(C++) Create JWT Using ECC (ES256, ES384, or ES512)

Demonstrates how to create a JWT using an ECC private key. This is for JOSE headers with an "alg" of ES256, ES384, or ES512. When ECC is used, the private key signs (creates) the JWT, and the public key is for verification.

This example also demonstrates how to include time constraints:

• nbf: Not Before Time
• exp: Expiration Time
• iat: Issue At Time

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#include <CkPrivateKey.h>
#include <CkJwt.h>
#include <CkJsonObject.h>

void ChilkatSample(void)
    {
    // Demonstrates how to create a JWT using an ECC private key.

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkPrivateKey privKey;

    // Load an ECC private key from a PEM file.
    bool success = privKey.LoadPemFile("qa_data/pem/ecc_privKey.pem");
    if (success != true) {
        std::cout << privKey.lastErrorText() << "\r\n";
        return;
    }

    CkJwt jwt;

    // Build the JOSE header
    CkJsonObject jose;
    // Use ES256.  Pass the string "ES384" or "ES512" to use ECC with SHA-384 or SHA-512.
    success = jose.AppendString("alg","ES256");
    success = jose.AppendString("typ","JWT");

    // Now build the JWT claims (also known as the payload)
    CkJsonObject claims;
    success = claims.AppendString("iss","http://example.org");
    success = claims.AppendString("sub","John");
    success = claims.AppendString("aud","http://example.com");

    // Set the timestamp of when the JWT was created to now.
    int curDateTime = jwt.GenNumericDate(0);
    success = claims.AddIntAt(-1,"iat",curDateTime);

    // Set the "not process before" timestamp to now.
    success = claims.AddIntAt(-1,"nbf",curDateTime);

    // Set the timestamp defining an expiration time (end time) for the token
    // to be now + 1 hour (3600 seconds)
    success = claims.AddIntAt(-1,"exp",curDateTime + 3600);

    // Produce the smallest possible JWT:
    jwt.put_AutoCompact(true);

    // Create the JWT token.  This is where the ECC signature is created.
    const char *token = jwt.createJwtPk(jose.emit(),claims.emit(),privKey);

    std::cout << token << "\r\n";

    // Example output:
    // eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwOi8vZXhhbXBsZS5vcmciLCJzdWIiOiJKb2huIiwiYXVkIjoiaHR0cDovL2V4YW1wbGUuY29tIiwiaWF0IjoxNDg1NzA4NzkyLCJuYmYiOjE0ODU3MDg3OTIsImV4cCI6MTQ4NTcxMjM5Mn0.wqsuyJpxJ073ox-lOiLFqG1lQocXe4hGf2XGZJRrO3qn0UusxI_bu3Gzky8gBsH4sA4u9TWZn5M-1wYMMIJk6Q
    }