--- /dev/null
+#include "aes.hpp"
+
+/* static function prototypes */
+static byteArray word2bytes (word input);
+static word bytes2word (byte b0, byte b1, byte b2, byte b3);
+static void circular_left_shift (byteArray &bytes, int shift_amt);
+static void circular_right_shift (byteArray &bytes, int shift_amt);
+static byte mult (const byte ax, const byte bx);
+static byte xtimes (const byte bx);
+static void printState (byteArray &bytes, std::string name);
+
+AES::AES (const byteArray& key)
+ : Nb(4) // This is constant in AES
+ , Nk(key.size() / 4) // This can be either 4, 6, or 8 (128, 192, or 256 bit)
+ , Nr(Nk + Nb + 2)
+ , keySchedule(Nb * (Nr+1), 0x00000000)
+{
+ // Check the arguments
+ if (!(Nk == 4 || Nk == 6 || Nk == 8))
+ throw incorrectKeySizeException();
+
+ // Generate the Key Schedule
+ KeyExpansion (key, keySchedule);
+
+#if 0
+ std::printf ("Key Schedule\n");
+ for (int i=0; i<keySchedule.size()/4; ++i)
+ {
+ for (int j=0; j<4; ++j)
+ {
+ byteArray temp = word2bytes (keySchedule.at(i*4+j));
+ std::printf ("%.2x %.2x %.2x %.2x ", temp[0], temp[1], temp[2], temp[3]);
+ }
+ std::printf ("\n");
+ }
+#endif
+}
+
+byteArray AES::encrypt (const byteArray& plaintext) const
+{
+ // Make sure that the plaintext size is a multiple of 16
+ if (plaintext.size() != 16)
+ throw incorrectTextSizeException ();
+
+ int round;
+ byteArray state (plaintext);
+
+ /* Round 0 */
+ //std::printf ("Round 0\n");
+ //printState (state, "input");
+ AddRoundKey (state, GetRoundKey (0));
+
+ /* Round 1 to Nr-1 */
+ for (round=1; round<Nr; ++round)
+ {
+ //std::printf ("Round %d\n", round);
+ //printState (state, "start");
+ SubBytes (state);
+ //printState (state, "sbyte");
+ ShiftRows (state);
+ //printState (state, "srows");
+ MixColumns (state);
+ //printState (state, "mcols");
+ AddRoundKey (state, GetRoundKey (round));
+ }
+
+ /* Round Nr */
+ //std::printf ("Round %d\n", round);
+ //printState (state, "start");
+ SubBytes (state);
+ //printState (state, "sbyte");
+ ShiftRows (state);
+ //printState (state, "srows");
+ AddRoundKey (state, GetRoundKey (round));
+
+ return state;
+}
+
+byteArray AES::decrypt (const byteArray& ciphertext) const
+{
+ // Make sure that the plaintext size is a multiple of 16
+ if (ciphertext.size() != 16)
+ throw incorrectTextSizeException ();
+
+ int round = Nr;
+ byteArray state (ciphertext);
+
+ /* Round Nr-1 */
+ AddRoundKey (state, GetRoundKey (round));
+
+ /* Round Nr-2 to 1 */
+ for (round=Nr-1; round>0; --round)
+ {
+ InvShiftRows (state);
+ InvSubBytes (state);
+ AddRoundKey (state, GetRoundKey (round));
+ InvMixColumns (state);
+ }
+
+ /* Round 0 */
+ InvShiftRows (state);
+ InvSubBytes (state);
+ AddRoundKey (state, GetRoundKey (round));
+
+ return state;
+}
+
+void AES::KeyExpansion (const byteArray& key, wordArray& w) const
+{
+ const static word Rcon[] = {
+ 0x00000000,
+ 0x01000000,
+ 0x02000000,
+ 0x04000000,
+ 0x08000000,
+ 0x10000000,
+ 0x20000000,
+ 0x40000000,
+ 0x80000000,
+ 0x1b000000,
+ 0x36000000,
+ };
+
+
+ int i;
+ word temp;
+
+ /* Copy the key bits into the beginning of the word array */
