MelissaA
Brenton
Shilpa Karhik
A bluffer's guide to cryptanalysis
July 17th 2006 03:58
Today's post is a follow up from my previous post and is a bluffer's guide to cryptanalysis (or codebreaking). Once again it is going to be quite short, so if you want any more detail then feel free to request it.
What is cryptanalysis?
Cryptanalysis aims to break codes without gaining access to secret information as such as they key or encryption algorithm.
Methods of cryptanalysis
Historically, the main method of cryptanalysis was the use of frequency analysis, which used the fact that in most languages certain letters are more common, to decipher plaintext from cyphertext.
In today's world this method of cryptanalysis generally fails and even when a person possesses both the ciphertext and a plaintext translation it is impossible for them to find out the key used to encode the message. Modern cryptanalysis aims to decrypting weak methods of encryption and in developing the complex mathematics required to find a way to crack public key encryption.
There are a few methods of cryptoanalysis and these differ based on what is known about the plaintext, ciphertext and key. For example, a ciphertext only attack is when the codebreaker has access only to ciphertext and a known-plaintext attack, where the attacker knows both the ciphertext and equivalent plaintext.
Attacks on asymmetrical ciphers are very different. These ciphers are encoded based on a reliance on mathematical problems that are hard to computer. Attempts to break these code aim to solve the mathematical problems that are used to encode the keys and in this sense work very differently.
What is cryptanalysis?
Cryptanalysis aims to break codes without gaining access to secret information as such as they key or encryption algorithm.
Methods of cryptanalysis
Historically, the main method of cryptanalysis was the use of frequency analysis, which used the fact that in most languages certain letters are more common, to decipher plaintext from cyphertext.
In today's world this method of cryptanalysis generally fails and even when a person possesses both the ciphertext and a plaintext translation it is impossible for them to find out the key used to encode the message. Modern cryptanalysis aims to decrypting weak methods of encryption and in developing the complex mathematics required to find a way to crack public key encryption.
There are a few methods of cryptoanalysis and these differ based on what is known about the plaintext, ciphertext and key. For example, a ciphertext only attack is when the codebreaker has access only to ciphertext and a known-plaintext attack, where the attacker knows both the ciphertext and equivalent plaintext.
Attacks on asymmetrical ciphers are very different. These ciphers are encoded based on a reliance on mathematical problems that are hard to computer. Attempts to break these code aim to solve the mathematical problems that are used to encode the keys and in this sense work very differently.
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