Unicode C

Get ECC Public Key in JWK Format (JSON Web Key)

See more ECC Examples

Demonstrates how to get an ECC public key in JWK (JSON Web Key) format.

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

Unicode C

#include <C_CkStringBuilderW.h>
#include <C_CkPublicKeyW.h>
#include <C_CkJsonObjectW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkStringBuilderW sbPem;
    HCkPublicKeyW pubKey;
    const wchar_t *jwk;
    HCkJsonObjectW json;

    success = FALSE;

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

    // Load a PEM file into memory.
    sbPem = CkStringBuilderW_Create();
    success = CkStringBuilderW_LoadFile(sbPem,L"qa_data/pem/ecc_public.pem",L"utf-8");
    if (success != TRUE) {
        wprintf(L"Failed to load PEM file.\n");
        CkStringBuilderW_Dispose(sbPem);
        return;
    }

    // Load the PEM into a public key object.
    pubKey = CkPublicKeyW_Create();
    success = CkPublicKeyW_LoadFromString(pubKey,CkStringBuilderW_getAsString(sbPem));
    if (success != TRUE) {
        wprintf(L"%s\n",CkPublicKeyW_lastErrorText(pubKey));
        CkStringBuilderW_Dispose(sbPem);
        CkPublicKeyW_Dispose(pubKey);
        return;
    }

    // Get the public key in JWK format:
    jwk = CkPublicKeyW_getJwk(pubKey);

    // The GetJwk method will return the JWK in the most compact JSON format possible,
    // as a single line with no extra whitespace.  To get a more human-readable JWK (for this example),
    // load into a Chilkat JSON object and emit non-compact:

    json = CkJsonObjectW_Create();
    CkJsonObjectW_Load(json,jwk);
    CkJsonObjectW_putEmitCompact(json,FALSE);
    wprintf(L"ECC Public Key in JWK format:\n");
    wprintf(L"%s\n",CkJsonObjectW_emit(json));

    // Sample output:
    // { 
    //   "kty": "EC",
    //   "crv": "P-256",
    //   "x": "oBUyo8CQAFPeYPvv78ylh5MwFZjTCLQeb042TjiMJxE",
    //   "y": "vvQyxZkUjJQUPU_0bCy3Pj5qQdfu8jwEfqEeYGZ95CU"
    // }
    // 
    // Additional information can be added like this:
    CkJsonObjectW_AppendString(json,L"use",L"enc");
    CkJsonObjectW_AppendString(json,L"kid",L"123ABC");

    // Now examine the JSON:
    wprintf(L"%s\n",CkJsonObjectW_emit(json));

    // { 
    //   "kty": "EC",
    //   "crv": "P-256",
    //   "x": "oBUyo8CQAFPeYPvv78ylh5MwFZjTCLQeb042TjiMJxE",
    //   "y": "vvQyxZkUjJQUPU_0bCy3Pj5qQdfu8jwEfqEeYGZ95CU",
    //   "use": "enc",
    //   "kid": "123ABC"
    // }


    CkStringBuilderW_Dispose(sbPem);
    CkPublicKeyW_Dispose(pubKey);
    CkJsonObjectW_Dispose(json);

    }