C

Example for both AES-128 and ChaCha20 to Encrypt Binary Data

See more Encryption Examples

Demonstrates the use of the new EncryptBd and DecryptBd methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt binary bytes.

Note: This example requires Chilkat v9.5.0.67 or greater.

C

#include <C_CkBinData.h>
#include <C_CkCrypt2.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkBinData jpgBytes;
    HCkCrypt2 crypt;
    const char *ivHex;
    const char *keyHex;

    success = FALSE;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // Load a small JPG file to be encrypted/decrypted.
    jpgBytes = CkBinData_Create();
    success = CkBinData_LoadFile(jpgBytes,"qa_data/jpg/starfish.jpg");
    if (success != TRUE) {
        printf("Failed to load JPG file.\n");
        CkBinData_Dispose(jpgBytes);
        return;
    }

    // Show the unencrypted JPG bytes in Base64 format.
    // (The "base64_mime" encoding was added in Chilkat v9.5.0.67.
    // The "base64" encoding emits a single line of base64, whereas
    // "base64_mime" will emit multi-line base64 as it would appear
    // in MIME.)
    printf("%s\n",CkBinData_getEncoded(jpgBytes,"base64_mime"));

    // Sample base64_mime JPG data:

    // 	/9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA
    // 	AQBIAAAAAQABOEJJTQPzAAAAAAAIAAAAAAAAAAE4QklNBAoAAAAAAAEAADhCSU0nEAAAAAAACgAB
    // 	AAAAAAAAAAI4QklNA/UAAAAAAEgAL2ZmAAEAbGZmAAYAAAAAAAEAL2ZmAAEAoZmaAAYAAAAAAAEA
    // 	MgAAAAEAWgAAAAYAAAAAAAEANQAAAAEALQAAAAYAAAAAAAE4QklNBBQAAAAAAAQAAAABOEJJTQQM
    // 	...

    crypt = CkCrypt2_Create();

    // Specify the encryption to be used.
    // First we'll do AES-128 CBC
    CkCrypt2_putCryptAlgorithm(crypt,"aes");
    CkCrypt2_putCipherMode(crypt,"cbc");
    CkCrypt2_putKeyLength(crypt,128);

    ivHex = "000102030405060708090A0B0C0D0E0F";
    CkCrypt2_SetEncodedIV(crypt,ivHex,"hex");

    keyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F";
    CkCrypt2_SetEncodedKey(crypt,keyHex,"hex");

    // Do the in-place 128-bit AES CBC encryption.
    // The contents of jpgBytes are replaced with the encrypted bytes.
    success = CkCrypt2_EncryptBd(crypt,jpgBytes);
    if (success != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkBinData_Dispose(jpgBytes);
        CkCrypt2_Dispose(crypt);
        return;
    }

    // Examine the JPG bytes again.  The bytes should be different because they are encrypted:
    printf("%s\n",CkBinData_getEncoded(jpgBytes,"base64_mime"));

    // Sample base64_mime encrypted JPG data:

    // 	sbz0babt1WCkQf5xKMdg/baZAcUBO5GVUUDF2BjVqmd+HrqKN+t6hAcqakL/bdo0q9hYmow0Tp1e
    // 	AQ9V9DOiifQUZqWVkR+kL/c45bq8JGFDvgNl0djPt+yYhV789IB/fPH0upx+/ad++WNOlv1IxGMr
    // 	Y1x1oERU/IsiEzafUJdI4kZ6FQo2IPGMF/Rm1h79I7hP1yYUFxvJyz+PzaySAUH1nLsNHyDVY5VY
    // 	O90aH3steRSYbz8C8UF9wQ3qqEIXQNnnixvoNDnmHyY39VoVBI5F6rnPwYDfAk2t8tmuryFqvwAu
    // 	...

    // Decrypt to restore back to the original:
    success = CkCrypt2_DecryptBd(crypt,jpgBytes);
    if (success != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkBinData_Dispose(jpgBytes);
        CkCrypt2_Dispose(crypt);
        return;
    }

    printf("%s\n",CkBinData_getEncoded(jpgBytes,"base64_mime"));

    // 	/9j/4AAQSkZJRgABAgEASABIAAD/7Q18UGhvdG9zaG9wIDMuMAA4QklNA+0AAAAAABAASAAAAAEA
    // 	AQBIAAAAAQABOEJJTQPzAAAAAAAIAAAAAAAAAAE4QklNBAoAAAAAAAEAADhCSU0nEAAAAAAACgAB
    // 	AAAAAAAAAAI4QklNA/UAAAAAAEgAL2ZmAAEAbGZmAAYAAAAAAAEAL2ZmAAEAoZmaAAYAAAAAAAEA
    // 	MgAAAAEAWgAAAAYAAAAAAAEANQAAAAEALQAAAAYAAAAAAAE4QklNBBQAAAAAAAQAAAABOEJJTQQM
    // 	...

    // ----------------------------------------------------------------------------------
    // To do chacha20 encryption, just change the settings:

    CkCrypt2_putCryptAlgorithm(crypt,"chacha20");
    CkCrypt2_putKeyLength(crypt,256);
    // The initial count is the initial block counter for the chacha20 algorithm.
    // It can be any integer, but must be set to the same when decrypting.
    CkCrypt2_putInitialCount(crypt,22);

    success = CkCrypt2_EncryptBd(crypt,jpgBytes);
    // jpgBytes now contains chacha20 encrypted bytes.

    success = CkCrypt2_DecryptBd(crypt,jpgBytes);
    // jpgBytes is now restored back to the original unencrypted by bytes.

    // Save the bytes to a file..
    success = CkBinData_WriteFile(jpgBytes,"qa_output/starfish.jpg");

    printf("Success.\n");


    CkBinData_Dispose(jpgBytes);
    CkCrypt2_Dispose(crypt);

    }