ChaCha and Salsa ciphers have undergone extensive cryptanalysis, revealing vulnerabilities in low-round versions, particularly against differential cryptanalysis. Although higher-round variants mitigate these issues, their computational complexity raises concerns. This chapter examines nonce expansion strategies for ChaCha and Salsa, including XChaCha and XSalsa, which extend nonce lengths without compromising counter efficiency. A new extension, eChaCha, is also introduced, which integrates an external random number generator to refine state matrix differentiation. This enhancement improves key and IV mixing, reinforcing security while maintaining performance efficiency.