/** diagnostic trace of static tables. */
public static void trace_static() {
int i, j;
System.out.print("AES Static Tablesn");
System.out.print("S[] = n");
for (i = 0; i < 16; i++) {
for (j = 0; j < 16; j++) System.out.print(Util.toHEX1(S[i * 16 + j]) + ", ");
System.out.println();
}
System.out.print("Si[] = n");
for (i = 0; i < 16; i++) {
for (j = 0; j < 16; j++) System.out.print(Util.toHEX1(Si[i * 16 + j]) + ", ");
System.out.println();
}
System.out.print("rcon[] = n");
for (i = 0; i < 5; i++) {
for (j = 0; j < 6; j++) System.out.print(Util.toHEX1(rcon[i * 6 + j]) + ", ");
System.out.println();
}
System.out.print("log[] = n");
for (i = 0; i < 32; i++) {
for (j = 0; j < 8; j++) System.out.print(Util.toHEX1(log[i * 8 + j]) + ", ");
System.out.println();
}
System.out.print("alog[] = n");
for (i = 0; i < 32; i++) {
for (j = 0; j < 8; j++) System.out.print(Util.toHEX1(alog[i * 8 + j]) + ", ");
System.out.println();
}
}
/**
* Expand a user-supplied key material into a session key.
*
* <p>See FIPS-197 Section 5.3 Fig 11 for details of the key expansion.
*
* <p>Session keys will be saved in Ke and Kd instance variables, along with numRounds being the
* number of rounds for this sized key.
*
* @param key The 128/192/256-bit AES key to use.
*/
@SuppressWarnings("unused")
public void setKey(byte[] key) {
// assorted internal constants
final int BC = BLOCK_SIZE / 4;
final int Klen = key.length;
final int Nk = Klen / 4;
int i, j, r;
traceInfo = ""; // reset trace info
if (traceLevel > 0) traceInfo = "setKey(" + Util.toHEX1(key) + ")n";
// check for bad arguments
if (key == null) throw new IllegalArgumentException("Empty key");
if (!(key.length == 16 || key.length == 24 || key.length == 32))
throw new IllegalArgumentException("Incorrect key length");
// set master number of rounds given size of this key
numRounds = getRounds(Klen);
final int ROUND_KEY_COUNT = (numRounds + 1) * BC;
// allocate 4 arrays of bytes to hold the session key values
// each array holds 1 of the 4 bytes [b0 b1 b2 b3] in each word w
byte[] w0 = new byte[ROUND_KEY_COUNT];
byte[] w1 = new byte[ROUND_KEY_COUNT];
byte[] w2 = new byte[ROUND_KEY_COUNT];
byte[] w3 = new byte[ROUND_KEY_COUNT];
// allocate arrays to hold en/decrypt session keys (by byte rather than word)
Ke = new byte[numRounds + 1][BLOCK_SIZE]; // encryption round keys
Kd = new byte[numRounds + 1][BLOCK_SIZE]; // decryption round keys
// copy key into start of session array (by word, each byte in own array)
for (i = 0, j = 0; i < Nk; i++) {
w0[i] = key[j++];
w1[i] = key[j++];
w2[i] = key[j++];
w3[i] = key[j++];
}
// implement key expansion algorithm
byte t0, t1, t2, t3, old0; // temp byte values for each word
for (i = Nk; i < ROUND_KEY_COUNT; i++) {
t0 = w0[i - 1];
