In such a system, any person can encrypt a message using the receiver's public key, but that encrypted message can only be decrypted with the receiver's private key.Q: What is differential cryptanalysis?Differential cryptanalysis is a branch of study in cryptography that compares the way differencesin input relate to the differences in encrypted output. It is used primarily in the study of block ciphers to determine if changes in plaintext result in any non-random results in the encrypted ciphertext. This process is important because when changes in the ciphertext are found to be non-random, it may signify a weakness in the encryption scheme. An unauthorized third party may beable to gain information about what was encrypted, or how it was encrypted by monitoring how the encrypted data has changed.Page 15of 24
Differential cryptanalysis seeks to find the “difference” between related plaintexts that are encrypted.Q: What is Linear Cryptanalysis? How does it differ from differential cryptanalysis?Differential cryptanalysisis a technique in which chosen plaintexts with particular XOR difference patterns are encrypted. The difference patterns of the resulting ciphertext provide information that can be used to determine the encryption key. Linear cryptanalysisis based on finding linear approximations to describe the transformations performed in a block cipher.Linear cryptanalysis is an approach where we aim to find affine approximations to the action of acipher. Letter frequency analysis is one of the simplest forms of linear cryptanalysis. Differential cryptanalysis is an approach to cryptanalysis whereby differences in inputs are mapped to differences in outputs and patterns in the mappings of plaintext edits to ciphertext variation are used to reverse engineer a keyComparison ChartLinear CryptanalysisDifferential CryptanalysisLinear cryptanalysisfirst defined by Matsui and Yamagishi in 1992.Differential cryptanalysis is a method for breaking certain classes of cryptosystemsis invented in 1990 by Israeli researchers Eli Biham and Adi Shamir.In a linear cryptanalysis the role of cryptanalyst is to identify the linear relation between some bits of the plaintext, some bits of the cipher text and somebits of the unknown key.Differential cryptanalysis is available obtain clues about some bits of the key, thereby shortening an exhaustive searchThe cryptanalyst decrypts each cipher text using all possible sub keys for one round of encryption and studies the resulting intermediate cipher text toanalyze the random result.Cryptanalyst studies changes to the intermediate cipher text obtained between multiple rounds of encryption. The attacks can be combined, which is called differential linear cryptanalysis.In a linear cryptanalysis the role of cryptanalyst is to identify the linear relation between some bits of the plaintext, some bits of the cipher text and somebits of the unknown keyBy analyzing the changes in some chosen plaintexts, and the difference in the outputs resulting from encrypting each one, it is possible to recover some of the key.