Explore fast correlation attacks over extension fields and large-unit linear approximations in cryptanalysis in this conference talk. Delve into traditional stream ciphers, the concept of fast correlation attacks, and large-unit linear approximations. Examine the SEI of a distribution and generalized pseudo-linear functions modulo 2. Learn about the complexity analysis and models for fast correlation attacks over extension fields. Investigate the SNOW 2.0 ISO/IEC 18033-4 standard stream cipher, including its byte-wise linear approximation and fast correlation attacks. Conclude with improved results, open problems, and future work in this area of cryptography.