Unicode C

How to Generate a JSON Web Key (JWK)

See more JSON Web Signatures (JWS) Examples

Demonstrates how to generate the following types of JSON Web Keys:

• RSA key pair
• EC key pair
• Octet sequence key (HMAC-256)
• 192-bit AES GCM key

Unicode C

#include <C_CkRsaW.h>
#include <C_CkPrivateKeyW.h>
#include <C_CkJsonObjectW.h>
#include <C_CkPrngW.h>
#include <C_CkEccW.h>
#include <C_CkCrypt2W.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkRsaW rsa;
    HCkPrivateKeyW rsaKey;
    const wchar_t *rsaJwkStr;
    HCkJsonObjectW json;
    HCkPrngW prng;
    HCkEccW ecc;
    HCkPrivateKeyW ecKey;
    const wchar_t *ecJwkStr;
    HCkCrypt2W crypt;
    HCkJsonObjectW jwkHmac;
    HCkJsonObjectW jwkAes;

    success = FALSE;

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

    // ----------------------------------------------
    // Generate an RSA key pair in JWK format.
    // (Examples for generating other key types are shown below...)
    rsa = CkRsaW_Create();
    rsaKey = CkPrivateKeyW_Create();
    success = CkRsaW_GenKey(rsa,2048,rsaKey);
    if (success == FALSE) {
        wprintf(L"%s\n",CkRsaW_lastErrorText(rsa));
        CkRsaW_Dispose(rsa);
        CkPrivateKeyW_Dispose(rsaKey);
        return;
    }

    rsaJwkStr = CkPrivateKeyW_getJwk(rsaKey);

    // The string returned is the most compact possible, and therefore it is not
    // very readable.  To pretty-print, load into a JSON object and emit..
    json = CkJsonObjectW_Create();
    CkJsonObjectW_putEmitCompact(json,FALSE);
    CkJsonObjectW_Load(json,rsaJwkStr);
    wprintf(L"%s\n",CkJsonObjectW_emit(json));

    // Sample RSA JWK:

    // { 
    //   "kty": "RSA",
    //   "n": "6w1Xpof7gKmytJ3yc_yjI5_K3MvVXnBYBDy5Oh2W6Xqu_fOl3W18SjS2AU5xJrTHlB_j84yQjPyXJh_ixjACK4K4dCSYqlLmn3R7QJ84vnHLIEkqwUICqOHdCBjK5xhMrdZxIhuNlJzbARY-3u9RqjsT3HYTjA6JNHUWTYBBRou4gYGm4cJgvX4uexdikqxnze014RmZMaOV_4MR--WL4G8QfNJ2pRBEXQeKyije89H6M5oTSK7KZqFTIqu9hwNtx2oGpGAIcS0Jv5xVl-hDtwXZNwQJaOxMzLw1nwnb2kMliJa67EabQFrQY_xthQNsfzcHJJlpqYiMprW8wRkzmQ",
    //   "e": "AQAB",
    //   "d": "1_bnXMw-SeYhmxAwb19lqVqtMpdaES5ZwHLmoT4EpbsiQ5T1BfENrMSnoaWoEy8w3Kk8cU7qlY-TdOUBIKWFqOKvhY8GciA_Y6zLfgGNSnYVczGmxfBXr0HvKvxUmWZbNbH9OqBkQnKoSmRdGcp7l1Q2mG4o4ZuNdxRJjKXV0_DTrNLUJzst0hsfoZ6mWUrQcn39XGvvLjz9ySS-DYGI1vli3ayx8jVNuw0rU8UXVs9WmPQLvZO_ZDMhoLEeKsdejnNkUNPAUjqxcSOZRojt4BfCmbt-_1slFb0NsoaqnDVZGezd9J9ocxGuyIWHAJu9GGZEcdaFyiDDs_WA1IS_fQ",
    //   "p": "9dU8f6yOklRcpV6ayVMKpyQ6AMuBTF3rZmB498eAvvTkVG1-upm8IkikTVNpPjEalc82Sxuq8oF4N5x1-F33sgVEoCZG-1WFZTn-rnPnXSALES9hqSaVYEwnh61EiY8ckjBVr9jD2nL1JKdbfgVVeo69-9PdjnKYYDVL8eLNPwM",
    //   "q": "9MX2sW0GyaOsZ86AYe3eG2ZgcgKHvhJa573gih5Jvi2e-Nv-L0EVK29_DA7n0Pjm-gl9zVAsGsMMkphJyEF9QgyUlJ-59XLqWnECS5gO6WZdtHrJxVvcO-_AOrLIxeYnYcwhmaVaxs_UEpqGzupKHCWgf4cfXe49lrIsqGKH4jM",
    //   "dp": "IQgj9uvSxGq9gCL0HXUhC1Bc0tqFZyN_i-QOnQybig0R2R5VVvFtTBYCrbk1fPvQHK0ZGIKBN9CZvK8zUsodjDgU_ofmJcNaBz4BsKM2RVcW5Zo-PyJGFAhnj12CxhEKv8Hq4ZP4zROBSQmLy6Uf1TX05S-Up51SSCshJ0FYXs0",
    //   "dq": "RijsMiUfGfL5OvP85pUI4e-xW1yQThHyzpQlZVGTL5jiBVEBhcfw6ndWAj3Pgp2ljyvjTFNboPwhgW93Tpg-8AytFgDGi605sVzNHJ_kPlBiMZY0eYaAFQn-npSaaecziJu7UdAMugneLsruMycCwRij7Ynsmr7sFmLR3B4J9vM",
    //   "qi": "jZE-a1pa8YjflpCSH5oqp1f6f6I6-hpZcLdamLCoAcjVSIPk86gtXtOFES4411-DqYzYIZM6B_g_SRYY6JpKAOuZ40mmMTlnIEoVf8BHiGl3g6bBAiN1yQGXrwXJsg2OYnocyRA-xWNdcMSSFA52SwEdar2Mmw29qVzxtC1QbpA"
    // }

