Unicode C

JWE using A256GCMKW

See more JSON Web Encryption (JWE) Examples

This example demonstrates creating a JCE with AES GCM key wrap. Unicode C

#include <C_CkJweW.h>
#include <C_CkJsonObjectW.h>
#include <C_CkPrngW.h>

void ChilkatSample(void)
    {
    BOOL success;
    const wchar_t *plaintext;
    HCkJweW jwe;
    HCkJsonObjectW jweProtHdr;
    HCkPrngW prng;
    const wchar_t *aesWrappingKey;
    const wchar_t *strJwe;
    HCkJweW jwe2;
    const wchar_t *originalPlaintext;

    success = FALSE;

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

    plaintext = L"My text to enrypt";

    jwe = CkJweW_Create();

    // First build the JWE Protected Header: 

    //         {
    //             "alg": "A256GCMKW",
    //             "kid": "18ec08e1-bfa9-4d95-b205-2b4dd1d4321d",
    //             "tag": "kfPduVQ3T3H6vnewt--ksw",
    //             "iv": "KkYT0GX_2jHlfqN_",
    //             "enc": "A128CBC-HS256"
    //         }

    jweProtHdr = CkJsonObjectW_Create();
    CkJsonObjectW_AppendString(jweProtHdr,L"alg",L"A256GCMKW");
    // kid is optional
    CkJsonObjectW_AppendString(jweProtHdr,L"kid",L"18ec08e1-bfa9-4d95-b205-2b4dd1d4321d");
    // tag is optional
    CkJsonObjectW_AppendString(jweProtHdr,L"tag",L"kfPduVQ3T3H6vnewt--ksw");
    CkJsonObjectW_AppendString(jweProtHdr,L"enc",L"A256GCM");
    // the iv should be 16 random chars.
    prng = CkPrngW_Create();
    CkJsonObjectW_AppendString(jweProtHdr,L"iv",CkPrngW_randomString(prng,16,TRUE,TRUE,TRUE));
    CkJweW_SetProtectedHeader(jwe,jweProtHdr);

    wprintf(L"JWE Protected Header: %s\n",CkJsonObjectW_emit(jweProtHdr));
    wprintf(L"--\n");

    // Given that we have 256-bit AES, our key should be 32 bytes.
    // The ascii string here is 32 bytes, therefore the 2nd arg is "ascii" to use these
    // ascii chars directly as the key.
    aesWrappingKey = L"2baf4f730f5e4542b428593ef9cceb0e";
    CkJweW_SetWrappingKey(jwe,0,aesWrappingKey,L"ascii");

    // Encrypt and return the JWE:
    strJwe = CkJweW_encrypt(jwe,plaintext,L"utf-8");
    if (CkJweW_getLastMethodSuccess(jwe) != TRUE) {
        wprintf(L"%s\n",CkJweW_lastErrorText(jwe));
        CkJweW_Dispose(jwe);
        CkJsonObjectW_Dispose(jweProtHdr);
        CkPrngW_Dispose(prng);
        return;
    }

    // Show the JWE we just created:
    wprintf(L"%s\n",strJwe);

    // Decrypt the JWE that was just produced.
    // 1) Load the JWE.
    // 2) Set the AES wrapping key.
    // 3) Decrypt.
    jwe2 = CkJweW_Create();
    success = CkJweW_LoadJwe(jwe2,strJwe);
    if (success != TRUE) {
        wprintf(L"%s\n",CkJweW_lastErrorText(jwe2));
        CkJweW_Dispose(jwe);
        CkJsonObjectW_Dispose(jweProtHdr);
        CkPrngW_Dispose(prng);
        CkJweW_Dispose(jwe2);
        return;
    }

    // Set the AES wrap key.  Important to use "ascii"
    CkJweW_SetWrappingKey(jwe2,0,aesWrappingKey,L"ascii");

    // Decrypt.
    originalPlaintext = CkJweW_decrypt(jwe2,0,L"utf-8");
    if (CkJweW_getLastMethodSuccess(jwe2) != TRUE) {
        wprintf(L"%s\n",CkJweW_lastErrorText(jwe2));
        CkJweW_Dispose(jwe);
        CkJsonObjectW_Dispose(jweProtHdr);
        CkPrngW_Dispose(prng);
        CkJweW_Dispose(jwe2);
        return;
    }

    wprintf(L"original text: \n");
    wprintf(L"%s\n",originalPlaintext);


    CkJweW_Dispose(jwe);
    CkJsonObjectW_Dispose(jweProtHdr);
    CkPrngW_Dispose(prng);
    CkJweW_Dispose(jwe2);

    }