diff options
| -rw-r--r-- | src/idea.cpp | 38 |
1 files changed, 25 insertions, 13 deletions
diff --git a/src/idea.cpp b/src/idea.cpp index 267a14504..49c064073 100644 --- a/src/idea.cpp +++ b/src/idea.cpp @@ -13,17 +13,17 @@ namespace { /************************************************* * Multiplication modulo 65537 * *************************************************/ -inline void mul(u16bit& a, u16bit b) +inline u16bit mul(u16bit a, u16bit b) { if(a && b) { u32bit temp = static_cast<u32bit>(a) * b; a = static_cast<u16bit>(temp >> 16); b = static_cast<u16bit>(temp & 0xFFFF); - a = static_cast<u16bit>(b - a + ((b < a) ? 1 : 0)); + return static_cast<u16bit>(b - a + ((b < a) ? 1 : 0)); } else - a = static_cast<u16bit>(1 - a - b); + return static_cast<u16bit>(1 - a - b); } } @@ -40,24 +40,30 @@ void IDEA::enc(const byte in[], byte out[]) const for(u32bit j = 0; j != 8; ++j) { - mul(X1, EK[6*j+0]); + X1 = mul(X1, EK[6*j+0]); X2 += EK[6*j+1]; X3 += EK[6*j+2]; - mul(X4, EK[6*j+3]); + X4 = mul(X4, EK[6*j+3]); + u16bit T0 = X3; X3 ^= X1; - mul(X3, EK[6*j+4]); + X3 = mul(X3, EK[6*j+4]); + u16bit T1 = X2; X2 = static_cast<u16bit>((X2 ^ X4) + X3); - mul(X2, EK[6*j+5]); + X2 = mul(X2, EK[6*j+5]); X3 += X2; + X1 ^= X2; X4 ^= X3; X2 ^= T0; X3 ^= T1; } - mul(X1, EK[48]); X2 += EK[50]; X3 += EK[49]; mul(X4, EK[51]); + X1 = mul(X1, EK[48]); + X2 += EK[50]; + X3 += EK[49]; + X4 = mul(X4, EK[51]); store_be(out, X1, X3, X2, X4); } @@ -74,24 +80,30 @@ void IDEA::dec(const byte in[], byte out[]) const for(u32bit j = 0; j != 8; ++j) { - mul(X1, DK[6*j+0]); + X1 = mul(X1, DK[6*j+0]); X2 += DK[6*j+1]; X3 += DK[6*j+2]; - mul(X4, DK[6*j+3]); + X4 = mul(X4, DK[6*j+3]); + u16bit T0 = X3; X3 ^= X1; - mul(X3, DK[6*j+4]); + X3 = mul(X3, DK[6*j+4]); + u16bit T1 = X2; X2 = static_cast<u16bit>((X2 ^ X4) + X3); - mul(X2, DK[6*j+5]); + X2 = mul(X2, DK[6*j+5]); X3 += X2; + X1 ^= X2; X4 ^= X3; X2 ^= T0; X3 ^= T1; } - mul(X1, DK[48]); X2 += DK[50]; X3 += DK[49]; mul(X4, DK[51]); + X1 = mul(X1, DK[48]); + X2 += DK[50]; + X3 += DK[49]; + X4 = mul(X4, DK[51]); store_be(out, X1, X3, X2, X4); } |