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

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

    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.

    plaintext = L"Live long and prosper.";

    jwe = CkJweW_Create();

    // First build the JWE Protected Header: {"alg":"A128KW","enc":"A128CBC-HS256"}
    jweProtHdr = CkJsonObjectW_Create();
    CkJsonObjectW_AppendString(jweProtHdr,L"alg",L"A128KW");
    CkJsonObjectW_AppendString(jweProtHdr,L"enc",L"A128CBC-HS256");
    CkJweW_SetProtectedHeader(jwe,jweProtHdr);

    wprintf(L"JWE Protected Header: %s\n",CkJsonObjectW_emit(jweProtHdr));
    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:
    aesWrappingKey = L"GawgguFyGrWKav7AX4VKUg";
    CkJweW_SetWrappingKey(jwe,0,aesWrappingKey,L"base64url");

    // 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);
        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);
        CkJweW_Dispose(jwe2);
        return;
    }

    // Set the AES wrap key.
    CkJweW_SetWrappingKey(jwe2,0,aesWrappingKey,L"base64url");

    // 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);
        CkJweW_Dispose(jwe2);
        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.

    sbJwe = CkStringBuilderW_Create();
    CkStringBuilderW_Append(sbJwe,L"eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.");
    CkStringBuilderW_Append(sbJwe,L"6KB707dM9YTIgHtLvtgWQ8mKwboJW3of9locizkDTHzBC2IlrT1oOQ.");
    CkStringBuilderW_Append(sbJwe,L"AxY8DCtDaGlsbGljb3RoZQ.");
    CkStringBuilderW_Append(sbJwe,L"KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY.");
    CkStringBuilderW_Append(sbJwe,L"U0m_YmjN04DJvceFICbCVQ");

    success = CkJweW_LoadJweSb(jwe2,sbJwe);
    if (success != TRUE) {
        wprintf(L"%s\n",CkJweW_lastErrorText(jwe2));
        CkJweW_Dispose(jwe);
        CkJsonObjectW_Dispose(jweProtHdr);
        CkJweW_Dispose(jwe2);
        CkStringBuilderW_Dispose(sbJwe);
        return;
    }

    CkJweW_SetWrappingKey(jwe2,0,aesWrappingKey,L"base64url");

    // 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);
        CkJweW_Dispose(jwe2);
        CkStringBuilderW_Dispose(sbJwe);
        return;
    }

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


    CkJweW_Dispose(jwe);
    CkJsonObjectW_Dispose(jweProtHdr);
    CkJweW_Dispose(jwe2);
    CkStringBuilderW_Dispose(sbJwe);

    }