Cryptanalysis techniques are methods used to break or analyze cryptographic systems, aiming to uncover hidden information without access to the secret key. These techniques can involve various approaches, such as frequency analysis, which examines the frequency of letters or symbols in a ciphertext, or brute force attacks, where every possible key is tested until the correct one is found. Another common technique is known as differential cryptanalysis, which studies how differences in input can affect the resultant output in a cryptographic algorithm. Additionally, linear cryptanalysis uses linear approximations to describe the relationship between plaintext, ciphertext, and key bits, helping to reveal the key more efficiently.