Encrypt StringBuilder Content to a JWE

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.EncryptSb, which encrypts content supplied in a StringBuilder and writes the resulting JWE into another StringBuilder.

Background. JWE (JSON Web Encryption) protects content with a content-encryption algorithm (the header enc value) while the content-encryption key is managed by the key-management algorithm (the header alg value). This example uses AES key wrapping with a symmetric wrapping key.

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#include <C_CkJwe.h>
#include <C_CkJsonObject.h>
#include <C_CkStringBuilder.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkJwe jwe;
    HCkJsonObject header;
    const char *base64Key;
    HCkStringBuilder sbContent;
    HCkStringBuilder sbJwe;

    success = FALSE;

    jwe = CkJwe_Create();

    //  Set the JWE protected header, specifying the key-management algorithm (alg) and the content-
    //  encryption algorithm (enc).
    header = CkJsonObject_Create();
    CkJsonObject_UpdateString(header,"alg","A256KW");
    CkJsonObject_UpdateString(header,"enc","A256GCM");
    success = CkJwe_SetProtectedHeader(jwe,header);
    if (success == FALSE) {
        printf("%s\n",CkJwe_lastErrorText(jwe));
        CkJwe_Dispose(jwe);
        CkJsonObject_Dispose(header);
        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.
    base64Key = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=";
    success = CkJwe_SetWrappingKey(jwe,0,base64Key,"base64");
    if (success == FALSE) {
        printf("%s\n",CkJwe_lastErrorText(jwe));
        CkJwe_Dispose(jwe);
        CkJsonObject_Dispose(header);
        return;
    }

    //  Encrypt content supplied in a StringBuilder, writing the resulting JWE into another StringBuilder.
    sbContent = CkStringBuilder_Create();
    CkStringBuilder_Append(sbContent,"This is the secret content.");

    sbJwe = CkStringBuilder_Create();
    success = CkJwe_EncryptSb(jwe,sbContent,"utf-8",sbJwe);
    if (success == FALSE) {
        printf("%s\n",CkJwe_lastErrorText(jwe));
        CkJwe_Dispose(jwe);
        CkJsonObject_Dispose(header);
        CkStringBuilder_Dispose(sbContent);
        CkStringBuilder_Dispose(sbJwe);
        return;
    }

    printf("%s\n",CkStringBuilder_getAsString(sbJwe));


    CkJwe_Dispose(jwe);
    CkJsonObject_Dispose(header);
    CkStringBuilder_Dispose(sbContent);
    CkStringBuilder_Dispose(sbJwe);

    }