The moreĬomplex the cipher, the larger amount of time it will take to do brute force This is easy with the caesarĬipher since there are only all the letters in the alphabet. The key and tries every single combination. * alphabet: (None): the alphabet used to decode the cipher, if notīrute force is when a person intercepts a message or password, not knowing * input_string: the cipher-text that needs to be used during brute-force Returns all the possible combinations of keys and the decoded strings in the Key *= - 1 return encrypt(input_string, key, alphabet)ĭef brute_force( input_string: str, alphabet: str | None = None) -> dict: """ # Turn on decode mode by making the key negative > decrypt('f qtbjwhfxj fqumfgjy', 5, 'abcdefghijklmnopqrstuvwxyz') 'The quick brown fox jumps over the lazy dog' > decrypt('bpm 圜qks jzwEv nwF rCuxA wDmz Bpm tiHG lwo', 8) Our final message would be "Hello, captain" The alphabet, and would become "Z" or "Y" and so on. A letter like "a" would shift back to the end of The first letter, "J" would become "H" (remember: we are decoding)īecause "H" is two letters in reverse (to the left) of "J". To decode the message, we would do the same thing as encoding, but in Please keep in mind, here we will be focused on Where very character in the plain-text is shifted by a certain number knownĪs the "key" or "shift". * A string containing the decoded plain-text * alphabet (None): the alphabet used to decode the cipher, if not * key: the number of letters to shift the message backwards by to decode * input_string: the cipher-text that needs to be decoded # Append the encoded character to the alphabetĭef decrypt( input_string: str, key: int, alphabet: str | None = None) -> str:ĭecodes a given string of cipher-text and returns the decoded plain-text New_key = (alpha.index(character) + key) % len(alpha) # Get the index of the new key and make sure it isn't too large # Append without encryption if character is not in the alphabet Result = "" for character in input_string: """ # Set default alphabet to lower and upper case english chars > encrypt('a lowercase alphabet', 5, 'abcdefghijklmnopqrstuvwxyz') 'bpm 圜qks jzwEv nwF rCuxA wDmz Bpm tiHG lwo' > encrypt('The quick brown fox jumps over the lazy dog', 8) Our final message would be "Jgnnq, ecrvckp" ("Z" would shift to "a" then "b" and so on).
Our letter is at the end of the alphabet, we just start at the beginning Since "J" is two letters away, and so on. We can then encode the message, one letter at a time. "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" Where every character in the plain-text is shifted by a certain number knownĪnd our alphabet is made up of lower and uppercase letters: The caesar cipher is named after Julius Caesar who used it when sending * A string containing the encoded cipher-text Specified, the standard english alphabet with upper and lowercase * alphabet (None): the alphabet used to encode the cipher, if not * key: the number of letters to shift the message by * input_string: the plain-text that needs to be encoded Def encrypt( input_string: str, key: int, alphabet: str | None = None) -> str:Įncodes a given string with the caesar cipher and returns the encoded
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