+ for (i=0; i<Nk; ++i)
+ w[i] = bytes2word (key[i*4+0], key[i*4+1], key[i*4+2], key[i*4+3]);
+
+ for (i=Nk; i < (Nb * (Nr+1)); ++i)
+ {
+ temp = w[i-1]; // copy the previous word into temp
+
+ if (i % Nk == 0)
+ temp = SubWord (RotWord (temp)) ^ Rcon[i/Nk];
+ else if (Nk > 6 && i % Nk == 4)
+ temp = SubWord (temp);
+
+ w[i] = w[i-Nk] ^ temp;
+ }
+}
+
+void AES::SubBytes (byteArray &state) const
+{
+ int i;
+ static const byte sbox[] = {
+ /* 0 1 2 3 4 5 6 7 8 9 A B C D E F */
+ 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
+ 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
+ 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
+ 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
+ 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
+ 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
+ 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
+ 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
+ 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
+ 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
+ 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
+ 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
+ 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
+ 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
+ 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
+ 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16,
+ };
+
+ for (i=0; i<state.size(); ++i)
+ state[i] = sbox[state[i]];
+}
+
+void AES::InvSubBytes (byteArray& state) const
+{
+ if (state.size() != Nb * 4)
+ throw badStateArrayException ();
+
+ int i;
+ static const byte inv_sbox[] = {
+ /* 0 1 2 3 4 5 6 7 8 9 A B C D E F */
+ 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
+ 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
+ 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
+ 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
+ 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
+ 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
+ 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
+ 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
+ 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
+ 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
+ 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
+ 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
+ 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
+ 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
+ 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
+ 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d,
+ };
+
+ for (i=0; i<state.size(); ++i)
+ state[i] = inv_sbox[state[i]];
+}
+
+
+void AES::ShiftRows (byteArray& state) const
+{
+ if (state.size() != Nb * 4)
+ throw badStateArrayException ();
+
+ int r, c;
+ byteArray temp (Nb, 0);
+
+ for (r=0; r<state.size()/4; ++r)
+ {
+ // Copy into temp
+ for (c=0; c<Nb; ++c)
+ temp.at(c) = state.at ((c*state.size()/4)+r);
+
+#if 0
+ std::printf ("before cls(%d)=", r);
+ for (c=0; c<Nb; ++c)
+ std::printf ("%.2x", temp.at(c));
+ std::printf (" -- ");
+#endif
+
+ // CLS 0, 1, 2, 3
+ circular_left_shift (temp, r);
