(Unicode C) JWE using ECDH-ES, BP-256, A256GCM

See more JSON Web Encryption (JWE) Examples

Create a JWE with the following header:

	{
	  "alg": "ECDH-ES",
	  "enc": "A256GCM",
	  "exp": 1621957030,
	  "cty": "NJWT",
	  "epk": {
	    "kty": "EC",
	    "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w"
	    "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
	    "crv": "BP-256"
	  }
	}

Note: This example requires Chilkat v9.5.0.87 or greater.

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#include <C_CkJsonObjectW.h>
#include <C_CkPublicKeyW.h>
#include <C_CkJwtW.h>
#include <C_CkJweW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkJsonObjectW json;
    HCkPublicKeyW pubkey;
    HCkJwtW jwt;
    HCkJsonObjectW jweProtHdr;
    HCkJweW jwe;
    const wchar_t *plainText;
    const wchar_t *strJwe;

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

    // Load our brainpool BP-256 public key.

    // 	{
    // 	  "use": "enc",
    // 	  "kid": "puk_idp_enc",
    // 	  "kty": "EC",
    // 	  "crv": "BP-256",
    // 	  "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w",
    // 	  "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
    // 	}

    json = CkJsonObjectW_Create();
    CkJsonObjectW_UpdateString(json,L"use",L"enc");
    CkJsonObjectW_UpdateString(json,L"kid",L"puk_idp_enc");
    CkJsonObjectW_UpdateString(json,L"kty",L"EC");
    CkJsonObjectW_UpdateString(json,L"crv",L"BP-256");
    CkJsonObjectW_UpdateString(json,L"x",L"QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w");
    CkJsonObjectW_UpdateString(json,L"y",L"AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu");

    pubkey = CkPublicKeyW_Create();

    success = CkPublicKeyW_LoadFromString(pubkey,CkJsonObjectW_emit(json));
    if (success == FALSE) {
        wprintf(L"%s\n",CkPublicKeyW_lastErrorText(pubkey));
        CkJsonObjectW_Dispose(json);
        CkPublicKeyW_Dispose(pubkey);
        return;
    }

    // Build our protected header:

    // 	{
    // 	  "alg": "ECDH-ES",
    // 	  "enc": "A256GCM",
    // 	  "exp": 1621957030,
    // 	  "cty": "NJWT",
    // 	  "epk": {
    // 	    "kty": "EC",
    // 	    "x": "QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w"
    // 	    "y": "AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu"
    // 	    "crv": "BP-256"
    // 	  }
    // 	}

    // Use jwt only for getting the current date/time + 3600 seconds.
    jwt = CkJwtW_Create();

    jweProtHdr = CkJsonObjectW_Create();
    CkJsonObjectW_UpdateString(jweProtHdr,L"alg",L"ECDH-ES");
    CkJsonObjectW_UpdateString(jweProtHdr,L"enc",L"A256GCM");
    CkJsonObjectW_UpdateInt(jweProtHdr,L"exp",CkJwtW_GenNumericDate(jwt,3600));
    CkJsonObjectW_UpdateString(jweProtHdr,L"cty",L"NJWT");
    CkJsonObjectW_UpdateString(jweProtHdr,L"epk.kty",L"EC");
    CkJsonObjectW_UpdateString(jweProtHdr,L"epk.x",L"QLpJ_LpFx-6yJhsb4OvHwU1khLnviiOwYOvmf5clK7w");
    CkJsonObjectW_UpdateString(jweProtHdr,L"epk.y",L"AJh7pJ3zZKDJkm8rbeG69GBooTosXJgSsvNFH0i3Vxnu");
    CkJsonObjectW_UpdateString(jweProtHdr,L"epk.crv",L"BP-256");

    jwe = CkJweW_Create();
    CkJweW_SetProtectedHeader(jwe,jweProtHdr);
    CkJweW_SetPublicKey(jwe,0,pubkey);

    plainText = L"This is the text to be encrypted.";
    strJwe = CkJweW_encrypt(jwe,plainText,L"utf-8");
    if (CkJweW_getLastMethodSuccess(jwe) != TRUE) {
        wprintf(L"%s\n",CkJweW_lastErrorText(jwe));
        CkJsonObjectW_Dispose(json);
        CkPublicKeyW_Dispose(pubkey);
        CkJwtW_Dispose(jwt);
        CkJsonObjectW_Dispose(jweProtHdr);
        CkJweW_Dispose(jwe);
        return;
    }

    wprintf(L"%s\n",strJwe);

    wprintf(L"Success.\n");


    CkJsonObjectW_Dispose(json);
    CkPublicKeyW_Dispose(pubkey);
    CkJwtW_Dispose(jwt);
    CkJsonObjectW_Dispose(jweProtHdr);
    CkJweW_Dispose(jwe);

    }