www.coffeyvillecrude.com

Issued by VeriSign Class 3 Secure Server CA - G3

About this certificate


This digital certificate with serial number 49:bb:46:86:6a:78:b1:93:00:b5:4b:ae:49:23:34:36 was issued on by VeriSign, Inc. .

While the 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.

Cerificate errors/warnings *beta

  • WARNING: Using depricated TeletexString for '[Kansas City]'
  • WARNING: Using depricated TeletexString for '[CVR Energy, Inc]'
  • WARNING: Using depricated TeletexString for '[IT]'
  • WARNING: Using depricated TeletexString for '[www.coffeyvillecrude.com]'

CVR Energy, Inc

Organization: CVR Energy, Inc
Organization unit: IT
State / Province: Kansas
Locality: Kansas City
Country: US

VeriSign, Inc.

Organization: VeriSign, Inc.
Organization unit: VeriSign Trust Network
Organization unit: Terms of use at https://www.verisign.com/rpa (c)10
State / Province: Kansas
Locality: Kansas City
Country: US

Time since certificate expired

This certificate has expire since

Certificate Details

Serial Number (hex): 49:bb:46:86:6a:78:b1:93:00:b5:4b:ae:49:23:34:36
Serial Number (int): 98006033623042224726870241787515188278
Serial Number lenght: 127 bits, 16 octets

SubjectKeyId:
AuthorityKeyId: 0d:44:5c:16:53:44:c1:82:7e:1d:20:ab:25:f4:01:63:d8:be:79:a5

Fingerprint (sha1): 07:2b:eb:2c:c5:4b:51:22:3d:f7:d0:fd:b1:c5:cd:48:eb:ff:a1:fa
Fingerprint (sha256): fe:8c:51:45:10:ab:24:6a:cc:da:84:bd:b7:36:6d:40:22:2c:02:fe:c4:e9:0f:ad:a9:16:71:c9:ec:42:c4:05

Issuing Certificate URL: http://sd.symcb.com/sd.crt

Revocation information

OCSP Server: http://sd.symcd.com
CRL Distribution Point: http://sd.symcb.com/sd.crl

Check the revocation status for the current certificate on www.coffeyvillecrude.com
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

SHA1 with RSA



Key Usage

Digital Signature
Key Encipherment

Extended Key Usages

Server Authentication
Client Authentication

Extensions

8 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: www.coffeyvillecrude.com

Certificate

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

Certificate (PEM)

-----BEGIN CERTIFICATE----- MIIFMTCCBBmgAwIBAgIQSbtGhmp4sZMAtUuuSSM0NjANBgkqhkiG9w0BAQUFADCB tTELMAkGA1UEBhMCVVMxFzAVBgNVBAoTDlZlcmlTaWduLCBJbmMuMR8wHQYDVQQL ExZWZXJpU2lnbiBUcnVzdCBOZXR3b3JrMTswOQYDVQQLEzJUZXJtcyBvZiB1c2Ug YXQgaHR0cHM6Ly93d3cudmVyaXNpZ24uY29tL3JwYSAoYykxMDEvMC0GA1UEAxMm VmVyaVNpZ24gQ2xhc3MgMyBTZWN1cmUgU2VydmVyIENBIC0gRzMwHhcNMTQwNjI2 MDAwMDAwWhcNMTUwODI1MjM1OTU5WjB+MQswCQYDVQQGEwJVUzEPMA0GA1UECBMG S2Fuc2FzMRQwEgYDVQQHFAtLYW5zYXMgQ2l0eTEYMBYGA1UEChQPQ1ZSIEVuZXJn eSwgSW5jMQswCQYDVQQLFAJJVDEhMB8GA1UEAxQYd3d3LmNvZmZleXZpbGxlY3J1 ZGUuY29tMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAnb+boFxtUe+6 Z4zDwfWb/Nxt6VJICthjMuMtplXNYNsYKC+YfBba5aMn307uMgwR63hiFsg0z8fq K0ueZ77EylxVTuza/imqv+wZnqKY1rCZy7pU6Vn0GGlWCpsyyhJdup1I7YqZRI5H Z+HxYdfv1fOGl4CSik1CJctArLtCMFa5hO3TbXBifkeiw9QwQnTe6UMTthJIlfqq 9/XnX1odMzNP6E+aLGAOechh2HkK8VyhHn7RxjuwZcugkH9LqBcl+tY22WNsgpbf 3HwVhntlOkEs40IU7DcRi1LNm5eRn9AC+UjMW4uRKElp4xl4iaOS9GsYqMNpeOa/ qxvMpZd6XwIDAQABo4IBcTCCAW0wIwYDVR0RBBwwGoIYd3d3LmNvZmZleXZpbGxl Y3J1ZGUuY29tMAkGA1UdEwQCMAAwDgYDVR0PAQH/BAQDAgWgMCsGA1UdHwQkMCIw IKAeoByGGmh0dHA6Ly9zZC5zeW1jYi5jb20vc2QuY3JsMGUGA1UdIAReMFwwWgYK YIZIAYb4RQEHNjBMMCMGCCsGAQUFBwIBFhdodHRwczovL2Quc3ltY2IuY29tL2Nw czAlBggrBgEFBQcCAjAZFhdodHRwczovL2Quc3ltY2IuY29tL3JwYTAdBgNVHSUE FjAUBggrBgEFBQcDAQYIKwYBBQUHAwIwHwYDVR0jBBgwFoAUDURcFlNEwYJ+HSCr JfQBY9i+eaUwVwYIKwYBBQUHAQEESzBJMB8GCCsGAQUFBzABhhNodHRwOi8vc2Qu c3ltY2QuY29tMCYGCCsGAQUFBzAChhpodHRwOi8vc2Quc3ltY2IuY29tL3NkLmNy dDANBgkqhkiG9w0BAQUFAAOCAQEAYfzGrd+SoKOP+gqQpRyULKIN/CqT60EGgYx9 GZ8/w3z4Ph0BiPWF7UGJ7J3AL9/hFozbLZkR5feYS+xn9lAoTa/wIWJ4y2VhypZp NOsRe2w+14UuqGJ2f3OCdcxWMtXmSoJFeiHHfTxCCtOAYcPuL6XyEq3V+evIddVn A5P7qXgVcV7uvYnXSLUUJct0vdT6/ABAUxZkGiR7g9Dw5AbuH7HTb8kMh2tLWJuL VSPSAMokNAGDxzKzptz0tgGc+0UdYiHCVSAkDhmXNML1zwIdrxXsdrWXA3qvTQTP 1z4NZ9wg1U5ox2wFmnFfuDZbOnHArDBuI9i8pD/MeQB7AAuZLA== -----END CERTIFICATE-----