t1 = w1[i - 1];
t2 = w2[i - 1];
t3 = w3[i - 1]; // temp = w[i-1]
if (i % Nk == 0) {
// temp = SubWord(RotWord(temp)) ^ Rcon[i/Nk]
old0 = t0; // save old 1st byte value for t3 calc
t0 = (byte) (S[t1 & 0xFF] ^ rcon[i / Nk]); // nb. constant XOR 1st byte only
t1 = (byte) (S[t2 & 0xFF]);
t2 = (byte) (S[t3 & 0xFF]); // nb. RotWord done by reordering bytes used
t3 = (byte) (S[old0 & 0xFF]);
} else if ((Nk > 6) && (i % Nk == 4)) {
// temp = SubWord(temp)
t0 = S[t0 & 0xFF];
t1 = S[t1 & 0xFF];
t2 = S[t2 & 0xFF];
t3 = S[t3 & 0xFF];
}
// w[i] = w[i-Nk] ^ temp
w0[i] = (byte) (w0[i - Nk] ^ t0);
w1[i] = (byte) (w1[i - Nk] ^ t1);
w2[i] = (byte) (w2[i - Nk] ^ t2);
w3[i] = (byte) (w3[i - Nk] ^ t3);
}
// now copy values into en/decrypt session arrays by round & byte in round
for (r = 0, i = 0; r < numRounds + 1; r++) { // for each round
for (j = 0; j < BC; j++) { // for each word in round
Ke[r][4 * j] = w0[i];
Ke[r][4 * j + 1] = w1[i];
Ke[r][4 * j + 2] = w2[i];
Ke[r][4 * j + 3] = w3[i];
Kd[numRounds - r][4 * j] = w0[i];
Kd[numRounds - r][4 * j + 1] = w1[i];
Kd[numRounds - r][4 * j + 2] = w2[i];
Kd[numRounds - r][4 * j + 3] = w3[i];
i++;
}
}
// create trace info if needed
if (traceLevel > 3) {
traceInfo += " Encrypt Round keys:n";
for (r = 0; r < numRounds + 1; r++)
traceInfo += " R" + r + "t = " + Util.toHEX1(Ke[r]) + "n";
traceInfo += " Decrypt Round keys:n";
for (r = 0; r < numRounds + 1; r++)
traceInfo += " R" + r + "t = " + Util.toHEX1(Kd[r]) + "n";
}
}
/**
* AES decrypt 128-bit ciphertext using key previously set.
*
* <p>Follows cipher specification given in FIPS-197 section 5.3 See pseudo code in Fig 5, and
* details in this section.
*
* @param cipher the 128-bit ciphertext value to decrypt.
* @return the decrypted 128-bit plaintext value.
*/
public byte[] decrypt(byte[] cipher) {
// define working variables
byte[] a = new byte[BLOCK_SIZE]; // AES state variable
byte[] ta = new byte[BLOCK_SIZE]; // AES temp state variable
byte[] Kdr; // encrypt keys for current round
int i, k, row, col;
traceInfo = ""; // reset trace info
if (traceLevel > 0) traceInfo = "decryptAES(" + Util.toHEX1(cipher) + ")";
// check for bad arguments
if (cipher == null) throw new IllegalArgumentException("Empty ciphertext");
if (cipher.length != BLOCK_SIZE)
throw new IllegalArgumentException("Incorrect ciphertext length");
// copy ciphertext bytes into state and do initial AddRoundKey(state)
Kdr = Kd[0];
for (i = 0; i < BLOCK_SIZE; i++) a[i] = (byte) (cipher[i] ^ Kdr[i]);
if (traceLevel > 2)
traceInfo += "n R0 (Key = " + Util.toHEX1(Kdr) + ")nt AK = " + Util.toHEX1(a);
else if (traceLevel > 1)
traceInfo += "n R0 (Key = " + Util.toHEX1(Kdr) + ")t = " + Util.toHEX1(a);
// for each round except last, apply round transforms
