diff options
| -rw-r--r-- | lib/aes.go | 34 |
1 files changed, 34 insertions, 0 deletions
@@ -3,6 +3,40 @@ package lib +func AESInvCipher(in, ky []byte) []byte { + nb := 4 + nr := 10 + + // Generate key schedule from key. + ks := KeyExpansion(ky) + + // Make state from input and do first round key + // transformation. + state := MkState(in) + state = AddRoundKey(state, ks[(nr*nb):((nr+1)*nb)]) + + for round := nr - 1; round >= 1; round-- { + state = InvShiftRows(state) + state = InvSubBytes(state) + state = AddRoundKey(state, ks[(round*nb):((round+1)*nb)]) + state = InvMixColumns(state) + } + state = InvShiftRows(state) + state = InvSubBytes(state) + state = AddRoundKey(state, ks[0:nb]) + + // Make output. + output := make([]byte, 4*nb) + i := 0 + for c := 0; c < nb; c++ { + for r := 0; r < 4; r++ { + output[i] = state[r][c] + i++ + } + } + return output +} + func InvMixColumns(state [][]byte) [][]byte { // Initialize new state. |