A fast, highly optimized implementation of symmetric (private-key) encryption/decryption algorithms: DES, Triple DES (3DES), DESX, BLOWFISH, RIJNDAEL (AES - Advanced Encryption Standard), GOST (USSR/Russian Encryption Standard). It supports 5 modes of operation: ECB (Electronic Codebook), CBC (Cipher Block Chaining), CFB (Cipher Feedback), OFB (Output Feedback), CTR (Counter mode). The library allows to encrypt/decrypt files, memory blocks, strings, blobs, streaming data. It is quick, flexible, easy to use. It supports 2 interfaces: QuickCrypt API (the API can be used as is, or it can be used to create wrappers for languages that can use DLL or LIB), and C++ Interface (C++ wrapper classes to QuickCrypt API). It allows static/dynamic linking. It has no external dependencies such as MFC DLLs, COM/DCOM or other component. The help file has C, C++ and Visual Basic (VB) examples showing how to add encrypting/decrypting functionality to Windows applications quickly and easily.

See at http://www.slavasoft.com/quickcrypt/licenseagreement.htm