C

Validate JWS Using HMAC SHA-256

See more JSON Web Signatures (JWS) Examples

Validates a JSON Web Signature (JWS) using HMAC SHA-256. C

#include <C_CkJws.h>
#include <C_CkJsonObject.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkJws jws;
    const char *hmacKey;
    int signatureIndex;
    const char *jwsCompact;
    int v;
    HCkJsonObject joseHeader;

    success = FALSE;

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

    //  This example takes a JSON signature in compact serialization format,
    //  and uses a MAC key to validate and recover the protected header and payload.

    jws = CkJws_Create();

    //  Set the HMAC key:
    hmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow";
    signatureIndex = 0;
    CkJws_SetMacKey(jws,signatureIndex,hmacKey,"base64url");

    //  Load the JWS.
    jwsCompact = "eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk";
    success = CkJws_LoadJws(jws,jwsCompact);

    //  Validate the 1st (and only) signature at index 0..
    v = CkJws_Validate(jws,signatureIndex);
    if (v < 0) {
        //  Perhaps Chilkat was not unlocked or the trial expired..
        printf("Method call failed for some other reason.\n");
        printf("%s\n",CkJws_lastErrorText(jws));
        CkJws_Dispose(jws);
        return;
    }

    if (v == 0) {
        printf("Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both.\n");
        CkJws_Dispose(jws);
        return;
    }

    //  If we get here, the signature was validated..
    printf("Signature validated.\n");

    //  Recover the original content:
    printf("Recovered content:\n");
    printf("%s\n",CkJws_getPayload(jws,"utf-8"));

    //  Examine the protected header:

    joseHeader = CkJsonObject_Create();
    success = CkJws_GetProtectedH(jws,signatureIndex,joseHeader);
    if (success == FALSE) {
        printf("%s\n",CkJws_lastErrorText(jws));
        CkJws_Dispose(jws);
        CkJsonObject_Dispose(joseHeader);
        return;
    }

    CkJsonObject_putEmitCompact(joseHeader,FALSE);

    printf("Protected (JOSE) header:\n");
    printf("%s\n",CkJsonObject_emit(joseHeader));

    //  Output:

    //  	Signature validated.
    //  	Recovered content:
    //  	{"iss":"joe",
    //  	 "exp":1300819380,
    //  	 "http://example.com/is_root":true}
    //  	Protected (JOSE) header:
    //  	{ 
    //  	  "typ": "JWT",
    //  	  "alg": "HS256"
    //  	}


    CkJws_Dispose(jws);
    CkJsonObject_Dispose(joseHeader);

    }