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C++

Set JWE Additional Authenticated Data

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.SetAad, which sets external Additional Authenticated Data (AAD) for a JWE being encrypted, encoding the supplied text with the given charset.

Background. AAD is integrity-protected but not encrypted, binding external context to the ciphertext. The same AAD must be supplied again when decrypting.

Chilkat C++ Downloads

C++
#include <CkJwe.h>
#include <CkJsonObject.h>
#include <CkStringBuilder.h>

void ChilkatSample(void)
    {
    bool success = false;

    CkJwe jwe;

    //  Protected header: AES key-wrap with AES-256-GCM content encryption.
    CkJsonObject header;
    header.UpdateString("alg","A256KW");
    header.UpdateString("enc","A256GCM");
    success = jwe.SetProtectedHeader(header);
    if (success == false) {
        std::cout << jwe.lastErrorText() << "\r\n";
        return;
    }

    //  The 256-bit key-wrapping key (base64) for recipient index 0.  In production, obtain the key from a
    //  secure source rather than hard-coding it.
    const char *base64Key = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=";
    success = jwe.SetWrappingKey(0,base64Key,"base64");
    if (success == false) {
        std::cout << jwe.lastErrorText() << "\r\n";
        return;
    }

    //  Set external Additional Authenticated Data (AAD).  The AAD is integrity-protected but not
    //  encrypted, and must be supplied again when decrypting.
    success = jwe.SetAad("context-info-v1","utf-8");
    if (success == false) {
        std::cout << jwe.lastErrorText() << "\r\n";
        return;
    }

    CkStringBuilder sbContent;
    sbContent.Append("This is the secret content.");
    CkStringBuilder sbJwe;
    success = jwe.EncryptSb(sbContent,"utf-8",sbJwe);
    if (success == false) {
        std::cout << jwe.lastErrorText() << "\r\n";
        return;
    }

    std::cout << sbJwe.getAsString() << "\r\n";
    }