signature_analysis.rb

ciphertexts = [
  "VGYURYPEDFNCEPGEWELLPVNWRDCNFGMGXQEPPRG-CBFIGLEMG",
  "EQ’PMEIGQNVBAGBTFEGMSYNRKMNWEPBLWBYPSNWMQNFBDWEQVYNR-CBFIGLEMG"
]

names = [
  "RYANNORTH",
  "BUBBLEGUM",
  "MARCELINE",
  "RAINICORN"
]

signature = "CBFIGLEMG"

known_keys   = signature.chars
all_keys     = ("A".."Z").to_a
unknown_keys = (all_keys - known_keys)

names.each do |name|
  puts "Name: #{name}"
  ciphertexts.each do |ciphertext|
    ciphertext_before = ciphertext
    ciphertext_after  = ciphertext.tr(signature, name)
    ciphertext_known_keys = ciphertext.tr(unknown_keys.join, "_").tr(signature, name)

    puts "Ciphertext before:     #{ciphertext_before}"
    puts "Ciphertext after:      #{ciphertext_after}"
    puts "Ciphertext known keys: #{ciphertext_known_keys}"
  end
end