C

AES and CHACHA20 Encrypt/Decrypt Text

See more Encryption Examples

Demonstrates the use of the new EncryptSb and DecryptSb methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt the contents of StringBuilder objects.

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

C

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

void ChilkatSample(void)
    {
    BOOL success;
    HCkStringBuilder sb;
    int i;
    HCkCrypt2 crypt;
    const char *ivHex;
    const char *keyHex;
    HCkBinData bdEncrypted;
    HCkStringBuilder sbOriginal;

    success = FALSE;

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

    // First build a string to be encrypted
    sb = CkStringBuilder_Create();
    i = 1;
    while (i < 10) {
        CkStringBuilder_AppendInt(sb,i);
        CkStringBuilder_Append(sb," the quick brown fox jumped over the lazy dog.\r\n");
        i = i + 1;
    }

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

    // The string to be encrypted looks like this:

    // 1 the quick brown fox jumped over the lazy dog.
    // 2 the quick brown fox jumped over the lazy dog.
    // 3 the quick brown fox jumped over the lazy dog.
    // 4 the quick brown fox jumped over the lazy dog.
    // 5 the quick brown fox jumped over the lazy dog.
    // 6 the quick brown fox jumped over the lazy dog.
    // ...

    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");

    // When EncryptSb is called, the contents of the source (sb)
    // remains unmodified.  The encrypted bytes are written into bdEncrypted.
    // If bdEncrypted already contained data, it is replaced with the encrypted bytes.
    bdEncrypted = CkBinData_Create();
    success = CkCrypt2_EncryptSb(crypt,sb,bdEncrypted);
    if (success != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkStringBuilder_Dispose(sb);
        CkCrypt2_Dispose(crypt);
        CkBinData_Dispose(bdEncrypted);
        return;
    }

    // Examine the encrypted bytes:
    printf("%s\n",CkBinData_getEncoded(bdEncrypted,"base64_mime"));

    // Sample encrypted data:

    // 0DdNZ22ckMMJBiaKhAu3wUEfh16XW356NIUsDmNs/xwbHe/p1201OmpfzwXwKktkAefu2pckrBgC
    // df+1w8lRo+KAy5n5wlAgMGM/UrsVJsp0BmDPk1vaxKrmrGpSXOVCQs1n2+0atIs5YLiOG+Va3+Mi
    // EQNb4YK7bNMmvt0++irBxTiGnkx/RncfKwgkbBUpl2x7yV13MW6lapDT6Md0DKAMsTXFJYGeIdEf
    // g2uxDDQzI5gUOUHTMrXQ8paD/K76KKB9Jpp/kAM9z8g/d8KUmuphA7KI64d38xsgOmcITlbhlCQ2
    // PDkcU6RRzX0FUTUSMgQukhy0jkLZEjHX9poKJD+iJTOkcQUC3OqR9hKhSrvIgJN4lxdR71MheOoQ
    // 2wmvRdq+agTWWh333Vmb6J6yDV79aSpnqEDrA8Ks7Xzciol0gve91+JtVJlJKjWwEzWEU8GxF7Q8
    // eaWI70lsC5nTLGcbqgKu6gzkzHlHyHaE2FAQA/d5I2dvfsAYUQCza0Zdyw8mmTtHhlP2Tfxj1uPv
    // H4Q7BGuKnx3SWT2CnpbX4091w7KzLAztrbFBo/Tf9w8ZpgTK9k1ryfW9/xnk6rW6iQ==

    // Decrypt to restore back to the original:
    sbOriginal = CkStringBuilder_Create();
    success = CkCrypt2_DecryptSb(crypt,bdEncrypted,sbOriginal);
    if (success != TRUE) {
        printf("%s\n",CkCrypt2_lastErrorText(crypt));
        CkStringBuilder_Dispose(sb);
        CkCrypt2_Dispose(crypt);
        CkBinData_Dispose(bdEncrypted);
        CkStringBuilder_Dispose(sbOriginal);
        return;
    }

    // Examine the original data:
    printf("%s\n",CkStringBuilder_getAsString(sbOriginal));

    // ----------------------------------------------------------------------------------
    // 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);

    // EncryptSb completely replaces the contents of bdEncrypted.
    success = CkCrypt2_EncryptSb(crypt,sb,bdEncrypted);

    // However.. DecryptSb appends the decrypted text to whatever may
    // have already existed within sbOriginal.
    success = CkCrypt2_DecryptSb(crypt,bdEncrypted,sbOriginal);

    printf("----\n");
    printf("The original data should be here twice.  Once from the AES decrypt, and again from the chacha20 decrypt.\n");
    printf("%s\n",CkStringBuilder_getAsString(sbOriginal));
    printf("Success.\n");


    CkStringBuilder_Dispose(sb);
    CkCrypt2_Dispose(crypt);
    CkBinData_Dispose(bdEncrypted);
    CkStringBuilder_Dispose(sbOriginal);

    }