Chapter 5 (part 1) include objectives: Explain general cryptography concepts, explain basic hashing concepts, basic encryption concepts, explain and implement protocols, explain core concepts of public key cryptography. | Cryptography Basics Objectives Explain general cryptography concepts Explain basic hashing concepts. Basic encryption concepts. Explain and implement protocols Explain core concepts of public key cryptography Cryptography Cryptography – science of encrypting information. “scrambles” (xáo trộn) data so only authorized parties can “unscramble” and read data using two methods Can substitute – change one letter with a different letter (thay thế) Can transpose – scramble the order of letters, without actually changing one for another. (chuyển vị) The best cryptosystems both substitute and transpose. Basic Idea Cryptographic Terminology Cryptography - a method of storing and transmitting data in a form only intended for authorized parties to read or process. Cryptanalysis (phân tích mật mã) - science of studying, breaking, and reverse engineering algorithms and keys. Encryption (mã hóa)– the method of transforming data (plaintext) into an unreadable format. Plain text (cleartext): dữ liệu gốc – the format (usually readable) of data before being encrypted Cipher text (dữ liệu đã được mã hóa) – the “Scrambled” format of data after being encrypted Cryptographic Terminology Decryption (giải mã) – the method of turning cipher text back into plain text Encryption algorithm – a set or rules or procedures that dictates how to encrypt and decrypt data. Also called an encryption “cipher” Key – (crypto variable) a values used in the encryption process to encrypt and decrypt Cryptographic Terminology Key space (không gian khóa) – the range of possible values used to construct keys example: if a key can be 4 digits (0-9) key space = 10,000 (0000 – 9999) if it can be 6 digits key space = 1,000,000 (000,000 – 999,999) Key Clustering – Instance when two different keys generate the same cipher text from the same plaintext Work factor – estimated time and resources to break a cryptosystem Các mục tiêu của mã hóa confidentiality/privacy (Tính bí mật) Integrity (Tính toàn vẹn) . | Cryptography Basics Objectives Explain general cryptography concepts Explain basic hashing concepts. Basic encryption concepts. Explain and implement protocols Explain core concepts of public key cryptography Cryptography Cryptography – science of encrypting information. “scrambles” (xáo trộn) data so only authorized parties can “unscramble” and read data using two methods Can substitute – change one letter with a different letter (thay thế) Can transpose – scramble the order of letters, without actually changing one for another. (chuyển vị) The best cryptosystems both substitute and transpose. Basic Idea Cryptographic Terminology Cryptography - a method of storing and transmitting data in a form only intended for authorized parties to read or process. Cryptanalysis (phân tích mật mã) - science of studying, breaking, and reverse engineering algorithms and keys. Encryption (mã hóa)– the method of transforming data (plaintext) into an unreadable format. Plain text (cleartext): dữ liệu .
