NTRU is a public-key cryptosystem that uses polynomial rings for secure communication. It is designed to be efficient and resistant to attacks from quantum computers, making it a promising alternative to traditional cryptographic methods like RSA and ECC. The security of NTRU relies on the difficulty of solving certain mathematical problems related to lattice structures. This makes it suitable for various applications, including secure data transmission and digital signatures, while maintaining faster performance and smaller key sizes compared to other cryptographic systems.