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C

Create a JWS into a StringBuilder

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.CreateJwsSb, which creates a JWS and writes it into a StringBuilder.

Background. JWS (JSON Web Signature) integrity-protects a payload with a signature or MAC. The header alg names the algorithm; this example uses HMAC-SHA256 (HS256) with a symmetric MAC key.

Chilkat C Downloads

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

void ChilkatSample(void)
    {
    BOOL success;
    HCkJws jws;
    HCkJsonObject header;
    BOOL bIncludeBom;
    const char *base64Key;
    HCkStringBuilder sbJws;

    success = FALSE;

    jws = CkJws_Create();

    //  Set the protected header for signer 0, specifying the signature algorithm (alg).
    header = CkJsonObject_Create();
    CkJsonObject_UpdateString(header,"alg","HS256");
    success = CkJws_SetProtectedHeader(jws,0,header);
    if (success == FALSE) {
        printf("%s\n",CkJws_lastErrorText(jws));
        CkJws_Dispose(jws);
        CkJsonObject_Dispose(header);
        return;
    }

    //  Set the payload to be signed.
    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;
    }

    //  Provide the HMAC key (base64) for signer 0.  In production, obtain the key from a secure source
    //  rather than hard-coding it.
    base64Key = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=";
    success = CkJws_SetMacKey(jws,0,base64Key,"base64");
    if (success == FALSE) {
        printf("%s\n",CkJws_lastErrorText(jws));
        CkJws_Dispose(jws);
        CkJsonObject_Dispose(header);
        return;
    }

    //  Create the JWS and write it into a StringBuilder.
    sbJws = CkStringBuilder_Create();
    success = CkJws_CreateJwsSb(jws,sbJws);
    if (success == FALSE) {
        printf("%s\n",CkJws_lastErrorText(jws));
        CkJws_Dispose(jws);
        CkJsonObject_Dispose(header);
        CkStringBuilder_Dispose(sbJws);
        return;
    }

    printf("%s\n",CkStringBuilder_getAsString(sbJws));


    CkJws_Dispose(jws);
    CkJsonObject_Dispose(header);
    CkStringBuilder_Dispose(sbJws);

    }