The Vigenère cipher is a polyalphabetic substitution cipher that uses a keyword to encrypt the plaintext. To decrypt, you reverse the process.

1. Key Repetition: Write the key repeatedly above the ciphertext: KEYKEYKEYKEYKEY LXFOPVEFRNHR
2. Numerical Conversion: Convert letters to numbers (A=0, B=1... Z=25): K(10) E(4) Y(24) K(10) E(4) Y(24) K(10) E(4) Y(24) K(10) E(4) Y(24) L(11) X(23) F(5) O(15) P(14) V(21) E(4) F(5) R(17) N(13) H(7) R(17)
3. Decryption: Subtract the key number from the ciphertext number for each corresponding pair. If the result is negative, add 26 (the number of letters in the alphabet) to get a positive number within the range 0-25.
• L(11) - K(10) = 1 = B
• X(23) - E(4) = 19 = T
• F(5) - Y(24) = -19 + 26 = 7 = H
• O(15) - K(10) = 5 = F
• P(14) - E(4) = 10 = K
• V(21) - Y(24) = -3 + 26 = 23 = X
• E(4) - K(10) = -6 + 26 = 20 = U
• F(5) - E(4) = 1 = B
• R(17) - Y(24) = -7 + 26 = 19 = T
• N(13) - K(10) = 3 = D
• H(7) - E(4) = 3 = D
• R(17) - Y(24) = -7 + 26 = 19 = T
4. Convert Back to Letters: Convert the numbers back to letters: 1 19 7 5 10 23 20 1 19 3 3 19 = B T H F K X U B T D D T

In a transposition cipher, the order of the letters is rearranged. When rearranged, the original message becomes THE NUMBERS OMIT.

The ROT13 cipher shifts each letter by 13 positions in the alphabet.

y shifted 13 places becomes l

r shifted 13 places becomes e

g shifted 13 places becomes t

g shifted 13 places becomes t

r shifted 13 places becomes e

e shifted 13 places becomes r

f shifted 13 places becomes s

Thus, the decoded message is LETTERS.