+
+#if 0
+ std::printf ("after cls(%d)=", r);
+ for (c=0; c<Nb; ++c)
+ std::printf ("%.2x", temp.at(c));
+ std::printf ("\n");
+#endif
+
+ // Copy back to state matrix
+ for (c=0; c<Nb; ++c)
+ state.at((c*state.size()/4)+r) = temp.at(c);
+ }
+}
+
+void AES::InvShiftRows (byteArray& state) const
+{
+ if (state.size() != Nb * 4)
+ throw badStateArrayException ();
+
+ int r, c;
+ byteArray temp (Nb, 0);
+
+ for (r=0; r<4; ++r)
+ {
+ // Copy into temp
+ for (c=0; c<temp.size(); ++c)
+ temp[c] = state[(c*4)+r];
+
+ // CRS 0, 1, 2, 3
+ circular_right_shift (temp, r);
+
+ // Copy back to state matrix
+ for (c=0; c<temp.size(); ++c)
+ state.at((c*4)+r) = temp.at(c);
+ }
+}
+
+void AES::MixColumns (byteArray& state) const
+{
+ if (state.size() != Nb * 4)
+ throw badStateArrayException ();
+
+ const static byte transform[] = {
+ 0x02, 0x03, 0x01, 0x01,
+ 0x01, 0x02, 0x03, 0x01,
+ 0x01, 0x01, 0x02, 0x03,
+ 0x03, 0x01, 0x01, 0x02,
+ };
+
+ int r, c, i, j;
+ byteArray temp (Nb, 0);
+ byteArray result (Nb, 0);
+ byte total;
+
+ for (r=0; r<4; ++r)
+ {
+ /* Get this column */
+ for (c=0; c<Nb; ++c)
+ temp[c] = state[(r*4)+c];
+
+ /* Do the Multiply */
+ for (i=0; i<4; ++i)
+ {
+ result[i] = 0x00;
+
+ for (j=0; j<4; ++j)
+ result[i] = result[i] ^ mult (transform[i*4+j], temp[j]);
+ }
+
+ /* Copy back into state matrix */
+ for (c=0; c<Nb; ++c)
+ state[(r*4)+c] = result[c];
+ }
+}
+
+void AES::InvMixColumns (byteArray& state) const
+{
+ if (state.size() != Nb * 4)
+ throw badStateArrayException ();
+
+ const static byte transform_inv[] = {
+ 0x0e, 0x0b, 0x0d, 0x09,
+ 0x09, 0x0e, 0x0b, 0x0d,
+ 0x0d, 0x09, 0x0e, 0x0b,
+ 0x0b, 0x0d, 0x09, 0x0e,
+ };
+
+ int r, c, i, j;
+ byteArray temp (Nb, 0);
+ byteArray result (Nb, 0);
+ byte total;
+
+ for (r=0; r<4; ++r)
+ {
+ /* Get this column */
+ for (c=0; c<Nb; ++c)
+ temp[c] = state[(r*4)+c];
+
+ /* Do the Multiply */
+ for (i=0; i<4; ++i)
+ {
+ result[i] = 0x00;
+
+ for (j=0; j<4; ++j)
+ result[i] ^= mult (transform_inv[(i*4)+j], temp[j]);
+ }
+
+ /* Copy back into state matrix */
+ for (c=0; c<Nb; ++c)
+ state[(r*4)+c] = result[c];
+ }
+}
+
+word AES::SubWord (const word& input) const
+{
+ byteArray bInput = word2bytes (input);
+
+ SubBytes (bInput);
+
+ return bytes2word (bInput[0], bInput[1], bInput[2], bInput[3]);
+}
+
+word AES::RotWord (const word& input) const
+{
+ byteArray bInput = word2bytes (input);
+
+ circular_left_shift (bInput, 1);
+
+ return bytes2word (bInput[0], bInput[1], bInput[2], bInput[3]);
+}
+
+wordArray AES::GetRoundKey (const int round) const
+{
+ wordArray temp (4, 0);
+
+ temp[0] = keySchedule.at (round*Nb + 0);
+ temp[1] = keySchedule.at (round*Nb + 1);
+ temp[2] = keySchedule.at (round*Nb + 2);
+ temp[3] = keySchedule.at (round*Nb + 3);
+
+#if 0
+ std::printf ("ksch%d ", round);
+ for (int i=0; i<4; ++i)
+ {
+ byteArray btemp = word2bytes (temp[i]);
+ std::printf ("%.2x%.2x%.2x%.2x", btemp[0], btemp[1], btemp[2], btemp[3]);
+ }
+ std::printf ("\n");
+#endif
+
+ return temp;
+}
+
+void AES::AddRoundKey (byteArray& state, const wordArray& w) const
+{
+ int i, j;
+
