Unicode C++

JWE using AES Key Wrap and AES_128_CBC_HMAC_SHA_256

See more JSON Web Encryption (JWE) Examples

This example duplicates the example A.3 in RFC 7516 for JSON Web Encryption (JWE).

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

Unicode C++

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

void ChilkatSample(void)
    {
    bool success = false;

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

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

    const wchar_t *plaintext = L"Live long and prosper.";

    CkJweW jwe;

    //  First build the JWE Protected Header: {"alg":"A128KW","enc":"A128CBC-HS256"}
    CkJsonObjectW jweProtHdr;
    jweProtHdr.AppendString(L"alg",L"A128KW");
    jweProtHdr.AppendString(L"enc",L"A128CBC-HS256");
    jwe.SetProtectedHeader(jweProtHdr);

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

    //  The example A.3 in RFC 7516 uses the following 128-bit AES key,
    //  specified in JWK (JSON Web Key) format:
    //       {"kty":"oct",
    //        "k":"GawgguFyGrWKav7AX4VKUg"
    //       }
    //  This is just a way of saying: The key type ("kty") is 
    //  a bunch of octets ("k") in base64url encoding.
    //  We can simply set the AES wrapping key like this:
    const wchar_t *aesWrappingKey = L"GawgguFyGrWKav7AX4VKUg";
    jwe.SetWrappingKey(0,aesWrappingKey,L"base64url");

    //  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.
    jwe2.SetWrappingKey(0,aesWrappingKey,L"base64url");

    //  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);

    //  ---------------------------------------------------------------------------------
    //  It should also be possible to decrypt the JWE as shown in RFC 7516, Appendix A.3.7
    //  because it was produced using the same AES Wrap key.

    CkStringBuilderW sbJwe;
    sbJwe.Append(L"eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.");
    sbJwe.Append(L"6KB707dM9YTIgHtLvtgWQ8mKwboJW3of9locizkDTHzBC2IlrT1oOQ.");
    sbJwe.Append(L"AxY8DCtDaGlsbGljb3RoZQ.");
    sbJwe.Append(L"KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY.");
    sbJwe.Append(L"U0m_YmjN04DJvceFICbCVQ");

    success = jwe2.LoadJweSb(sbJwe);
    if (success != true) {
        wprintf(L"%s\n",jwe2.lastErrorText());
        return;
    }

    jwe2.SetWrappingKey(0,aesWrappingKey,L"base64url");

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

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