re des salts in article mar demax com mikel demax com mikel lechner writes you could just as well use a character password to perform the encryption of the zero bits one simple method would be to use the first characters to encrypt the zero bits and then use the remaining characters to encrypt the result again the output would still be bits which encodes into ascii characters wouldn t this method be vulnerable against a birthday attack currently a cracker needs to find the only key that produces the given ciphertext he has to try about keys on the average in the proposed method the cracker only needs any pair of key halves if he can store about guesses for one half he is likely to find a mathching pair in about guesses here i have assumed that the des encryption is reversable if the key is guessed is this so or do the modifications of the s boxes by the salt bits make it non reversable probably there is only one key i think there is chance in about that there are two or more keys can anyone verify this but this doesn t help the cracker much
