Unicode C Requires Chilkat v11.7.0+
Unicode C
Choose the PDF Encryption Algorithm: AES-256, AES-128 or RC4
See more PDF Protection Examples
Demonstrates the algorithmChoice option of the encrypt operation. aes-256 is the default and the one to use unless an older reader must open the file. aes-128 is for readers that predate AES-256. rc4-128 and rc4-40 are broken ciphers kept only for very old readers. Each algorithm needs a minimum PDF version, and the file header is raised to it when the PDF is saved, never lowered. A PDF saved with RC4 is written with a classic cross-reference table so that those old readers can parse it.Chilkat Unicode C Downloads
#include <C_CkJsonObjectW.h>
#include <C_CkPdfW.h>
void ChilkatSample(void)
{
BOOL success;
HCkJsonObjectW json;
HCkJsonObjectW jsonOut;
HCkJsonObjectW info;
HCkPdfW pdf1;
HCkPdfW pdf2;
HCkPdfW pdf3;
success = FALSE;
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
// The PDF used in this example is available at two_page_memo.pdf
json = CkJsonObjectW_Create();
jsonOut = CkJsonObjectW_Create();
info = CkJsonObjectW_Create();
// AES-256, the default. Saved as PDF 1.7 with Adobe extension level 8.
pdf1 = CkPdfW_Create();
success = CkPdfW_LoadFile(pdf1,L"qa_data/pdf/two_page_memo.pdf");
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf1));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
return;
}
CkPdfW_putUserPassword(pdf1,L"user-secret");
CkPdfW_putOwnerPassword(pdf1,L"owner-secret");
CkJsonObjectW_UpdateString(json,L"algorithmChoice",L"aes-256");
success = CkPdfW_Protection(pdf1,L"encrypt",json,jsonOut);
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf1));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
return;
}
wprintf(L"aes-256 will be saved as PDF %s, Adobe extension level %d\n",CkJsonObjectW_stringOf(jsonOut,L"pending.pdfVersion"),CkJsonObjectW_IntOf(jsonOut,L"pending.adobeExtensionLevel"));
success = CkPdfW_WriteFile(pdf1,L"qa_output/memo_aes256.pdf");
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf1));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
return;
}
success = CkPdfW_PreLoadCheck(pdf1,L"qa_output/memo_aes256.pdf",info);
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf1));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
return;
}
wprintf(L" saved file: %s, PDF %s\n",CkJsonObjectW_stringOf(info,L"algorithm"),CkJsonObjectW_stringOf(info,L"pdfVersion"));
// AES-128, for readers that predate AES-256. Saved as PDF 1.6.
pdf2 = CkPdfW_Create();
success = CkPdfW_LoadFile(pdf2,L"qa_data/pdf/two_page_memo.pdf");
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf2));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
CkPdfW_Dispose(pdf2);
return;
}
CkPdfW_putUserPassword(pdf2,L"user-secret");
CkPdfW_putOwnerPassword(pdf2,L"owner-secret");
CkJsonObjectW_UpdateString(json,L"algorithmChoice",L"aes-128");
success = CkPdfW_Protection(pdf2,L"encrypt",json,jsonOut);
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf2));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
CkPdfW_Dispose(pdf2);
return;
}
wprintf(L"aes-128 will be saved as PDF %s\n",CkJsonObjectW_stringOf(jsonOut,L"pending.pdfVersion"));
success = CkPdfW_WriteFile(pdf2,L"qa_output/memo_aes128.pdf");
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf2));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
CkPdfW_Dispose(pdf2);
return;
}
success = CkPdfW_PreLoadCheck(pdf2,L"qa_output/memo_aes128.pdf",info);
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf2));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
CkPdfW_Dispose(pdf2);
return;
}
wprintf(L" saved file: %s, PDF %s\n",CkJsonObjectW_stringOf(info,L"algorithm"),CkJsonObjectW_stringOf(info,L"pdfVersion"));
// RC4-128, a broken cipher, only for readers too old for AES. Saved as PDF 1.4.
pdf3 = CkPdfW_Create();
success = CkPdfW_LoadFile(pdf3,L"qa_data/pdf/two_page_memo.pdf");
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf3));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
CkPdfW_Dispose(pdf2);
CkPdfW_Dispose(pdf3);
return;
}
CkPdfW_putUserPassword(pdf3,L"user-secret");
CkPdfW_putOwnerPassword(pdf3,L"owner-secret");
CkJsonObjectW_UpdateString(json,L"algorithmChoice",L"rc4-128");
success = CkPdfW_Protection(pdf3,L"encrypt",json,jsonOut);
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf3));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
CkPdfW_Dispose(pdf2);
CkPdfW_Dispose(pdf3);
return;
}
wprintf(L"rc4-128 will be saved as PDF %s\n",CkJsonObjectW_stringOf(jsonOut,L"pending.pdfVersion"));
success = CkPdfW_WriteFile(pdf3,L"qa_output/memo_rc4_128.pdf");
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf3));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
CkPdfW_Dispose(pdf2);
CkPdfW_Dispose(pdf3);
return;
}
success = CkPdfW_PreLoadCheck(pdf3,L"qa_output/memo_rc4_128.pdf",info);
if (success == FALSE) {
wprintf(L"%s\n",CkPdfW_lastErrorText(pdf3));
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
CkPdfW_Dispose(pdf2);
CkPdfW_Dispose(pdf3);
return;
}
wprintf(L" saved file: %s, PDF %s\n",CkJsonObjectW_stringOf(info,L"algorithm"),CkJsonObjectW_stringOf(info,L"pdfVersion"));
// Sample output:
// aes-256 will be saved as PDF 1.7, Adobe extension level 8
// saved file: aes-256, PDF 1.7
// aes-128 will be saved as PDF 1.6
// saved file: aes-128, PDF 1.6
// rc4-128 will be saved as PDF 1.4
// saved file: rc4-128, PDF 1.4
CkJsonObjectW_Dispose(json);
CkJsonObjectW_Dispose(jsonOut);
CkJsonObjectW_Dispose(info);
CkPdfW_Dispose(pdf1);
CkPdfW_Dispose(pdf2);
CkPdfW_Dispose(pdf3);
}