Subtitution: each letter retains its position but changes its identity, Transposition: each letter retains its identity but changes its position.
SUBSTITUTION TRANSPOSITION SUBSTITUTION & tRANSPOSITION random
A transposition cipher involves scrambling the letters in a message. The strengths of this are that there is less correspondence between characters, as there is in a substitution cipher, and that it tends to reduce redundancy.
here are three different types of ciphers. Here are a couple of examples of simple ones:Substitution Cipher: Replace bits or bytes Example - Caesarian Cipher shift up 3The enemy is nigh = Wkh hqhpb lv qljkTransposition Cipher: Example - Transposition rotate three characters rightThe enemy is nigh = ene myisn ig htheSubstitution and Transposition (modern algorithm) The enemy is nigh = hqh pblvq lj kwkh
A cryptographer would write the word "EXPLETIVE" by using a specific encryption method, such as a substitution cipher or a transposition cipher. In a substitution cipher, each letter in the word would be replaced with a different letter or symbol according to a predetermined key. In a transposition cipher, the letters in the word would be rearranged according to a specific algorithm. The resulting encrypted form of "EXPLETIVE" would be a scrambled or substituted version of the original word, making it difficult for unauthorized individuals to decipher without the key.
In a monoalphabetic cipher, our substitution characters are arandom permutation of the 26 letters of the alphabet:plaintext letters: a b c d e f .....substitution letters: t h i j a b .....• The key now is the sequence of substitution letters. In otherwords, the key in this case is the actual random permutation ofthe alphabet used.For a particular alphabet, only one substitution can be usedexample: if the substitution letter for 'a' is 't' and for 'd' it is 'p'then if the keyword happens to be "tpp"..... then we can encrypt the message as "add"(note that the substitution letter for 'd' is only 'p'..In a monoalphabetic cipher, the same substitution rule is used forevery substitution. In a polyalphabetic cipher, the substitutionrule changes continuously from letter to letter according to theelements of the encryption key.Example for polyalphabetic:key: abracadabraabracadabraabracadabraabplaintext: canyoumeetmeatmidnightihavethegoodsciphertext: CBEYQUPEFKMEBK.....................• The Vigenere cipher is an example of a polyalphabetic cipher.
In a monoalphabetic cipher, our substitution characters are a random permutation of the 26 letters of the alphabet: plaintext letters: a b c d e f ..... substitution letters: t h i j a b ..... • The key now is the sequence of substitution letters. In other words, the key in this case is the actual random permutation of the alphabet used. For a particular alphabet, only one substitution can be used example: if the substitution letter for 'a' is 't' and for 'd' it is 'p' then if the keyword happens to be "tpp"..... then we can encrypt the message as "add"(note that the substitution letter for 'd' is only 'p'.. In a monoalphabetic cipher, the same substitution rule is used for every substitution. In a polyalphabetic cipher, the substitution rule changes continuously from letter to letter according to the elements of the encryption key. Example for polyalphabetic: key: abracadabraabracadabraabracadabraab plaintext: canyoumeetmeatmidnightihavethegoods ciphertext: CBEYQUPEFKMEBK..................... • The Vigenere cipher is an example of a polyalphabetic cipher.
A transposition cipher
cipher is a lower level substitution that works at the level of the individual letters that make up the plaintext A code however is higher level and works at the level of words. Therefore this sentence could be turned into the code '@!:[]{}~+'
Caesar Cipher
mono meant one so substitution the replaced values as one character each value of alphabetic substitute A-Z . Plain text: a b c d e….. Substitution: d e f g h….. Polyalphabetic it's nothing but.. ploy meant more than one so its contain the more than one letters to substitution then also here using the key. Mono and ploy are using the same techniques of the substitution. Substitutions are having mono and ploy and then etc… In a monoalphabetic cipher, our substitution characters are a random permutation of the 26 letters of the alphabet: plaintext letters: a b c d e f ..... substitution letters: t h i j a b ..... • The key now is the sequence of substitution letters. In other words, the key in this case is the actual random permutation of the alphabet used. For a particular alphabet, only one substitution can be used example: if the substitution letter for 'a' is 't' and for 'd' it is 'p' then if the keyword happens to be "tpp"..... then we can encrypt the message as "add"(note that the substitution letter for 'd' is only 'p'.. In a monoalphabetic cipher, the same substitution rule is used for every substitution. In a polyalphabetic cipher, the substitution rule changes continuously from letter to letter according to the elements of the encryption key. Example for polyalphabetic: key: abracadabraabracadabraabracadabraab plaintext: canyoumeetmeatmidnightihavethegoods ciphertext: CBEYQUPEFKMEBK..................... • The Vigenere cipher is an example of a polyalphabetic cipher.
In a substitution cipher, each letter in the plaintext is replaced with a different letter according to a predetermined key. This key defines the mapping of each letter to its substitution, creating a one-to-one correspondence. When the recipient receives the ciphertext, they can reverse the substitution using the same key to reveal the original message.