Solve the cipher$($image attached$).$

Hints: The ciphers will be among the following ciphers: AutoKey, Affine, Substitution, Vigenere, LFSR$,$ Permutation, Hill.

For block$-$ciphers, block length $10.$ Due to their hardness of decryption with ciphers only, for Hill cipher, $m=2$ and for LFSR$,m4.$ Particularly,

different from what is discussed in textbook, LFSR is based on $26$ rather than $2.$ That is: for key sequence $z1,z2,z3,$dots.,$yi=(+zi)$ mod $26$ and $=(yi-zi)$

mod$26,$ where $zi,,$ yi are all from $0$ to $25,$ rather than just $0$ and $1.$

Cipher text always $\{A,B,$dots,$Z\}26$ upper case letters, plain text always $\{a,b,$dots,$z\}26$ lower case letters.

Punctuation, blanks and numerals are there to help you $-$ they are not encrypted or decrypted $-$ strip punctuation, work on cipher, decipher, and

unstrip.

Keys of some ciphers, when converting from numbers $(0$ to $25)$ to letters $($a to z$),$ are meaningful English words.

For full credit,

a$)$ Decipher completely and correctly.

b$)$ Give the key and intermediate results if any.