(MFC) Load ECC Public Key from JWK Format (JSON Web Key)

Demonstrates how to load an ECC public key from JWK (JSON Web Key) format.

Note: This example requires Chilkat v9.5.0.66 or later.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkJsonObject.h>
#include <CkPublicKey.h>

void ChilkatSample(void)
    {
    CkString strOut;

    // Note: This example requires Chilkat v9.5.0.66 or later.
    bool success;

    // First build a JWK sample to load..
    CkJsonObject json;
    json.UpdateString("kty","EC");
    json.UpdateString("crv","P-256");
    json.UpdateString("x","oBUyo8CQAFPeYPvv78ylh5MwFZjTCLQeb042TjiMJxE");
    json.UpdateString("y","vvQyxZkUjJQUPU_0bCy3Pj5qQdfu8jwEfqEeYGZ95CU");

    // The JSON contains the following:
    // { 
    //   "kty": "EC",
    //   "crv": "P-256",
    //   "x": "oBUyo8CQAFPeYPvv78ylh5MwFZjTCLQeb042TjiMJxE",
    //   "y": "vvQyxZkUjJQUPU_0bCy3Pj5qQdfu8jwEfqEeYGZ95CU",
    // }

    // Note: The JSON can contain other members, such as "use", "kid", or anything else.  These will be ignored.
    json.put_EmitCompact(false);

    // Show the JWK string to be loaded:
    const char *jwkStr = json.emit();

    CkPublicKey pubKey;
    // The LoadFromString method will automatically detect the format.
    success = pubKey.LoadFromString(jwkStr);
    if (success != true) {
        strOut.append(pubKey.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // OK.. the JWK is loaded.  It can be used in whatever way desired...

    // The key can be retrieved in any other format, such as XML or PEM..
    strOut.append(pubKey.getXml());
    strOut.append("\r\n");

    // XML output:
    // <ECCPublicKey curve="secp256r1" 
    //    x="A01532A3C0900053DE60FBEFEFCCA58793301598D308B41E6F4E364E388C2711" 
    //    y="BEF432C599148C94143D4FF46C2CB73E3E6A41D7EEF23C047EA11E60667DE425">
    //    MIIBSzCCAQMGByqGSM49AgEwgfcCAQEwLAYHKoZIzj0BAQIhAP////8AAAABAAAAAAAAAAAAAAAA////////////////MFsEIP////8AAAABAAAAAAAAAAAAAAAA///////////////8BCBaxjXYqjqT57PrvVV2mIa8ZR0GsMxTsPY7zjw+J9JgSwMVAMSdNgiG5wSTamZ44ROdJreBn36QBEEEaxfR8uEsQkf4vOblY6RA8ncDfYEt6zOg9KE5RdiYwpZP40Li/hp/m47n60p8D54WK84zV2sxXs7LtkBoN79R9QIhAP////8AAAAA//////////+85vqtpxeehPO5ysL8YyVRAgEBA0IABKAVMqPAkABT3mD77+/MpYeTMBWY0wi0Hm9ONk44jCcRvvQyxZkUjJQUPU/0bCy3Pj5qQdfu8jwEfqEeYGZ95CU=
    // </ECCPublicKey>

    // Choose PCKS1 or PCKS8 PEM format..
    bool bPreferPkcs1 = false;
    strOut.append(pubKey.getPem(bPreferPkcs1));
    strOut.append("\r\n");

    // PEM output
    // -----BEGIN PUBLIC KEY-----
    // MIIBSzCCAQMGByqGSM49AgEwgfcCAQEwLAYHKoZIzj0BAQIhAP////8AAAABAAAA
    // AAAAAAAAAAAA////////////////MFsEIP////8AAAABAAAAAAAAAAAAAAAA////
    // ///////////8BCBaxjXYqjqT57PrvVV2mIa8ZR0GsMxTsPY7zjw+J9JgSwMVAMSd
    // NgiG5wSTamZ44ROdJreBn36QBEEEaxfR8uEsQkf4vOblY6RA8ncDfYEt6zOg9KE5
    // RdiYwpZP40Li/hp/m47n60p8D54WK84zV2sxXs7LtkBoN79R9QIhAP////8AAAAA
    // //////////+85vqtpxeehPO5ysL8YyVRAgEBA0IABKAVMqPAkABT3mD77+/MpYeT
    // MBWY0wi0Hm9ONk44jCcRvvQyxZkUjJQUPU/0bCy3Pj5qQdfu8jwEfqEeYGZ95CU=
    // -----END PUBLIC KEY-----


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }