(C) Create JWS using the Flattened JSON Serialization Format

Creates a JSON Web Signature (JWS) containing 1 signature and output using the flattened JSON serialization format.

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

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

void ChilkatSample(void)
    {
    HCkStringBuilder sbEccJwk;
    HCkPrivateKey eccKey;
    BOOL success;
    HCkJsonObject jwsProtHdr;
    HCkJsonObject jwsUnprotHdr;
    HCkJws jws;
    BOOL bIncludeBom;
    const char *payloadStr;
    const char *jwsStr;
    HCkJsonObject json;

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

    // Note: This example requires Chilkat v9.5.0.66 or greater.

    // The JWS to be created will contain one signature using an ECDSA key.

    sbEccJwk = CkStringBuilder_Create();
    CkStringBuilder_Append(sbEccJwk,"{\"kty\":\"EC\",");
    CkStringBuilder_Append(sbEccJwk,"\"crv\":\"P-256\",");
    CkStringBuilder_Append(sbEccJwk,"\"x\":\"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU\",");
    CkStringBuilder_Append(sbEccJwk,"\"y\":\"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0\",");
    CkStringBuilder_Append(sbEccJwk,"\"d\":\"jpsQnnGQmL-YBIffH1136cspYG6-0iY7X1fCE9-E9LI\"");
    CkStringBuilder_Append(sbEccJwk,"}");

    eccKey = CkPrivateKey_Create();
    // Note: This example loads the ECDSA key from JWK format.  Any format can be loaded
    // into the private key object. (See the online reference documentation..)
    success = CkPrivateKey_LoadJwk(eccKey,CkStringBuilder_getAsString(sbEccJwk));
    if (success != TRUE) {
        printf("%s\n",CkPrivateKey_lastErrorText(eccKey));
        CkStringBuilder_Dispose(sbEccJwk);
        CkPrivateKey_Dispose(eccKey);
        return;
    }

    // ---------------------------------------------------
    // Prepare both a protected and unprotected header.

    jwsProtHdr = CkJsonObject_Create();
    CkJsonObject_AppendString(jwsProtHdr,"alg","ES256");

    jwsUnprotHdr = CkJsonObject_Create();
    CkJsonObject_AppendString(jwsUnprotHdr,"kid","myEcKey");

    // ---------------------------------------------------
    jws = CkJws_Create();

    CkJws_SetProtectedHeader(jws,0,jwsProtHdr);
    CkJws_SetUnprotectedHeader(jws,0,jwsUnprotHdr);

    CkJws_SetPrivateKey(jws,0,eccKey);

    bIncludeBom = FALSE;
    payloadStr = "In our village, folks say God crumbles up the old moon into stars.";
    CkJws_SetPayload(jws,payloadStr,"utf-8",bIncludeBom);

    // ---------------------------------------------------
    // Create the JWS.
    // Indicate we prefer the non-compact, flattened serialization.
    CkJws_putPreferCompact(jws,FALSE);
    CkJws_putPreferFlattened(jws,TRUE);

    jwsStr = CkJws_createJws(jws);
    if (CkJws_getLastMethodSuccess(jws) != TRUE) {
        printf("%s\n",CkJws_lastErrorText(jws));
        CkStringBuilder_Dispose(sbEccJwk);
        CkPrivateKey_Dispose(eccKey);
        CkJsonObject_Dispose(jwsProtHdr);
        CkJsonObject_Dispose(jwsUnprotHdr);
        CkJws_Dispose(jws);
        return;
    }

    // The jwsStr is contains the flattened JSON in the smallest possible size, which is a single line.
    // To get in human-readable format, load into a Chilkat JSON object and emit..
    json = CkJsonObject_Create();
    CkJsonObject_Load(json,jwsStr);
    CkJsonObject_putEmitCompact(json,FALSE);
    printf("%s\n",CkJsonObject_emit(json));

    // Sample output:

    // { 
    //   "payload": "SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu",
    //   "protected": "eyJhbGciOiJFUzI1NiJ9",
    //   "header": { 
    //     "kid": "myEcKey"
    //   },
    //   "signature": "b7V2UpDPytr-kMnM_YjiQ3E0J2ucOI9LYA7mt57vccrK1rb84j9areqgQcJwOA00aWGoz4hf6sMTBfobdcJEGg"
    // }


    CkStringBuilder_Dispose(sbEccJwk);
    CkPrivateKey_Dispose(eccKey);
    CkJsonObject_Dispose(jwsProtHdr);
    CkJsonObject_Dispose(jwsUnprotHdr);
    CkJws_Dispose(jws);
    CkJsonObject_Dispose(json);

    }