Load a Private Key from a JWK

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Demonstrates the Chilkat PrivateKey.LoadJwk method, which loads a private key from JWK (JSON Web Key) JSON. The only argument is the JWK JSON string. Supported key types are RSA, EC, and Ed25519 (kty=OKP).

Background: JWK is the JSON key format used throughout modern web security — JWT signing, OAuth, OpenID Connect — so this loader is what you use to consume a key from a JWK Set or an identity provider. A private JWK includes the private parameters (d and, for RSA, the CRT values); a public-only JWK omits them. As JSON in the clear, a private JWK must be handled as sensitive material.

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#include <C_CkPrivateKey.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPrivateKey privKey;
    const char *jwk;

    success = FALSE;

    //  Demonstrates the PrivateKey.LoadJwk method, which loads a private key from JWK (JSON Web Key)
    //  JSON.  The only argument is the JWK JSON string.  Supported key types are RSA, EC, and
    //  Ed25519 (kty=OKP).

    privKey = CkPrivateKey_Create();

    //  A private JWK.  For a real key, "d" (and the other private parameters) would be present.
    jwk = "{\"kty\":\"EC\",\"crv\":\"P-256\",\"x\":\"...\",\"y\":\"...\",\"d\":\"...\"}";

    success = CkPrivateKey_LoadJwk(privKey,jwk);
    if (success == FALSE) {
        printf("%s\n",CkPrivateKey_lastErrorText(privKey));
        CkPrivateKey_Dispose(privKey);
        return;
    }

    printf("Loaded a %s private key.\n",CkPrivateKey_keyType(privKey));


    CkPrivateKey_Dispose(privKey);

    }