(Unicode C) JWE with DEFLATE Compression

Demonstrates how to DEFLATE ("zip") compress the JWE payload prior to encryption.

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

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

void ChilkatSample(void)
    {
    BOOL success;
    HCkStringBuilderW sbPlainText;
    BOOL bCrLf;
    const wchar_t *line;
    HCkJweW jwe;
    HCkJsonObjectW jweProtHdr;
    const wchar_t *aesWrappingKey;
    HCkStringBuilderW sbJweCompressed;
    HCkStringBuilderW sbJweUncompressed;
    HCkJweW jwe2;
    HCkStringBuilderW sbOriginalText;

    // 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.

    // Create some plaintext to be encrypted.
    // This example will demonstrate with and without DEFLATE (zip) compression.
    sbPlainText = CkStringBuilderW_Create();
    bCrLf = TRUE;
    line = L"Live long and prosper.";
    CkStringBuilderW_AppendLine(sbPlainText,line,bCrLf);
    CkStringBuilderW_AppendLine(sbPlainText,line,bCrLf);
    CkStringBuilderW_AppendLine(sbPlainText,line,bCrLf);
    CkStringBuilderW_AppendLine(sbPlainText,line,bCrLf);

    // The text to be encrypted:
    wprintf(L"%s\n",CkStringBuilderW_getAsString(sbPlainText));

    jwe = CkJweW_Create();

    // Build the JWE Protected Header: {"alg":"A128KW","enc":"A128CBC-HS256","zip":"DEF"}
    // The "zip":"DEF" parameter indicates that the plaintext payload should
    // be compressed prior to encryption.
    jweProtHdr = CkJsonObjectW_Create();
    CkJsonObjectW_AppendString(jweProtHdr,L"alg",L"A128KW");
    CkJsonObjectW_AppendString(jweProtHdr,L"enc",L"A128CBC-HS256");
    CkJsonObjectW_AppendString(jweProtHdr,L"zip",L"DEF");
    CkJweW_SetProtectedHeader(jwe,jweProtHdr);

    // Set the AES key wrap key:
    aesWrappingKey = L"GawgguFyGrWKav7AX4VKUg";
    CkJweW_SetWrappingKey(jwe,0,aesWrappingKey,L"base64url");

    // Encrypt and return the JWE in sbJweCompressed:
    sbJweCompressed = CkStringBuilderW_Create();
    success = CkJweW_EncryptSb(jwe,sbPlainText,L"utf-8",sbJweCompressed);
    if (success != TRUE) {
        wprintf(L"%s\n",CkJweW_lastErrorText(jwe));
        CkStringBuilderW_Dispose(sbPlainText);
        CkJweW_Dispose(jwe);
        CkJsonObjectW_Dispose(jweProtHdr);
        CkStringBuilderW_Dispose(sbJweCompressed);
        return;
    }

    // Show the compressed JWE:
    wprintf(L"%s\n",CkStringBuilderW_getAsString(sbJweCompressed));
    wprintf(L"size of compressed JWE: %d\n",CkStringBuilderW_getLength(sbJweCompressed));

    // Now create a JWE without compression.
    CkJsonObjectW_Delete(jweProtHdr,L"zip");
    // Make sure to update the shared protected header:
    CkJweW_SetProtectedHeader(jwe,jweProtHdr);

    sbJweUncompressed = CkStringBuilderW_Create();
    success = CkJweW_EncryptSb(jwe,sbPlainText,L"utf-8",sbJweUncompressed);
    if (success != TRUE) {
        wprintf(L"%s\n",CkJweW_lastErrorText(jwe));
        CkStringBuilderW_Dispose(sbPlainText);
        CkJweW_Dispose(jwe);
        CkJsonObjectW_Dispose(jweProtHdr);
        CkStringBuilderW_Dispose(sbJweCompressed);
        CkStringBuilderW_Dispose(sbJweUncompressed);
        return;
    }

    // Show the uncompressed JWE:
    wprintf(L"%s\n",CkStringBuilderW_getAsString(sbJweUncompressed));
    wprintf(L"size of uncompressed JWE: %d\n",CkStringBuilderW_getLength(sbJweUncompressed));

