The Evolution of Cryptography Photography involves mathematical methods for ensuring confidentiality, authenticity, and integrity of information. Modern photography emerged with the advent and widespread use of computers, leading to the development of new unbreakable ciphers that rely on computer algorithms.
Understanding Ciphers A cipher is a set of reversible transformations from plaintext to ciphertext. The key parameter determines specific transformations chosen by encryptors to ensure security against adversaries.
Criteria for Modern Ciphers Modern ciphers must meet specific criteria: resistance against attacks before and after computer processing; secrecy based on key rather than algorithm; reliability in preventing disclosure even if algorithms are known or equipment is compromised.
Historical Failures in Cryptography 'Kerckhoffs' principle states that cryptographic systems should remain secure even if everything about the system except the secret keys is public knowledge.' Failure to adhere led to dramatic consequences such as weaknesses in disk encryption standards (CSS) and GSM mobile communication protection.
Key Length Requirements Cryptography requires long enough keys that make exhaustive search impractical within an acceptable time frame using available resources. This requirement stems from Kerckhoffs' principles.