Breaking any code involves four basic steps:
1) Determining the language used
2) Determining the system used
3) Reconstructing the key
4) Reconstructing the plaintext
Consider this cipher:
Now apply the four steps:
1) Determining the language allows you to compare the cipher text to the suspected language. Our cryptanalysts usually start with English.
2) Determining the system: is this cipher using rearranged words, replaced words, or perhaps letter substitution? In this case, it's letter substitution.
3) Reconstructing the key: this step answers the question of how the code-maker changed the letters. In our example, every character shifted one letter to the right in the alphabet.
4) Reconstructing the plaintext: by applying the key from the previous step, you now have a solution:
1) Determining the language used
2) Determining the system used
3) Reconstructing the key
4) Reconstructing the plaintext
Consider this cipher:
Nffu nf bu uif qbsl bu oppo.
Now apply the four steps:
1) Determining the language allows you to compare the cipher text to the suspected language. Our cryptanalysts usually start with English.
2) Determining the system: is this cipher using rearranged words, replaced words, or perhaps letter substitution? In this case, it's letter substitution.
3) Reconstructing the key: this step answers the question of how the code-maker changed the letters. In our example, every character shifted one letter to the right in the alphabet.
4) Reconstructing the plaintext: by applying the key from the previous step, you now have a solution:
Meet me at the park at noon.
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