Alice sends Bob the following ciphertexts:

LDPWKHORUGBRXUJRG
XNTRGZKKGZUDMNNSGDQFNCRADENQDLD
DTZXMFQQSTYRFPJDTZWXJQKFSDLWFAJSNRFLJ
SIOMBUFFHINNUEYNBYHUGYIZNBYFILXSIOLAIXCHPUCH
ERZRZOREGURFNOONGUQNLGBXRRCVGUBYL
CJIJPMTJPMAVOCZMVIYTJPMHJOCZM
DTZXMFQQSTYRZWIJW
ZPVTIBMMOPUDPNNJUBEVMUFSZ
FVBZOHSSUVAZALHS
KAGETMXXZAFSUHQRMXEQFQEFUYAZKMSMUZEFKAGDZQUSTNAGD
MCIGVOZZBCHRSGWFSOBMHVWBUHVOHPSZCBUGHCMCIFBSWUVPCIF

Charlie manages to capture the ciphertexts and he finds that the cipher used for encryption is the shift cipher (each message possibly encrypted with a different key). Can you decrypt the messages ?

Charlie also knows that the plaintext consists only of the English letters A to Z (all capitals, no punctuation).

Alice sends Bob another ciphertext, but much longer this time:

Download message file

Charlie needs to decrypt this as well. Some colleagues tell him this is encrypted using the substitution cipher, and that again the plaintext consists only of the English letters A to Z (all capitals, no punctuation). Try to help Charlie to decrypt this.

Hint: use the frequency analysis mechanisms we discussed in class. Note that the frequency of each letter does not map precisely. In particular, the most frequent two letters do match well with the given table, but the others are sometimes mixed. However, Charlie knows that the most frequent bi-grams are the following (from most frequent to less frequent): TH, HE, IN, OR, HA, ET, AN, EA, IS, OU, HI, ER, ST, RE, ND

With this information, can you tell what the ciphertext is about?