How to Implement AES Encryption in Visual FoxPro with MarshallSoft
Securing sensitive database records, customer text logs, and external transaction files is critical for desktop software. While Visual FoxPro (VFP) remains a reliable database engine for legacy and custom business platforms, it lacks native, modern cryptographic primitives like 256-bit AES encryption out of the box.
To bridge this gap without building a complex cryptographic wrapper from scratch, developers turn to robust, third-party libraries. The MarshallSoft Advanced Encryption Standard Library for Visual FoxPro (AES4FP) provides a lightweight, highly efficient toolkit to seamlessly run 256-bit AES (Rijndael) encryption inside all 32-bit versions of Visual FoxPro. Key Cryptographic Features of AES4FP
Strong Standards Compliance: Verified against the NIST Advanced Encryption Standard Algorithm Validation Suite (AESAVS).
Flexible Modes: Supports both ECB (Electronic Codebook) and CBC (Cipher Block Chaining) block modes.
Built-in Padding: Automatically handles PKCS7 padding for variable-length strings.
Cryptographically Secure Tools: Features a cryptographically secure pseudo-random number generator (CSPRNG) and SHA-256 hash logic.
Zero Registration Footprint: Operates as a standard Win32 DLL (aes32.dll) that requires no COM registry keys, making side-by-side deployment straightforward. Step 1: Setting Up the MarshallSoft Environment
To execute the integration, place the core library file (aes32.dll) directly within your project’s executing directory, or within your global Windows System folder (C:\Windows\SysWOW64 on a 64-bit OS). Because VFP compiles exclusively into a 32-bit binary, it must interface directly with MarshallSoft’s 32-bit execution layer.
Before invoking encryption methods, declare the target external Windows API functions at the beginning of your application code using the DECLARE - DLL directive: *— Declare Use code with caution. MarshallSoft AES Win32 API functions Use code with caution.
— DECLARE INTEGER aesInitAES IN aes32.dll ; STRING @KeyBuffer, STRING @Vector, INTEGER Mode, INTEGER Flags, STRING @Control DECLARE INTEGER aesEncryptFile IN aes32.dll ; STRING @Control, STRING @InFile, STRING @OutFile DECLARE INTEGER aesDecryptFile IN aes32.dll ; STRING @Control, STRING @InFile, STRING @OutFile— Core Constant Definitions — #DEFINE AES_ECB_MODE 0 #DEFINE AES_CBC_MODE 1 #DEFINE AES_ENCRYPT 0 #DEFINE AES_DECRYPT 1 Use code with caution. Step 2: Passing Parameters in Visual FoxPro
When interfacing with standard C-based DLLs like MarshallSoft, memory references play a critical role.