C

Create JWT Using HS256, HS384, or HS512

See more JSON Web Token (JWT) Examples

Demonstrates how to create a JWT using HS256, HS384, or HS512. (HS256 is JWT's acronym for HMAC-SHA256.) When HMAC is used, the secret is a shared secret (i.e. password) that both client and server know beforehand.

This example also demonstrates how to include time constraints:

• nbf: Not Before Time
• exp: Expiration Time
• iat: Issue At Time

C

#include <C_CkJwt.h>
#include <C_CkJsonObject.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkJwt jwt;
    HCkJsonObject jose;
    HCkJsonObject claims;
    int curDateTime;
    const char *strJwt;

    success = FALSE;

    // Demonstrates how to create an HMAC JWT using a shared secret (password).

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

    jwt = CkJwt_Create();

    // Build the JOSE header
    jose = CkJsonObject_Create();
    // Use HS256.  Pass the string "HS384" or "HS512" to use a different algorithm.
    success = CkJsonObject_AppendString(jose,"alg","HS256");
    success = CkJsonObject_AppendString(jose,"typ","JWT");

    // Now build the JWT claims (also known as the payload)
    claims = CkJsonObject_Create();
    success = CkJsonObject_AppendString(claims,"iss","http://example.org");
    success = CkJsonObject_AppendString(claims,"sub","John");
    success = CkJsonObject_AppendString(claims,"aud","http://example.com");

    // Set the timestamp of when the JWT was created to now.
    curDateTime = CkJwt_GenNumericDate(jwt,0);
    success = CkJsonObject_AddIntAt(claims,-1,"iat",curDateTime);

    // Set the "not process before" timestamp to now.
    success = CkJsonObject_AddIntAt(claims,-1,"nbf",curDateTime);

    // Set the timestamp defining an expiration time (end time) for the token
    // to be now + 1 hour (3600 seconds)
    success = CkJsonObject_AddIntAt(claims,-1,"exp",curDateTime + 3600);

    // Produce the smallest possible JWT:
    CkJwt_putAutoCompact(jwt,TRUE);

    strJwt = CkJwt_createJwt(jwt,CkJsonObject_emit(jose),CkJsonObject_emit(claims),"secret");

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


    CkJwt_Dispose(jwt);
    CkJsonObject_Dispose(jose);
    CkJsonObject_Dispose(claims);

    }