(Java) Get ETK Public Key (api-acpt.ehealth.fgov.be)

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The following URL returns JSON, which contains a PKCS7 signed data:

https://api-acpt.ehealth.fgov.be/etee/v1/etks?identifier=12345678901&type=SSIN

This example extracts the signed data, validates it, and then extracts the public key from the certificate (obtained from signed content in the PKCS7)

Note: The URL above uses "12345678901" which is not valid. You should replace it with a valid number.

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import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkHttp http = new CkHttp();

    String jsonStr = http.quickGetStr("https://api-acpt.ehealth.fgov.be/etee/v1/etks?identifier=12345678901&type=SSIN");
    if (http.get_LastMethodSuccess() == false) {
        System.out.println(http.lastErrorText());
        return;
        }

    System.out.println(jsonStr);

    // The JSON contains something like this:

    // [
    //     {
    //         "key": {
    //             "applicationIdentifier": "",
    //             "ssin": "12345678901"
    //         },
    //         "value": "MIAGCSq....AAAAAAAA=="
    //     }
    // ]

    // Note: The above is a JSON array (not a JSON object)
    // It should be loaded into a Chilkat JSON array.
    CkJsonArray jarr = new CkJsonArray();
    boolean success = jarr.Load(jsonStr);
    if (success == false) {
        System.out.println("Failed to load JSON.");
        return;
        }

    CkJsonObject json = jarr.ObjectAt(0);
    CkBinData bdPkcs7 = new CkBinData();
    bdPkcs7.AppendEncoded(json.stringOf("value"),"base64");

    // Let's verify the PKCS7, and then examine the signing cert,
    // and get the signing cert's public key.
    CkCrypt2 crypt = new CkCrypt2();

    // Validate the signedData PKCS7, and replace the contents of bdPkcs7 with the extracted signed content.
    success = crypt.OpaqueVerifyBd(bdPkcs7);
    if (success == false) {
        System.out.println(crypt.lastErrorText());
        return;
        }

    // The signed content is the DER of a certificate.
    // In other words, bdPkcs7 now contains a certificate.
    CkCert cert = new CkCert();
    success = cert.LoadFromBd(bdPkcs7);
    if (success == false) {
        System.out.println(cert.lastErrorText());
        return;
        }

    // Show some certificate information:
    System.out.println("Subject: " + cert.subjectDN());
    System.out.println("Serial: " + cert.serialNumber());
    System.out.println("Issuer: " + cert.issuerDN());

    // Let's get the cert's public key...
    CkPublicKey pubKey = cert.ExportPublicKey();
    if (cert.get_LastMethodSuccess() == false) {
        System.out.println(cert.lastErrorText());
        return;
        }

    // OK, you now have the public key and can do whatever is needed..
    System.out.println(pubKey.keyType());
    System.out.println(pubKey.get_KeySize());
  }
}