for (int r = 1; r < numRounds; r++) {
Kdr = Kd[r]; // get session keys for this round
if (traceLevel > 1) traceInfo += "n R" + r + " (Key = " + Util.toHEX1(Kdr) + ")t";
// InvShiftRows(state) into ta (nb. same shift as encrypt but subtract)
for (i = 0; i < BLOCK_SIZE; i++) {
row = i % COL_SIZE;
// get shifted byte index
k = (i + BLOCK_SIZE - (row_shift[row] * COL_SIZE)) % BLOCK_SIZE;
ta[i] = a[k];
}
if (traceLevel > 2) traceInfo += "ntISR = " + Util.toHEX1(ta);
// InvSubBytes(state) into a using inverse S-box Si
for (i = 0; i < BLOCK_SIZE; i++) a[i] = Si[ta[i] & 0xFF];
if (traceLevel > 2) traceInfo += "ntISB = " + Util.toHEX1(a);
// AddRoundKey(state) into ta
for (i = 0; i < BLOCK_SIZE; i++) ta[i] = (byte) (a[i] ^ Kdr[i]);
if (traceLevel > 2) traceInfo += "nt AK = " + Util.toHEX1(ta);
// InvMixColumns(state) into a
// implemented by expanding matrix mult for each column
// see FIPS-197 section 5.3.3
for (col = 0; col < NUM_COLS; col++) {
i = col * COL_SIZE; // start index for this col
a[i] =
(byte)
(mul(0x0e, ta[i])
^ mul(0x0b, ta[i + 1])
^ mul(0x0d, ta[i + 2])
^ mul(0x09, ta[i + 3]));
a[i + 1] =
(byte)
(mul(0x09, ta[i])
^ mul(0x0e, ta[i + 1])
^ mul(0x0b, ta[i + 2])
^ mul(0x0d, ta[i + 3]));
a[i + 2] =
(byte)
(mul(0x0d, ta[i])
^ mul(0x09, ta[i + 1])
^ mul(0x0e, ta[i + 2])
^ mul(0x0b, ta[i + 3]));
a[i + 3] =
(byte)
(mul(0x0b, ta[i])
^ mul(0x0d, ta[i + 1])
^ mul(0x09, ta[i + 2])
^ mul(0x0e, ta[i + 3]));
}
if (traceLevel > 2) traceInfo += "ntIMC";
if (traceLevel > 1) traceInfo += " = " + Util.toHEX1(a);
}
// last round is special - only has InvShiftRows, InvSubBytes and AddRoundKey
Kdr = Kd[numRounds]; // get session keys for final round
if (traceLevel > 1) traceInfo += "n R" + numRounds + " (Key = " + Util.toHEX1(Kdr) + ")t";
// InvShiftRows(state) into ta
for (i = 0; i < BLOCK_SIZE; i++) {
row = i % COL_SIZE;
// get shifted byte index
k = (i + BLOCK_SIZE - (row_shift[row] * COL_SIZE)) % BLOCK_SIZE;
ta[i] = a[k];
}
if (traceLevel > 2) traceInfo += "ntISR = " + Util.toHEX1(a);
// InvSubBytes(state) into ta using inverse S-box Si
for (i = 0; i < BLOCK_SIZE; i++) ta[i] = Si[ta[i] & 0xFF];
if (traceLevel > 2) traceInfo += "ntISB = " + Util.toHEX1(a);
// AddRoundKey(state) into a
for (i = 0; i < BLOCK_SIZE; i++) a[i] = (byte) (ta[i] ^ Kdr[i]);
if (traceLevel > 2) traceInfo += "nt AK";
if (traceLevel > 1) traceInfo += " = " + Util.toHEX1(a) + "n";
if (traceLevel > 0) traceInfo += " = " + Util.toHEX1(a) + "n";
return (a);
}
/**
* AES encrypt 128-bit plaintext using key previously set.
*
* <p>Follows cipher specification given in FIPS-197 section 5.1 See pseudo code in Fig 5, and
* details in this section.
*
* @param plain the 128-bit plaintext value to encrypt.
* @return the encrypted 128-bit ciphertext value.
