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-rw-r--r--modules/ciphers/rc6/rc6.cpp120
1 files changed, 120 insertions, 0 deletions
diff --git a/modules/ciphers/rc6/rc6.cpp b/modules/ciphers/rc6/rc6.cpp
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+++ b/modules/ciphers/rc6/rc6.cpp
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+/*************************************************
+* RC6 Source File *
+* (C) 1999-2007 Jack Lloyd *
+*************************************************/
+
+#include <botan/rc6.h>
+#include <botan/loadstor.h>
+#include <botan/bit_ops.h>
+#include <algorithm>
+
+namespace Botan {
+
+/*************************************************
+* RC6 Encryption *
+*************************************************/
+void RC6::enc(const byte in[], byte out[]) const
+ {
+ u32bit A = load_le<u32bit>(in, 0);
+ u32bit B = load_le<u32bit>(in, 1);
+ u32bit C = load_le<u32bit>(in, 2);
+ u32bit D = load_le<u32bit>(in, 3);
+
+ B += S[0]; D += S[1];
+
+ for(u32bit j = 0; j != 20; j += 4)
+ {
+ u32bit T1, T2;
+
+ T1 = rotate_left(B*(2*B+1), 5);
+ T2 = rotate_left(D*(2*D+1), 5);
+ A = rotate_left(A ^ T1, T2 % 32) + S[2*j+2];
+ C = rotate_left(C ^ T2, T1 % 32) + S[2*j+3];
+
+ T1 = rotate_left(C*(2*C+1), 5);
+ T2 = rotate_left(A*(2*A+1), 5);
+ B = rotate_left(B ^ T1, T2 % 32) + S[2*j+4];
+ D = rotate_left(D ^ T2, T1 % 32) + S[2*j+5];
+
+ T1 = rotate_left(D*(2*D+1), 5);
+ T2 = rotate_left(B*(2*B+1), 5);
+ C = rotate_left(C ^ T1, T2 % 32) + S[2*j+6];
+ A = rotate_left(A ^ T2, T1 % 32) + S[2*j+7];
+
+ T1 = rotate_left(A*(2*A+1), 5);
+ T2 = rotate_left(C*(2*C+1), 5);
+ D = rotate_left(D ^ T1, T2 % 32) + S[2*j+8];
+ B = rotate_left(B ^ T2, T1 % 32) + S[2*j+9];
+ }
+
+ A += S[42]; C += S[43];
+
+ store_le(out, A, B, C, D);
+ }
+
+/*************************************************
+* RC6 Decryption *
+*************************************************/
+void RC6::dec(const byte in[], byte out[]) const
+ {
+ u32bit A = load_le<u32bit>(in, 0);
+ u32bit B = load_le<u32bit>(in, 1);
+ u32bit C = load_le<u32bit>(in, 2);
+ u32bit D = load_le<u32bit>(in, 3);
+
+ C -= S[43]; A -= S[42];
+
+ for(u32bit j = 0; j != 20; j += 4)
+ {
+ u32bit T1, T2;
+
+ T1 = rotate_left(A*(2*A+1), 5);
+ T2 = rotate_left(C*(2*C+1), 5);
+ B = rotate_right(B - S[41 - 2*j], T1 % 32) ^ T2;
+ D = rotate_right(D - S[40 - 2*j], T2 % 32) ^ T1;
+
+ T1 = rotate_left(D*(2*D+1), 5);
+ T2 = rotate_left(B*(2*B+1), 5);
+ A = rotate_right(A - S[39 - 2*j], T1 % 32) ^ T2;
+ C = rotate_right(C - S[38 - 2*j], T2 % 32) ^ T1;
+
+ T1 = rotate_left(C*(2*C+1), 5);
+ T2 = rotate_left(A*(2*A+1), 5);
+ D = rotate_right(D - S[37 - 2*j], T1 % 32) ^ T2;
+ B = rotate_right(B - S[36 - 2*j], T2 % 32) ^ T1;
+
+ T1 = rotate_left(B*(2*B+1), 5);
+ T2 = rotate_left(D*(2*D+1), 5);
+ C = rotate_right(C - S[35 - 2*j], T1 % 32) ^ T2;
+ A = rotate_right(A - S[34 - 2*j], T2 % 32) ^ T1;
+ }
+
+ D -= S[1]; B -= S[0];
+
+ store_le(out, A, B, C, D);
+ }
+
+/*************************************************
+* RC6 Key Schedule *
+*************************************************/
+void RC6::key(const byte key[], u32bit length)
+ {
+ const u32bit WORD_KEYLENGTH = (((length - 1) / 4) + 1),
+ MIX_ROUNDS = 3*std::max(WORD_KEYLENGTH, S.size());
+ S[0] = 0xB7E15163;
+ for(u32bit j = 1; j != S.size(); ++j)
+ S[j] = S[j-1] + 0x9E3779B9;
+
+ SecureBuffer<u32bit, 8> K;
+ for(s32bit j = length-1; j >= 0; --j)
+ K[j/4] = (K[j/4] << 8) + key[j];
+ for(u32bit j = 0, A = 0, B = 0; j != MIX_ROUNDS; ++j)
+ {
+ A = rotate_left(S[j % S.size()] + A + B, 3);
+ B = rotate_left(K[j % WORD_KEYLENGTH] + A + B, (A + B) % 32);
+ S[j % S.size()] = A;
+ K[j % WORD_KEYLENGTH] = B;
+ }
+ }
+
+}