Public Key (PEM)

-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAnb+boFxtUe+6Z4zDwfWb /Nxt6VJICthjMuMtplXNYNsYKC+YfBba5aMn307uMgwR63hiFsg0z8fqK0ueZ77E ylxVTuza/imqv+wZnqKY1rCZy7pU6Vn0GGlWCpsyyhJdup1I7YqZRI5HZ+HxYdfv 1fOGl4CSik1CJctArLtCMFa5hO3TbXBifkeiw9QwQnTe6UMTthJIlfqq9/XnX1od MzNP6E+aLGAOechh2HkK8VyhHn7RxjuwZcugkH9LqBcl+tY22WNsgpbf3HwVhntl OkEs40IU7DcRi1LNm5eRn9AC+UjMW4uRKElp4xl4iaOS9GsYqMNpeOa/qxvMpZd6 XwIDAQAB -----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 98006033623042224726870241787515188278 . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.2.840.113549.1.1.5 (sha1WithRSAEncryption) . . . . . . . . . . . . [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 'VeriSign, Inc.' . . . . . . . . . . . . [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 'VeriSign Trust Network' . . . . . . . . . . . . [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 'Terms of use at https://www.verisign.com/rpa (c)10' . . . . . . . . . . . . [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 'VeriSign Class 3 Secure Server CA - G3' . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2014-06-26 00:00:00 +0000 UTC . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2015-08-25 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 'US' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.8 (stateOrProvinceName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Kansas' . . . . . . . . . . . . [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:20|false] TeletexString, T61String 'Kansas City' . . . . . . . . . . . . [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:20|false] TeletexString, T61String 'CVR Energy, Inc' . . . . . . . . . . . . [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:20|false] TeletexString, T61String 'IT' . . . . . . . . . . . . [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:20|false] TeletexString, T61String 'www.coffeyvillecrude.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 19913899264404292828273853788500920222869561508833213271523190487538675367030761898568133269234066865005178617890390141754162118017337044915245318208115869055963930902780490715753573613552190757375900861744006007045746055616016863615243912746571525408328613337940165748151097975266596123181824027045742205725890623418810907055194401056969983333457719965282058825655008587178588546233594741397739545579484726952206995246040611228771782761635577057782931637144710176296213767374966874272470388210464027403274355946929405385149843830389335997960249091477489211423262142221001705928909969989059271082661498382584680774239 . . . . . . . . . . . . . . . . . . . . [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 2.5.29.17 (subjectAltName) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (28 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.coffeyvillecrude.com' . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.19 (basicConstraints) . . . . . . . . . . . . . . . . . . . . [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 2.5.29.15 (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 2.5.29.31 (cRLDistributionPoints) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (36 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://sd.symcb.com/sd.crl' . . . . . . . . . . . . . . . . [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 (94 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.16.840.1.113733.1.7.54 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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://d.symcb.com/cps' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.2.2 (unotice) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:22|false] IA5String 'https://d.symcb.com/rpa' . . . . . . . . . . . . . . . . [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 2.5.29.35 (authorityKeyIdentifier) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (24 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|false] OtherName 0d445c165344c1827e1d20ab25f40163d8be79a5 . . . . . . . . . . . . . . . . [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 (75 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://sd.symcd.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [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://sd.symcb.com/sd.crt' . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.2.840.113549.1.1.5 (sha1WithRSAEncryption) . . . . . . . . [c:0|t:5|false] NULL . . . . [c:0|t:3|false] BIT STRING (2048 bits) 0061fcc6addf92a0a38ffa0a90a51c942ca20dfc2a93eb4106818c7d199f3fc37cf83e1d0188f585ed4189ec9dc02fdfe1168cdb2d9911e5f7984bec67f650284daff0216278cb6561ca966934eb117b6c3ed7852ea862767f738275cc5632d5e64a82457a21c77d3c420ad38061c3ee2fa5f212add5f9ebc875d5670393fba97815715eeebd89d748b51425cb74bdd4fafc00405316641a247b83d0f0e406ee1fb1d36fc90c876b4b589b8b5523d200ca24340183c732b3a6dcf4b6019cfb451d6221c25520240e199734c2f5cf021daf15ec76b597037aaf4d04cfd73e0d67dc20d54e68c76c059a715fb8365b3a71c0ac306e23d8bca43fcc79007b000b992c