*/
public byte[] encrypt(byte[] plain) {
// define working variables
byte[] a = new byte[BLOCK_SIZE]; // AES state variable
byte[] ta = new byte[BLOCK_SIZE]; // AES temp state variable
byte[] Ker; // encrypt keys for current round
int i, k, row, col;
traceInfo = ""; // reset trace info
if (traceLevel > 0) traceInfo = "encryptAES(" + Util.toHEX1(plain) + ")";
// check for bad arguments
if (plain == null) throw new IllegalArgumentException("Empty plaintext");
if (plain.length != BLOCK_SIZE)
throw new IllegalArgumentException("Incorrect plaintext length");
// copy plaintext bytes into state and do initial AddRoundKey(state)
Ker = Ke[0];
for (i = 0; i < BLOCK_SIZE; i++) a[i] = (byte) (plain[i] ^ Ker[i]);
if (traceLevel > 2)
traceInfo += "n R0 (Key = " + Util.toHEX1(Ker) + ")ntAK = " + Util.toHEX1(a);
else if (traceLevel > 1)
traceInfo += "n R0 (Key = " + Util.toHEX1(Ker) + ")t = " + Util.toHEX1(a);
// for each round except last, apply round transforms
for (int r = 1; r < numRounds; r++) {
Ker = Ke[r]; // get session keys for this round
if (traceLevel > 1) traceInfo += "n R" + r + " (Key = " + Util.toHEX1(Ker) + ")t";
// SubBytes(state) into ta using S-Box S
for (i = 0; i < BLOCK_SIZE; i++) ta[i] = S[a[i] & 0xFF];
if (traceLevel > 2) traceInfo += "ntSB = " + Util.toHEX1(ta);
// ShiftRows(state) into a
for (i = 0; i < BLOCK_SIZE; i++) {
row = i % COL_SIZE;
k = (i + (row_shift[row] * COL_SIZE)) % BLOCK_SIZE; // get shifted byte index
a[i] = ta[k];
}
if (traceLevel > 2) traceInfo += "ntSR = " + Util.toHEX1(a);
// MixColumns(state) into ta
// implemented by expanding matrix mult for each column
// see FIPS-197 section 5.1.3
for (col = 0; col < NUM_COLS; col++) {
i = col * COL_SIZE; // start index for this col
ta[i] = (byte) (mul(2, a[i]) ^ mul(3, a[i + 1]) ^ a[i + 2] ^ a[i + 3]);
ta[i + 1] = (byte) (a[i] ^ mul(2, a[i + 1]) ^ mul(3, a[i + 2]) ^ a[i + 3]);
ta[i + 2] = (byte) (a[i] ^ a[i + 1] ^ mul(2, a[i + 2]) ^ mul(3, a[i + 3]));
ta[i + 3] = (byte) (mul(3, a[i]) ^ a[i + 1] ^ a[i + 2] ^ mul(2, a[i + 3]));
}
if (traceLevel > 2) traceInfo += "ntMC = " + Util.toHEX1(ta);
// AddRoundKey(state) into a
for (i = 0; i < BLOCK_SIZE; i++) a[i] = (byte) (ta[i] ^ Ker[i]);
if (traceLevel > 2) traceInfo += "ntAK";
if (traceLevel > 1) traceInfo += " = " + Util.toHEX1(a);
}
// last round is special - only has SubBytes, ShiftRows and AddRoundKey
Ker = Ke[numRounds]; // get session keys for final round
if (traceLevel > 1) traceInfo += "n R" + numRounds + " (Key = " + Util.toHEX1(Ker) + ")t";
// SubBytes(state) into a using S-Box S
for (i = 0; i < BLOCK_SIZE; i++) a[i] = S[a[i] & 0xFF];
if (traceLevel > 2) traceInfo += "ntSB = " + Util.toHEX1(a);
// ShiftRows(state) into ta
for (i = 0; i < BLOCK_SIZE; i++) {
row = i % COL_SIZE;
k = (i + (row_shift[row] * COL_SIZE)) % BLOCK_SIZE; // get shifted byte index
ta[i] = a[k];
}
if (traceLevel > 2) traceInfo += "ntSR = " + Util.toHEX1(a);
// AddRoundKey(state) into a
for (i = 0; i < BLOCK_SIZE; i++) a[i] = (byte) (ta[i] ^ Ker[i]);
if (traceLevel > 2) traceInfo += "ntAK";
if (traceLevel > 1) traceInfo += " = " + Util.toHEX1(a) + "n";
if (traceLevel > 0) traceInfo += " = " + Util.toHEX1(a) + "n";
return (a);
}