diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/examples/xor_ciph.cpp | 34 |
1 files changed, 16 insertions, 18 deletions
diff --git a/doc/examples/xor_ciph.cpp b/doc/examples/xor_ciph.cpp index b57fbfc4d..92902a483 100644 --- a/doc/examples/xor_ciph.cpp +++ b/doc/examples/xor_ciph.cpp @@ -15,35 +15,31 @@ class XOR_Cipher : public StreamCipher public: // what we want to call this cipher std::string name() const { return "XOR"; } + // return a new object of this type StreamCipher* clone() const { return new XOR_Cipher; } - // StreamCipher() can take a number of args, which are: - // min keylen, max keylen, keylength mod, iv size - // In this case we just pass min keylen, which means the - // only keysize we support is 1 byte, and don't use an IV. - XOR_Cipher() : StreamCipher(1) { mask = 0; } + + XOR_Cipher() : StreamCipher(1, 32) { mask_pos = 0; } private: void cipher(const byte[], byte[], u32bit); void key(const byte[], u32bit); - byte mask; + + SecureVector<byte> mask; + u32bit mask_pos; }; void XOR_Cipher::cipher(const byte in[], byte out[], u32bit length) { for(u32bit j = 0; j != length; j++) - out[j] = in[j] ^ mask; + { + out[j] = in[j] ^ mask[mask_pos]; + mask_pos = (mask_pos + 1) % mask.size(); + } } -void XOR_Cipher::key(const byte key[], u32bit) +void XOR_Cipher::key(const byte key[], u32bit length) { - /* We know length == 1 because it is checked in set_key against the - constraints we passed to StreamCipher's constructor. In this case, - we said: "All keys are of length 1 byte and no other length". - - An excercise for the reader would be to extend this to support - arbitrary length (for arbitrary in the range 1-32) keys. - */ - mask = key[0]; + mask.set(key, length); } #include <fstream> @@ -55,15 +51,17 @@ void XOR_Cipher::key(const byte key[], u32bit) #include <botan/look_add.h> #include <botan/lookup.h> #include <botan/filters.h> +#include <botan/config.h> int main() { LibraryInitializer init; add_algorithm(new XOR_Cipher); // make it available to use - add_alias("Vernam", "XOR"); // make Vernam an alias for XOR + global_config().add_alias("Vernam", "XOR"); // make Vernam an alias for XOR - SymmetricKey key("42"); // a key of length 1, value hex 42 == dec 66 + // a hex key value + SymmetricKey key("010203040506070809101112AAFF"); /* Since stream ciphers are typically additive, the encryption and |