Old books available in (English)

*Cryptography and Network Security* by William Stallings is a comprehensive textbook that provides an in-depth introduction to the fields of cryptography and network security. The book covers a wide range of topics essential for understanding secure communications, including classical encryption techniques, public-key cryptography, cryptographic protocols, and the application of cryptography in network security. The text is divided into several key sections, focusing on foundational principles, algorithms, and protocols for securing networks.