

Certificate

The complete raw certificate details for *.orangii.cn in PEM and ASN.1 format.

Certificate (PEM)

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

Public Key (PEM)

-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAwexcb6/QQ49M4WExHT/x
ku84BmS/5xdOX0w1jHx0zetbcg6wO30S7vjCkq/wG9PL6oB/6HznZqu2zQBwzL7I
Q9E69iCT6f7k1xovZpWTxcn225hAEK8r8nNhABX+zgPMppmRVpR4vLU/mTo3tJQL
SzKu5R9K0ZUnV7qXUEf+ozoUQiZzoIHMpV9azd2loTBXo3iymuE6+TtqNlNZm+39
dLHYiSyLatJzyGNeomb9LySyFL2Y/ETD3FjkQs8CgvdnAjukqWbvbn0CcJvUd6VB
WMo8jtFnzX4n/PPWB7pacBUyrWONjjuWi99Rp7vJQVCsWuDSKaNtLKeYM6jayhNU
mQIDAQAB
-----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 189216003245778742402231516832568922344
 . . . . . . . . [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 'GB'
 . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF 
 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.8 (stateOrProvinceName)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Greater Manchester'
 . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF 
 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.7 (localityName)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Salford'
 . . . . . . . . . . . . [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 'Sectigo Limited'
 . . . . . . . . . . . . [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 'Sectigo RSA Domain Validation Secure Server CA'
 . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2022-12-11 00:00:00 +0000 UTC
 . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2023-06-09 23:59:59 +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:12|false] UTF8String '*.orangii.cn'
 . . . . . . . . [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 24480546850632023134655053380999868454672519951056016372925678004037730182295499873151196865575588803587711945301652565027153452400895489186814396944821105300362781723945136972303146605729876049885099985212514757078730728718746689143063730425856560303566900463769267060031350099279201459267947493332253121019608758575426339598109057405223962238307717489621341960257913992255536752273626170207537604998718612578862994531314509701298098730005721178172901512551686207544292500423342581550765911203367964641906092643424403929796857014866182009021471875338368593667869520464601557219765688573103940781726050413880020259993
 . . . . . . . . . . . . . . . . . . . . [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 2.5.29.35 (authorityKeyIdentifier)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (24 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|false] OtherName 8d8c5ec454ad8ae177e99bf99b05e1b8018d61e1
 . . . . . . . . . . . . . . . . [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)
							d6f830f7809cd2108c69f1f231825474b46e9414
 . . . . . . . . . . . . . . . . [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 2.5.29.19 (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 2.5.29.37 (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 2.5.29.32 (certificatePolicies)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (66 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.4.1.6449.1.2.2.7
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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 'https://sectigo.com/CPS'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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 1.3.6.1.5.5.7.1.1 (authorityInfoAccess)
 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (120 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF 
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.48.2 (caIssuers)
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:6|false] IA5String 'http://crt.sectigo.com/SectigoRSADomainValidationSecureServerCA.crt'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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.sectigo.com'
 . . . . . . . . . . . . . . . . [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 (366 bytes)
 . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (362 bytes)
							0168007600adf7befa7cff10c88b9d3d9c1e3e186ab467295dcfb10c24ca858634ebdc828a00000184ffefdf9800000403004730450220382a138b9220c66382766c023091a7d8085709f1e7d364bb364901988efa5c8f022100908746defbd4d518f0824398b8212cfe04459b4dd3953e9a9b492a7c3a73b803007600b73efb24df9c4dba75f239c5ba58f46c5dfc42cf7a9f35c49e1d098125edb49900000184ffefdf770000040300473045022032b4b139fd858cc61919fa0db6f883ef28950433ec16b8fcc691348dd3a17da0022100fcc98f891f0b7759a3ee7794000b44fc5316bbbec22c922d45eb2e2f29bef733007600e83ed0da3ef5063532e75728bc896bc903d3cbd1116beceb69e1777d6d06bd6e00000184ffefdf7a00000403004730450220347ea088d94b06880d9aee7a1e48ebc43b727347dbd15c1e343ac99261bc9b12022100fb6a5fae133c532c38494a2af7d19c2e331ddece60fbad3e018ef043b1d44c02
 . . . . . . . . . . . . . . . . [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 '*.orangii.cn'
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'orangii.cn'
 . . . . [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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