The encryption cipher where the same letter should not be repeated for more than once in a key is O a. Rail fence ob. O c. Vigenere O d. Playfair What is the key length during the XOR operation in a DES algorithm? O a. 48 bits O b. 128 bits O c. 32 bits O d. 64 bits Identify the cryptosystem that involves multiple stages of substitutions and transpositions. O a. Cryptology O b. Transposition O c. Cryptogram O d. Product Systems A digital signature needs a(n) system O a. Asymmetric-key O b. neither Asymmetric-key or Asymmetric-key O c. either Symmetric-key or Asymmetric-key O d. Symmetric-key AES encryption and decryption are faster due to a. Smaller Block size only O b. Smaller key length O c. Smaller Key length & Smaller Block size O d. Larger Key length & Larger block size The art and science of recovering the plaintext from the encrypted message is practised by O a. Cryptographer O b. Cryptanalysts O c. Encrypter O d. Cryptology The key shift operation in a DES algorithm depends on O a. Key length O b. Left half data O c. Round number O d. Right half data The art of concealing the messages in a text O a. Cryptography O b. Text Steganography C. Substitution O d. Steganography DES uses a key generator to generate sixteen round keys. a. 48-bit O b. 64-bit unique O C. 64-bit O d. 32-bit PKC's are based on O a. Permutation O b. Substitution O c. Transposition O d. Mathematical Functions