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authorlloyd <[email protected]>2008-09-28 19:29:24 +0000
committerlloyd <[email protected]>2008-09-28 19:29:24 +0000
commit9bcfe627321ddc81691b835dffaa6324ac4684a4 (patch)
treefe5e8ae9813b853549558b59833022e87e83981b /src/cipher/arc4/arc4.cpp
parent9822a701516396b7de4e41339faecd48ff8dc8ff (diff)
Move all modules into src/ directory
Diffstat (limited to 'src/cipher/arc4/arc4.cpp')
-rw-r--r--src/cipher/arc4/arc4.cpp103
1 files changed, 103 insertions, 0 deletions
diff --git a/src/cipher/arc4/arc4.cpp b/src/cipher/arc4/arc4.cpp
new file mode 100644
index 000000000..238567cdc
--- /dev/null
+++ b/src/cipher/arc4/arc4.cpp
@@ -0,0 +1,103 @@
+/*************************************************
+* ARC4 Source File *
+* (C) 1999-2007 Jack Lloyd *
+*************************************************/
+
+#include <botan/arc4.h>
+#include <botan/xor_buf.h>
+#include <botan/parsing.h>
+
+namespace Botan {
+
+/*************************************************
+* Combine cipher stream with message *
+*************************************************/
+void ARC4::cipher(const byte in[], byte out[], u32bit length)
+ {
+ while(length >= buffer.size() - position)
+ {
+ xor_buf(out, in, buffer.begin() + position, buffer.size() - position);
+ length -= (buffer.size() - position);
+ in += (buffer.size() - position);
+ out += (buffer.size() - position);
+ generate();
+ }
+ xor_buf(out, in, buffer.begin() + position, length);
+ position += length;
+ }
+
+/*************************************************
+* Generate cipher stream *
+*************************************************/
+void ARC4::generate()
+ {
+ u32bit SX, SY;
+ for(u32bit j = 0; j != buffer.size(); j += 4)
+ {
+ SX = state[X+1]; Y = (Y + SX) % 256; SY = state[Y];
+ state[X+1] = SY; state[Y] = SX;
+ buffer[j] = state[(SX + SY) % 256];
+
+ SX = state[X+2]; Y = (Y + SX) % 256; SY = state[Y];
+ state[X+2] = SY; state[Y] = SX;
+ buffer[j+1] = state[(SX + SY) % 256];
+
+ SX = state[X+3]; Y = (Y + SX) % 256; SY = state[Y];
+ state[X+3] = SY; state[Y] = SX;
+ buffer[j+2] = state[(SX + SY) % 256];
+
+ X = (X + 4) % 256;
+ SX = state[X]; Y = (Y + SX) % 256; SY = state[Y];
+ state[X] = SY; state[Y] = SX;
+ buffer[j+3] = state[(SX + SY) % 256];
+ }
+ position = 0;
+ }
+
+/*************************************************
+* ARC4 Key Schedule *
+*************************************************/
+void ARC4::key(const byte key[], u32bit length)
+ {
+ clear();
+ for(u32bit j = 0; j != 256; ++j)
+ state[j] = j;
+ for(u32bit j = 0, state_index = 0; j != 256; ++j)
+ {
+ state_index = (state_index + key[j % length] + state[j]) % 256;
+ std::swap(state[j], state[state_index]);
+ }
+ for(u32bit j = 0; j <= SKIP; j += buffer.size())
+ generate();
+ position += (SKIP % buffer.size());
+ }
+
+/*************************************************
+* Return the name of this type *
+*************************************************/
+std::string ARC4::name() const
+ {
+ if(SKIP == 0) return "ARC4";
+ if(SKIP == 256) return "MARK-4";
+ else return "RC4_skip(" + to_string(SKIP) + ")";
+ }
+
+/*************************************************
+* Clear memory of sensitive data *
+*************************************************/
+void ARC4::clear() throw()
+ {
+ state.clear();
+ buffer.clear();
+ position = X = Y = 0;
+ }
+
+/*************************************************
+* ARC4 Constructor *
+*************************************************/
+ARC4::ARC4(u32bit s) : StreamCipher(1, 256), SKIP(s)
+ {
+ clear();
+ }
+
+}