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| − | Cryptography is the process of hiding messages; either by concealing them (eg. hiding them in an image), or by obfuscating them outright (eg. substitution cipher).
| + | To learn about cryptography, check out the [http://gamedetectives.net/academy Game Detectives Academy] - a free, interactive series of tutorials! |
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| − | == Basic Terminology ==
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| − | * '''Cipher''': a method of encryption
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| − | * '''Plaintext''': the legible text of a hidden message
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| − | * '''Ciphertext''': the text after a message is concealed in it
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| − | * '''Encryption''': The process of turning plaintext into ciphertext
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| − | * '''Decryption''': The process of converting ciphertext back into plaintext
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| − | * '''Key''': a string used in the encryption and decryption processes of some ciphers, akin to a password
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| − | == Basic Ciphers ==
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| − | === Caesar cipher ===
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| − | ''Click [http://www.xarg.org/tools/caesar-cipher/ here] to experiment with the Caesar cipher.''
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| − | The simplest example of a cipher is the Caesar cipher. The rules of the cipher are as follows:
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| − | Let '''n''' equal a value from 1 to 25
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| − | Shift each letter in the plaintext forward by '''n''' positions in the alphabet
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| − | The resultant string is the ciphertext
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| − | For example, to encrypt the string <code>Game Detectives</code> using the Caesar cipher, using an arbitrary '''n''' value of 2, then:
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| − | G -> H -> I
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| − | a -> b -> c
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| − | m -> n -> o
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| − | e -> f -> g
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| − | ...
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| − | and the resultant ciphertext would be <code>Icog Fgvgevkxgu</code>. To decrypt this string back into <code>Game Detectives</code>, the process can simply be reversed by shifting each letter of the ciphertext 2 places backwards. (''Note: another common name for the Caesar cipher is ROT<n> - ROT13 indicates that each letter is shifted halfway through the alphabet)''
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| − | === Hex cipher ===
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| − | The Hex cipher, and other variants (such as Octal, Decimal, and Base64), rely on the fact that each ASCII character that you can type has a unique identifying number. For example,
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