    // Decrypting is the same whether compression is used or not.
    // The "zip" header in the JWE indicates that the payload should be 
    // automatically decompressed (inflated) after decrypting.
    jwe2 = CkJweW_Create();
    success = CkJweW_LoadJweSb(jwe2,sbJweCompressed);
    if (success != TRUE) {
        wprintf(L"%s\n",CkJweW_lastErrorText(jwe2));
        CkStringBuilderW_Dispose(sbPlainText);
        CkJweW_Dispose(jwe);
        CkJsonObjectW_Dispose(jweProtHdr);
        CkStringBuilderW_Dispose(sbJweCompressed);
        CkStringBuilderW_Dispose(sbJweUncompressed);
        CkJweW_Dispose(jwe2);
        return;
    }

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

    // Decrypt (also automatically decompresses).
    sbOriginalText = CkStringBuilderW_Create();
    success = CkJweW_DecryptSb(jwe2,0,L"utf-8",sbOriginalText);
    if (success != TRUE) {
        wprintf(L"%s\n",CkJweW_lastErrorText(jwe2));
        CkStringBuilderW_Dispose(sbPlainText);
        CkJweW_Dispose(jwe);
        CkJsonObjectW_Dispose(jweProtHdr);
        CkStringBuilderW_Dispose(sbJweCompressed);
        CkStringBuilderW_Dispose(sbJweUncompressed);
        CkJweW_Dispose(jwe2);
        CkStringBuilderW_Dispose(sbOriginalText);
        return;
    }

    wprintf(L"original text from compressed JWE: \n");
    wprintf(L"%s\n",CkStringBuilderW_getAsString(sbOriginalText));

    // -----------------------------------------------------------
    // Do the same with the uncompressed JWE

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

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

    // Decrypt.
    CkStringBuilderW_Clear(sbOriginalText);
    success = CkJweW_DecryptSb(jwe2,0,L"utf-8",sbOriginalText);
    if (success != TRUE) {
        wprintf(L"%s\n",CkJweW_lastErrorText(jwe2));
        CkStringBuilderW_Dispose(sbPlainText);
        CkJweW_Dispose(jwe);
        CkJsonObjectW_Dispose(jweProtHdr);
        CkStringBuilderW_Dispose(sbJweCompressed);
        CkStringBuilderW_Dispose(sbJweUncompressed);
        CkJweW_Dispose(jwe2);
        CkStringBuilderW_Dispose(sbOriginalText);
        return;
    }

    wprintf(L"original text from uncompressed JWE: \n");
    wprintf(L"%s\n",CkStringBuilderW_getAsString(sbOriginalText));

    // ------------------------------------------------
    // The output of this example is:
    // (Note: Your output data will be different because the content encryption key is randomly generated.)

    // eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiemlwIjoiREVGIn0.xuW-pEAIdEUFnk10m8ocursvktO8Of9ByCCAt6LgKkkOtCWCUn1kQw.zpGj-9WVni3cQxyOuZbcGA.0hzP1myua3oYpUHwCIY_3edBUREbUpLaX6wYuJduOdI.Ppc6aEO3y3B8BJ1FKMPjlA
    // size of compressed JWE: 212
    // eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.N4KeyC7nnSFkieJOyE24_zKeuV_m7v5UKoJb1TgV4Yc_r2RzUPNvyA.6AEdyXSCKx-iMmUJyypSLg.QpixfyrwhGpmwUDp623viik4smPav7vwPLiC2r-V-jwnSfEH3mxWu6DbrIz3mixaqATwynmEBzVPxvS9jTXpSAGCnniib4_0WoPl3r_wF5tlsKOEe--jpNso-DKd1Tp8jJxj3JkFWt3IRnUUKGj17g.sBfDwFc5fzpaI-UW8-SW4g
    // size of uncompressed JWE: 303
    // original text from compressed JWE: 
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // 
    // original text from uncompressed JWE: 
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // 


    CkStringBuilderW_Dispose(sbPlainText);
    CkJweW_Dispose(jwe);
    CkJsonObjectW_Dispose(jweProtHdr);
    CkStringBuilderW_Dispose(sbJweCompressed);
    CkStringBuilderW_Dispose(sbJweUncompressed);
    CkJweW_Dispose(jwe2);
    CkStringBuilderW_Dispose(sbOriginalText);

    }