filr.psc.ac.uk

Issued by TERENA SSL CA 2

About this certificate


This digital certificate with serial number 46:b4:9a:fa:c8:c9:c4:1a:4b:8e:8a:95:ba:b1:ee:0e was issued on by TERENA .

This certificate is currently not expired, we haven't checked the revocation status of this certificate but you can do this simply on revocationcheck.com.

Peter Symonds College

Organization: Peter Symonds College
Organization unit: IT Services
Address: Owens Road
Postal code: SO22 6RX
State / Province: Hampshire
Locality: WINCHESTER
Country: GB

TERENA

Organization: TERENA
Postal code: SO22 6RX
State / Province: Hampshire
Locality: WINCHESTER
Country: GB

Time untill certificate expires

This certificate will expire on

Certificate Details

Serial Number (hex): 46:b4:9a:fa:c8:c9:c4:1a:4b:8e:8a:95:ba:b1:ee:0e
Serial Number (int): 93983716499740893122633653772776238606
Serial Number lenght: 127 bits, 16 octets

SubjectKeyId: fa:55:f3:1d:88:4e:a7:ef:54:37:fa:43:45:78:70:fa:3d:ff:dd:e9
AuthorityKeyId: 5b:d0:8a:1c:9a:32:5b:e0:b5:dd:96:54:1b:e1:86:28:b0:fd:b6:bd

Fingerprint (sha1): b1:b0:15:b4:b2:cf:dc:15:28:af:77:b0:ad:38:b7:92:24:1a:d7:13
Fingerprint (sha256): 96:21:f6:ba:99:ac:ab:c8:2f:b5:5e:e3:86:57:19:ed:95:ea:fe:37:45:3f:fa:73:93:e3:8d:12:33:e7:56:87

Issuing Certificate URL: http://crt.usertrust.com/TERENASSLCA2.crt

Revocation information

OCSP Server: http://ocsp.usertrust.com
CRL Distribution Point: http://crl.usertrust.com/TERENASSLCA2.crl

Check the revocation status for the current certificate on filr.psc.ac.uk
1
DNS Names
0
Email Addresses
0
IP Addresses

Advanced Certificate Properties

Technical details about this certificate


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

This certificate doesn't contain any other subject alternative names besides the common name of the subject: filr.psc.ac.uk

Certificate

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

Certificate (PEM)

-----BEGIN CERTIFICATE----- MIIFCDCCA/CgAwIBAgIQRrSa+sjJxBpLjoqVurHuDjANBgkqhkiG9w0BAQsFADBk MQswCQYDVQQGEwJOTDEWMBQGA1UECBMNTm9vcmQtSG9sbGFuZDESMBAGA1UEBxMJ QW1zdGVyZGFtMQ8wDQYDVQQKEwZURVJFTkExGDAWBgNVBAMTD1RFUkVOQSBTU0wg Q0EgMjAeFw0xNDExMTcwMDAwMDBaFw0xNzExMTYyMzU5NTlaMIGtMQswCQYDVQQG EwJHQjERMA8GA1UEERMIU08yMiA2UlgxEjAQBgNVBAgTCUhhbXBzaGlyZTETMBEG A1UEBxMKV0lOQ0hFU1RFUjETMBEGA1UECRMKT3dlbnMgUm9hZDEeMBwGA1UEChMV UGV0ZXIgU3ltb25kcyBDb2xsZWdlMRQwEgYDVQQLEwtJVCBTZXJ2aWNlczEXMBUG A1UEAxMOZmlsci5wc2MuYWMudWswggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEK AoIBAQCPBrSKHcyGNY/Eefp/E28Zix67pIxjg8Z9wrwI06HQaJOTvC1+Uh1O491S iqw/WghDG5PjgijLHBF7VGawWCf1L7jXGJMWnDIHCPw8b9JkVjDWdUb70lCqsDGS Qe2uFRhRzOZbaLseqrZte/M3TyIMlachzeAuoLvCNmIioyzxVKxq3Cf2iJKRcrmU E80FJvlRGNPnHCJ49TWSPgS+mH31gxoQLBDqXromnBnlod1/i4lYd4Zxik2yyipR rHjh4vWREExCglnFHe7Tz/ourjjAy9aU4uH25y+zTL+JQt9Ow6W6dgmJpduOgMcK I2SOS9tM/Hd5ywW3qW9jmWPFgcdHAgMBAAGjggFqMIIBZjAfBgNVHSMEGDAWgBRb 0IocmjJb4LXdllQb4YYosP22vTAdBgNVHQ4EFgQU+lXzHYhOp+9UN/pDRXhw+j3/ 3ekwDgYDVR0PAQH/BAQDAgWgMAwGA1UdEwEB/wQCMAAwHQYDVR0lBBYwFAYIKwYB BQUHAwEGCCsGAQUFBwMCMCIGA1UdIAQbMBkwDQYLKwYBBAGyMQECAh0wCAYGZ4EM AQICMDoGA1UdHwQzMDEwL6AtoCuGKWh0dHA6Ly9jcmwudXNlcnRydXN0LmNvbS9U RVJFTkFTU0xDQTIuY3JsMGwGCCsGAQUFBwEBBGAwXjA1BggrBgEFBQcwAoYpaHR0 cDovL2NydC51c2VydHJ1c3QuY29tL1RFUkVOQVNTTENBMi5jcnQwJQYIKwYBBQUH MAGGGWh0dHA6Ly9vY3NwLnVzZXJ0cnVzdC5jb20wGQYDVR0RBBIwEIIOZmlsci5w c2MuYWMudWswDQYJKoZIhvcNAQELBQADggEBAIqlcKYKPFoNWBC7WtCRtL1lCHLT 5e+47qkvjTFbNoGbQcZX9xDAGbwjZX/cZY4OE020HwowaorFBsOBFGUaEjKrTTel 0Yz9hZI6EKkndnCV1WXotj+fjWf7rqTONG8VYzunrhmtVkymXYa5o13EqeaaoVX6 wE20UB2KrqU4O7d6rDPjlnZvLrQwtAhof4M0DL6dZ9I1lquMMcOFrmOkN0eg5SQS WmJtZkLRc8W+58EiHBW1/qYexcSrCnuM3/gClH5AlX0hFnZjELTEM7G0P6CxWYpF F0fm6yQ2OO/KChNrW+fKt991O1ot+6ah4DXpcWxQjPQjwW9JQ43OTkAKxUE= -----END CERTIFICATE-----

