multByTwo - GF multiplication as specified in the EME-32 draft
| 62 | |
| 63 | // multByTwo - GF multiplication as specified in the EME-32 draft |
| 64 | static void multByTwo(BYTE *out, const BYTE *in, int len) { |
| 65 | if (len != 16) { |
| 66 | panic(L"len must be 16"); |
| 67 | } |
| 68 | BYTE tmp[16]; |
| 69 | |
| 70 | tmp[0] = 2 * in[0]; |
| 71 | if (in[15] >= 128) { |
| 72 | tmp[0] = tmp[0] ^ 135; |
| 73 | } |
| 74 | for (int j = 1; j < 16; j++) { |
| 75 | tmp[j] = 2 * in[j]; |
| 76 | if (in[j - 1] >= 128) { |
| 77 | tmp[j] += 1; |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | for (int i = 0; i < 16; i++) |
| 82 | out[i] = tmp[i]; |
| 83 | } |
| 84 | |
| 85 | static void xorBlocks(BYTE* out, const BYTE* in1, const BYTE* in2, int len) { |
| 86 |
no test coverage detected