    // ----------------------------------------------
    // Generate an EC P-256 key pair in JWK format

    prng = CkPrngW_Create();
    ecc = CkEccW_Create();
    ecKey = CkPrivateKeyW_Create();
    CkEccW_GenKey(ecc,L"P-256",prng,ecKey);

    ecJwkStr = CkPrivateKeyW_getJwk(ecKey);
    CkJsonObjectW_Load(json,ecJwkStr);
    wprintf(L"%s\n",CkJsonObjectW_emit(json));

    // Sample EC JWK Key:
    // { 
    //   "kty": "EC",
    //   "crv": "P-256",
    //   "x": "tDeeYABgKEAbWicYPCEEI8sP4SRIhHKcHDW7VqrB4LA",
    //   "y": "J08HOoIZ0rX2Me3bNFZUltfxIk1Hrc8FsLu8VaSxsMI",
    //   "d": "-bqt1T0wNAN8sP5ruycQZRVlMlt3V_dSwlJ60xAX5io"
    // }

    // ----------------------------------------------
    // Octet sequence keys are intended for representing secret keys, such as HMAC keys and AES keys.

    // We'll use crypt to generate a random UUID..
    crypt = CkCrypt2W_Create();

    // AES and HMAC keys are simply random arrays of bytes
    // For these, we can just build the JSON directly,
    // with the help of the PRNG object.

    jwkHmac = CkJsonObjectW_Create();
    CkJsonObjectW_putEmitCompact(jwkHmac,FALSE);

    // Generate a 256-bit HMAK key (32 bytes)
    CkJsonObjectW_AppendString(jwkHmac,L"kty",L"oct");
    // Give the key an optional ID, which can be anything, even strings as simple as "1", "2", etc.
    CkJsonObjectW_AppendString(jwkHmac,L"kid",CkCrypt2W_generateUuid(crypt));
    // Indicate the intended key alg (optional)
    CkJsonObjectW_AppendString(jwkHmac,L"alg",L"HS256");
    // Generate the actual key bytes
    CkJsonObjectW_AppendString(jwkHmac,L"k",CkPrngW_genRandom(prng,32,L"base64url"));

    wprintf(L"%s\n",CkJsonObjectW_emit(jwkHmac));

    // Sample HMAC-256 JWK:

    // { 
    //   "kty": "oct",
    //   "kid": "06c2515d-41fb-e436-e405-3abb361f5f7a",
    //   "alg": "HS256",
    //   "k": "wR32w7yiMe5Lhb1vkW2koBpoMxpXTFYuxOYCCIEKjdE"
    // }

    // ----------------------------------------------
    // Now generate a 192-bit (24 byte) key that could be used with AES192GCM

    jwkAes = CkJsonObjectW_Create();
    CkJsonObjectW_putEmitCompact(jwkAes,FALSE);

    CkJsonObjectW_AppendString(jwkAes,L"kty",L"oct");
    CkJsonObjectW_AppendString(jwkAes,L"kid",L"2");
    CkJsonObjectW_AppendString(jwkAes,L"k",CkPrngW_genRandom(prng,24,L"base64url"));

    wprintf(L"%s\n",CkJsonObjectW_emit(jwkAes));

    // Sample AES key:
    // { 
    //   "kty": "oct",
    //   "kid": "2",
    //   "k": "akAkq-L_ZTZ6-tEIhDUMtU2ENhsEgL-p"
    // }


    CkRsaW_Dispose(rsa);
    CkPrivateKeyW_Dispose(rsaKey);
    CkJsonObjectW_Dispose(json);
    CkPrngW_Dispose(prng);
    CkEccW_Dispose(ecc);
    CkPrivateKeyW_Dispose(ecKey);
    CkCrypt2W_Dispose(crypt);
    CkJsonObjectW_Dispose(jwkHmac);
    CkJsonObjectW_Dispose(jwkAes);

    }