Golang crypto/x509.ParseCertificate function example

26th June 2017

package crypto/x509

ParseCertificate parses a single certificate from the given ASN.1 DER data.

Golang crypto/x509.ParseCertificate function usage example

 package main

 import (
 "crypto/x509"
 "fmt"
 "encoding/pem"
 )


 func main() {

 var pemData = `-----BEGIN CERTIFICATE-----
 MIIGCDCCA/CgAwIBAgIQKy5u6tl1NmwUim7bo3yMBzANBgkqhkiG9w0BAQwFADCB
 hTELMAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4G
 A1UEBxMHU2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxKzApBgNV
 BAMTIkNPTU9ETyBSU0EgQ2VydGlmaWNhdGlvbiBBdXRob3JpdHkwHhcNMTQwMjEy
 MDAwMDAwWhcNMjkwMjExMjM1OTU5WjCBkDELMAkGA1UEBhMCR0IxGzAZBgNVBAgT
 EkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMR
 Q09NT0RPIENBIExpbWl0ZWQxNjA0BgNVBAMTLUNPTU9ETyBSU0EgRG9tYWluIFZh
 bGlkYXRpb24gU2VjdXJlIFNlcnZlciBDQTCCASIwDQYJKoZIhvcNAQEBBQADggEP
 ADCCAQoCggEBAI7CAhnhoFmk6zg1jSz9AdDTScBkxwtiBUUWOqigwAwCfx3M28Sh
 bXcDow+G+eMGnD4LgYqbSRutA776S9uMIO3Vzl5ljj4Nr0zCsLdFXlIvNN5IJGS0
 Qa4Al/e+Z96e0HqnU4A7fK31llVvl0cKfIWLIpeNs4TgllfQcBhglo/uLQeTnaG6
 ytHNe+nEKpooIZFNb5JPJaXyejXdJtxGpdCsWTWM/06RQ1A/WZMebFEh7lgUq/51
 UHg+TLAchhP6a5i84DuUHoVS3AOTJBhuyydRReZw3iVDpA3hSqXttn7IzW3uLh0n
 c13cRTCAquOyQQuvvUSH2rnlG51/ruWFgqUCAwEAAaOCAWUwggFhMB8GA1UdIwQY
 MBaAFLuvfgI9+qbxPISOre44mOzZMjLUMB0GA1UdDgQWBBSQr2o6lFoL2JDqElZz
 30O0Oija5zAOBgNVHQ8BAf8EBAMCAYYwEgYDVR0TAQH/BAgwBgEB/wIBADAdBgNV
 HSUEFjAUBggrBgEFBQcDAQYIKwYBBQUHAwIwGwYDVR0gBBQwEjAGBgRVHSAAMAgG
 BmeBDAECATBMBgNVHR8ERTBDMEGgP6A9hjtodHRwOi8vY3JsLmNvbW9kb2NhLmNv
 bS9DT01PRE9SU0FDZXJ0aWZpY2F0aW9uQXV0aG9yaXR5LmNybDBxBggrBgEFBQcB
 AQRlMGMwOwYIKwYBBQUHMAKGL2h0dHA6Ly9jcnQuY29tb2RvY2EuY29tL0NPTU9E
 T1JTQUFkZFRydXN0Q0EuY3J0MCQGCCsGAQUFBzABhhhodHRwOi8vb2NzcC5jb21v
 ZG9jYS5jb20wDQYJKoZIhvcNAQEMBQADggIBAE4rdk+SHGI2ibp3wScF9BzWRJ2p
 mj6q1WZmAT7qSeaiNbz69t2Vjpk1mA42GHWx3d1Qcnyu3HeIzg/3kCDKo2cuH1Z/
 e+FE6kKVxF0NAVBGFfKBiVlsit2M8RKhjTpCipj4SzR7JzsItG8kO3KdY3RYPBps
 P0/HEZrIqPW1N+8QRcZs2eBelSaz662jue5/DJpmNXMyYE7l3YphLG5SEXdoltMY
 dVEVABt0iN3hxzgEQyjpFv3ZBdRdRydg1vs4O2xyopT4Qhrf7W8GjEXCBgCq5Ojc
 2bXhc3js9iPc0d1sjhqPpepUfJa3w/5Vjo1JXvxku88+vZbrac2/4EjxYoIQ5QxG
 V/Iz2tDIY+3GH5QFlkoakdH368+PUq4NCNk+qKBR6cGHdNXJ93SrLlP7u3r7l+L4
 HyaPs9Kg4DdbKDsx5Q5XLVq4rXmsXiBmGqW5prU5wfWYQ//u+aen/e7KJD2AFsQX
 j4rBYKEMrltDR5FL1ZoXX/nUh8HCjLfn4g8wGTeGrODcQgPmlKidrv0PJFGUzpII
 0fxQ8ANAe4hZ7Q7drNJ3gjTcBpUC2JD5Leo31Rpg0Gcg19hCC0Wvgmje3WYkN5Ap
 lBlGGSW4gNfL1IYoakRwJiNiqZ+Gb7+6kHDSVneFeO/qJakXzlByjAA6quPbYzSf
 +AZxAeKCINT+b72x
 -----END CERTIFICATE-----`

 var block *pem.Block
 var pemByte []byte

 block, pemByte = pem.Decode([]byte(pemData))

 fmt.Println(block)

 fmt.Println(pemByte)

 // just a single certificate
 cert, err := x509.ParseCertificate(block.Bytes)

 if err != nil {
 fmt.Println(err)
 }

 // test the cert
 certPool := x509.NewCertPool()
 certPool.AddCert(cert)

 }

NOTE : To parse multiple certificates, see https://www.socketloop.com/references/golang-crypto-x509-parsecertificates-function-example

Reference :

http://golang.org/pkg/crypto/x509/#ParseCertificate