(Unicode C) Create JWT Using RSA (RS256, RS384, or RS512)

Demonstrates how to create a JWT using an RSA private key. This is for JOSE headers with an "alg" of RS256, RS384, or RS512. When RSA 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 <C_CkPrivateKeyW.h>
#include <C_CkJwtW.h>
#include <C_CkJsonObjectW.h>

void ChilkatSample(void)
    {
    HCkPrivateKeyW privKey;
    BOOL success;
    HCkJwtW jwt;
    HCkJsonObjectW jose;
    HCkJsonObjectW claims;
    int curDateTime;
    const wchar_t *token;

    // Demonstrates how to create a JWT using an RSA private key.

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

    privKey = CkPrivateKeyW_Create();

    // Load an RSA private key from a PEM file.
    success = CkPrivateKeyW_LoadEncryptedPemFile(privKey,L"qa_data/pem/rsa_passwd.pem",L"passwd");
    if (success != TRUE) {
        wprintf(L"%s\n",CkPrivateKeyW_lastErrorText(privKey));
        CkPrivateKeyW_Dispose(privKey);
        return;
    }

    jwt = CkJwtW_Create();

    // Build the JOSE header
    jose = CkJsonObjectW_Create();
    // Use RS256.  Pass the string "RS384" or "RS512" to use RSA with SHA-384 or SHA-512.
    success = CkJsonObjectW_AppendString(jose,L"alg",L"RS256");
    success = CkJsonObjectW_AppendString(jose,L"typ",L"JWT");

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

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

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

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

    // Produce the smallest possible JWT:
    CkJwtW_putAutoCompact(jwt,TRUE);

    // Create the JWT token.  This is where the RSA signature is created.
    token = CkJwtW_createJwtPk(jwt,CkJsonObjectW_emit(jose),CkJsonObjectW_emit(claims),privKey);

    wprintf(L"%s\n",token);


    CkPrivateKeyW_Dispose(privKey);
    CkJwtW_Dispose(jwt);
    CkJsonObjectW_Dispose(jose);
    CkJsonObjectW_Dispose(claims);

    }