Unicode C

AES 256-bit CBC using PBKDF2 Generated Secret Key

See more Encryption Examples

First generates a 32-byte secret key using PBKDF2 (with HMAC-SHA256), and then uses the secret key to do 256-bit AES CBC mode decryption.

(Duplicates the following Java code)

public String decrypt(String strToDecrypt) {
        try  {
            // Read the initialization vector from the first bytes for the data
            byte [] rawData = Base64.getDecoder().decode(strToDecrypt);
            byte [] iv = new byte[Config.get().encryptionIVLength()];
            byte [] encryptedData = new byte[rawData.length - iv.length];
            System.arraycopy(rawData, 0, iv, 0, iv.length);
            System.arraycopy(rawData, iv.length, encryptedData, 0, encryptedData.length);
 
            IvParameterSpec ivspec = new IvParameterSpec(iv);
 
            SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
            KeySpec spec = new PBEKeySpec(secretKey.toCharArray(), salt.getBytes(), 65536, 256);
            SecretKey tmp = factory.generateSecret(spec);
            SecretKeySpec secretKey = new SecretKeySpec(tmp.getEncoded(), "AES");
 
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            cipher.init(Cipher.DECRYPT_MODE, secretKey, ivspec);
            return new String(cipher.doFinal(encryptedData));
        }
        catch (Exception e) {
            log.error("Could not decrypt the string.", e);
        }
        return null;
    }

Unicode C

#include <C_CkCrypt2W.h>

void ChilkatSample(void)
    {
    HCkCrypt2W crypt;
    const wchar_t *password;
    const wchar_t *saltHex;
    int iterationCount;
    int outputKeyBitLen;
    const wchar_t *secretKeyHex;
    const wchar_t *iv;
    const wchar_t *strToDecrypt;
    const wchar_t *decryptedStr;

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

    crypt = CkCrypt2W_Create();

    password = L"some arbitrary length password";
    //  We have 8 bytes of salt encoded using hex.
    //  (The salt can be any number of bytes, in any desired encoding such as base64, hex, etc.)
    saltHex = L"0102030405060708";

    //  Generate the 256-bit (32-byte) AES secret key we'll use to decrypt.
    iterationCount = 65536;
    outputKeyBitLen = 256;
    secretKeyHex = CkCrypt2W_pbkdf2(crypt,password,L"utf-8",L"sha256",saltHex,iterationCount,outputKeyBitLen,L"hex");

    //  Setup for 256-bit AES CBC decryption.
    CkCrypt2W_putCryptAlgorithm(crypt,L"aes");
    CkCrypt2W_putKeyLength(crypt,256);
    CkCrypt2W_putCipherMode(crypt,L"cbc");
    CkCrypt2W_putPaddingScheme(crypt,0);

    //  The IV for AES is 16 bytes.
    iv = L"000102030405060708090A0B0C0D0E0F";
    CkCrypt2W_SetEncodedIV(crypt,iv,L"hex");

    //  Set the secret key for 256-bit AES.
    CkCrypt2W_SetEncodedKey(crypt,secretKeyHex,L"hex");

    //  AES decrypt
    //  assume our string to decrypt is base64
    strToDecrypt = L"....";
    CkCrypt2W_putEncodingMode(crypt,L"base64");
    decryptedStr = CkCrypt2W_decryptStringENC(crypt,strToDecrypt);

    wprintf(L"%s\n",decryptedStr);


    CkCrypt2W_Dispose(crypt);

    }