Chapter 2 Crypto Basics Flashcards
what is cryptology
the art and science of making and breaking “secret codes”
what is cryptography
MAKING secret codes
what is cryptanalysis
BREAKING secret codes
what is the result of an encryption
cipher-text
what is used to configure a crypto-system
a key
what is a symmetric key
a cryptosystem that uses the same key to encrypt as to decrypt
what is a public key
a cryptosystem that uses a public key to encrypt and a private key to decrypt
what is kerckhoffs principle
the system is completely known to the attacker, only the key is secret, that is crypto algorithms are not secret
why do we make assumptions in kerckhoffs principle
experience has shown that secret algorithms are weak when exposed, secret algorithms never remain secret, better to find weaknesses before hand
The picture of crypto as a black box is aslo called
symmetric key crypto
in the symmetric key crypto what can trudy see
the encrypt, the decrypt, some of the plain text but not the key
for simple substitution the shift is called
caesars cipher
when trying all possibilities it is called
exhaustive key search
In general simple substitution key can be any ________ of letters
permutation, 26! > 2^88
what is secure cryptanalysis
cryptosystem is secure if best know attack is to try all keys
