(Unicode C++) JWE using A256GCMKW

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

Chilkat C/C++ Library Downloads
MS Visual C/C++ Linux/CentOS C/C++ Alpine Linux C/C++ MAC OS X C/C++	armhf/aarch64 C/C++ C++ Builder iOS C/C++ Android C/C++	Solaris C/C++ MinGW C/C++

#include <CkJweW.h>
#include <CkJsonObjectW.h>
#include <CkPrngW.h>

void ChilkatSample(void)
    {
    // This requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    bool success;
    const wchar_t *plaintext = L"My text to enrypt";

    CkJweW jwe;

    // First build the JWE Protected Header: 

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

    CkJsonObjectW jweProtHdr;
    jweProtHdr.AppendString(L"alg",L"A256GCMKW");
    // kid is optional
    jweProtHdr.AppendString(L"kid",L"18ec08e1-bfa9-4d95-b205-2b4dd1d4321d");
    // tag is optional
    jweProtHdr.AppendString(L"tag",L"kfPduVQ3T3H6vnewt--ksw");
    jweProtHdr.AppendString(L"enc",L"A256GCM");
    // the iv should be 16 random chars.
    CkPrngW prng;
    jweProtHdr.AppendString(L"iv",prng.randomString(16,true,true,true));
    jwe.SetProtectedHeader(jweProtHdr);

    wprintf(L"JWE Protected Header: %s\n",jweProtHdr.emit());
    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.
    const wchar_t *aesWrappingKey = L"2baf4f730f5e4542b428593ef9cceb0e";
    jwe.SetWrappingKey(0,aesWrappingKey,L"ascii");

    // Encrypt and return the JWE:
    const wchar_t *strJwe = jwe.encrypt(plaintext,L"utf-8");
    if (jwe.get_LastMethodSuccess() != true) {
        wprintf(L"%s\n",jwe.lastErrorText());
        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.
    CkJweW jwe2;
    success = jwe2.LoadJwe(strJwe);
    if (success != true) {
        wprintf(L"%s\n",jwe2.lastErrorText());
        return;
    }

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

    // Decrypt.
    const wchar_t *originalPlaintext = jwe2.decrypt(0,L"utf-8");
    if (jwe2.get_LastMethodSuccess() != true) {
        wprintf(L"%s\n",jwe2.lastErrorText());
        return;
    }

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