Public Key (PEM)

-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAjwa0ih3MhjWPxHn6fxNv GYseu6SMY4PGfcK8CNOh0GiTk7wtflIdTuPdUoqsP1oIQxuT44IoyxwRe1RmsFgn 9S+41xiTFpwyBwj8PG/SZFYw1nVG+9JQqrAxkkHtrhUYUczmW2i7Hqq2bXvzN08i DJWnIc3gLqC7wjZiIqMs8VSsatwn9oiSkXK5lBPNBSb5URjT5xwiePU1kj4Evph9 9YMaECwQ6l66JpwZ5aHdf4uJWHeGcYpNssoqUax44eL1kRBMQoJZxR3u08/6Lq44 wMvWlOLh9ucvs0y/iULfTsOlunYJiaXbjoDHCiNkjkvbTPx3ecsFt6lvY5ljxYHH RwIDAQAB -----END PUBLIC KEY-----

ASN1 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 93983716499740893122633653772776238606 . . . . . . . . [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 'NL' . . . . . . . . . . . . [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 'Noord-Holland' . . . . . . . . . . . . [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 'Amsterdam' . . . . . . . . . . . . [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 'TERENA' . . . . . . . . . . . . [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 'TERENA SSL CA 2' . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2014-11-17 00:00:00 +0000 UTC . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2017-11-16 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 2.5.4.6 (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 2.5.4.17 (postalCode) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'SO22 6RX' . . . . . . . . . . . . [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 'Hampshire' . . . . . . . . . . . . [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 'WINCHESTER' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.9 (streetAddress) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Owens Road' . . . . . . . . . . . . [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 'Peter Symonds College' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.11 (organizationalUnitName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'IT Services' . . . . . . . . . . . . [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 'filr.psc.ac.uk' . . . . . . . . [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 18055384083520681291063372469295214397953500450454499518943867987996953959515728335110671634065476751513576605720559232461468076050467115005891058612178600072257096367368739739419051680368690208575655522051153188150524283422119069863650950452895259756797710745981929444684850590932754445698563910101001961890585912503961010787082896126141626187993692556846569061429182241612909274309024712692572808592976193840042585847605839902576467773625122618427716776480665303851842654752532169279458746182093307082749406224125661605962697717138931607688028615652451587575561244308357148420927234941762204921338017907242193504071 . . . . . . . . . . . . . . . . . . . . [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 5bd08a1c9a325be0b5dd96541be18628b0fdb6bd . . . . . . . . . . . . . . . . [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) fa55f31d884ea7ef5437fa43457870fa3dffdde9 . . . . . . . . . . . . . . . . [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 (27 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.4.1.6449.1.2.2.29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.23.140.1.2.2 (Organization Validation Certificates Policy) . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.31 (cRLDistributionPoints) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (51 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|true] OtherName . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|true] OtherName . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:6|false] IA5String 'http://crl.usertrust.com/TERENASSLCA2.crl' . . . . . . . . . . . . . . . . [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 (96 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.usertrust.com/TERENASSLCA2.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.usertrust.com' . . . . . . . . . . . . . . . . [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 (18 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'filr.psc.ac.uk' . . . . [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) 008aa570a60a3c5a0d5810bb5ad091b4bd650872d3e5efb8eea92f8d315b36819b41c657f710c019bc23657fdc658e0e134db41f0a306a8ac506c38114651a1232ab4d37a5d18cfd85923a10a927767095d565e8b63f9f8d67fbaea4ce346f15633ba7ae19ad564ca65d86b9a35dc4a9e69aa155fac04db4501d8aaea5383bb77aac33e396766f2eb430b408687f83340cbe9d67d23596ab8c31c385ae63a43747a0e524125a626d6642d173c5bee7c1221c15b5fea61ec5c4ab0a7b8cdff802947e40957d2116766310b4c433b1b43fa0b1598a451747e6eb243638efca0a136b5be7cab7df753b5a2dfba6a1e035e9716c508cf423c16f49438dce4e400ac541