Sign a JWS with a Private Key

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.SetPrivateKey, which sets the private key used to create a signature. The example uses RS256 (RSASSA-PKCS1-v1_5 with SHA-256).

The file path is relative to the application's current working directory. An absolute path may also be used. Supply the path appropriate to your own environment.

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

void ChilkatSample(void)
    {
    BOOL success;
    HCkJws jws;
    HCkJsonObject header;
    BOOL bIncludeBom;
    HCkPrivateKey privKey;
    const char *jwsCompact;

    success = FALSE;

    jws = CkJws_Create();

    //  Protected header specifying RSASSA-PKCS1-v1_5 with SHA-256 (RS256).
    header = CkJsonObject_Create();
    CkJsonObject_UpdateString(header,"alg","RS256");
    success = CkJws_SetProtectedHeader(jws,0,header);
    if (success == FALSE) {
        printf("%s\n",CkJws_lastErrorText(jws));
        CkJws_Dispose(jws);
        CkJsonObject_Dispose(header);
        return;
    }

    bIncludeBom = FALSE;
    success = CkJws_SetPayload(jws,"This is the content to sign.","utf-8",bIncludeBom);
    if (success == FALSE) {
        printf("%s\n",CkJws_lastErrorText(jws));
        CkJws_Dispose(jws);
        CkJsonObject_Dispose(header);
        return;
    }

    //  The file path is relative to the application's current working directory.  An absolute path
    //  may also be used.  Supply the path appropriate to your own environment.
    //  Load the signer's private key and set it for signature 0.
    privKey = CkPrivateKey_Create();
    success = CkPrivateKey_LoadPemFile(privKey,"qa_data/signer_privkey.pem");
    if (success == FALSE) {
        printf("%s\n",CkPrivateKey_lastErrorText(privKey));
        CkJws_Dispose(jws);
        CkJsonObject_Dispose(header);
        CkPrivateKey_Dispose(privKey);
        return;
    }

    success = CkJws_SetPrivateKey(jws,0,privKey);
    if (success == FALSE) {
        printf("%s\n",CkJws_lastErrorText(jws));
        CkJws_Dispose(jws);
        CkJsonObject_Dispose(header);
        CkPrivateKey_Dispose(privKey);
        return;
    }

    jwsCompact = CkJws_createJws(jws);
    if (CkJws_getLastMethodSuccess(jws) == FALSE) {
        printf("%s\n",CkJws_lastErrorText(jws));
        CkJws_Dispose(jws);
        CkJsonObject_Dispose(header);
        CkPrivateKey_Dispose(privKey);
        return;
    }

    printf("%s\n",jwsCompact);


    CkJws_Dispose(jws);
    CkJsonObject_Dispose(header);
    CkPrivateKey_Dispose(privKey);

    }