+ for (i=0; i<w.size(); ++i)
+ {
+ byteArray wBytes = word2bytes (w[i]);
+
+ for (j=0; j<Nb; ++j)
+ {
+ //std::printf ("state.at(%d) ^= wBytes.at(%d) -- %.2x ^ %.2x = %.2x\n", i*Nb+j, j, state.at (i*Nb+j), wBytes.at(j), state.at(i*Nb+j) ^ wBytes.at(j));
+ state.at(i*Nb+j) ^= wBytes.at(j);
+ }
+ }
+}
+
+/******************************************************************************
+ * STATIC FUNCTIONS *
+ ******************************************************************************/
+
+static word bytes2word (const byte b0, const byte b1, const byte b2, const byte b3)
+{
+ word output;
+ output = (0x00000000) | b0;
+ output = (output << 8) | b1;
+ output = (output << 8) | b2;
+ output = (output << 8) | b3;
+
+ return output;
+}
+
+static byteArray word2bytes (const word input)
+{
+ byteArray output (4, 0x00);
+ output[0] = (input & 0xff000000) >> 24;
+ output[1] = (input & 0x00ff0000) >> 16;
+ output[2] = (input & 0x0000ff00) >> 8;
+ output[3] = (input & 0x000000ff) >> 0;
+
+ return output;
+}
+
+static int ring_mod (const int number, const int mod_amt)
+{
+ int temp = number;
+
+ while (temp < 0)
+ temp += mod_amt;
+
+ return temp;
+}
+
+/* ROL all of the bytes in @bytes by @shift_amt */
+static void circular_left_shift (byteArray &bytes, int shift_amt)
+{
+ int i;
+ byteArray temp (bytes.size(), 0);
+
+#if 0
+ std::printf ("BEFORE CLS(%d): ", shift_amt);
+ for (i=0; i<bytes.size(); ++i)
+ std::printf ("%.2x", bytes[i]);
+ std::printf ("\n");
+#endif
+
+ for (i=0; i<temp.size(); ++i)
+ {
+ int tindex = i;
+ int bindex = (i+shift_amt) % bytes.size();
+ //std::printf ("temp[%d] = bytes[%d] = %.2x\n", tindex, bindex, bytes[bindex]);
+ temp[i] = bytes[(i+shift_amt) % bytes.size()];
+ }
+
+#if 0
+ std::printf ("AFTER CLS(%d): ", shift_amt);
+ for (i=0; i<temp.size(); ++i)
+ std::printf ("%.2x", temp[i]);
+ std::printf ("\n");
+#endif
+
+ for (i=0; i<bytes.size(); ++i)
+ bytes.at(i) = temp.at(i);
+}
+
+/* ROR all of the bytes in @bytes by @shift_amt */
+static void circular_right_shift (byteArray &bytes, int shift_amt)
+{
+ int i;
+ byteArray temp (bytes.size(), 0);
+
+ for (i=0; i<temp.size(); ++i)
+ temp[i] = bytes[ring_mod (i-shift_amt, bytes.size())];
+
+ for (i=0; i<bytes.size(); ++i)
+ bytes[i] = temp[i];
+}
+
+static byte xtimes (const byte bx)
+{
+ const byte mx = 0x1b; /* x^8 + x^4 + x^3 + x + 1 */
+
+ /* See Notes Pg 36. This is if b7 == 1 */
+ if (bx & 0x80)
+ return (bx << 1) ^ mx;
+
+ /* This is if b7 == 0 */
+ return (bx << 1);
+}
+
+static byte mult (const byte ax, const byte bx)
+{
+ int i;
+ byte xibx = bx;
+ byte ai;
+ byte total = 0x00;
+
+ for (i=0; i<8; ++i)
+ {
+ /* Find a0 through a7 */
+ ai = ax & (1 << i);
+
+ /* If ai is not zero, add it into the total */
+ if (ai)
+ total ^= xibx;
+
+ /* Update x^i * b(x) */
+ xibx = xtimes (xibx);
+ }
+
+ return total;
+}
+
+static void printState (byteArray &bytes, std::string name)
+{
+ int i;
+
+ std::cout << name << ": ";
+ for (i=0; i<16; ++i)
+ std::printf ("%.2x", bytes.at(i));
+
+ std::printf ("\n");
+}
+
+
+/* vim: set ts=4 sts=4 sw=4 noet tw=112 nowrap: */
projects / aes.git / commitdiff