8 #include <botan/xtea.h>
9 #include <botan/loadstor.h>
15 void xtea_encrypt_4(
const byte in[32],
byte out[32],
const u32bit EK[64])
18 load_be(in, L0, R0, L1, R1, L2, R2, L3, R3);
20 for(
size_t i = 0; i != 32; ++i)
22 L0 += (((R0 << 4) ^ (R0 >> 5)) +
R0) ^ EK[2*i];
23 L1 += (((R1 << 4) ^ (R1 >> 5)) +
R1) ^ EK[2*i];
24 L2 += (((R2 << 4) ^ (R2 >> 5)) +
R2) ^ EK[2*i];
25 L3 += (((R3 << 4) ^ (R3 >> 5)) +
R3) ^ EK[2*i];
27 R0 += (((L0 << 4) ^ (L0 >> 5)) + L0) ^ EK[2*i+1];
28 R1 += (((L1 << 4) ^ (L1 >> 5)) + L1) ^ EK[2*i+1];
29 R2 += (((L2 << 4) ^ (L2 >> 5)) + L2) ^ EK[2*i+1];
30 R3 += (((L3 << 4) ^ (L3 >> 5)) + L3) ^ EK[2*i+1];
33 store_be(out, L0, R0, L1, R1, L2, R2, L3, R3);
36 void xtea_decrypt_4(
const byte in[32],
byte out[32],
const u32bit EK[64])
39 load_be(in, L0, R0, L1, R1, L2, R2, L3, R3);
41 for(
size_t i = 0; i != 32; ++i)
43 R0 -= (((L0 << 4) ^ (L0 >> 5)) + L0) ^ EK[63 - 2*i];
44 R1 -= (((L1 << 4) ^ (L1 >> 5)) + L1) ^ EK[63 - 2*i];
45 R2 -= (((L2 << 4) ^ (L2 >> 5)) + L2) ^ EK[63 - 2*i];
46 R3 -= (((L3 << 4) ^ (L3 >> 5)) + L3) ^ EK[63 - 2*i];
48 L0 -= (((R0 << 4) ^ (R0 >> 5)) +
R0) ^ EK[62 - 2*i];
49 L1 -= (((R1 << 4) ^ (R1 >> 5)) +
R1) ^ EK[62 - 2*i];
50 L2 -= (((R2 << 4) ^ (R2 >> 5)) +
R2) ^ EK[62 - 2*i];
51 L3 -= (((R3 << 4) ^ (R3 >> 5)) +
R3) ^ EK[62 - 2*i];
54 store_be(out, L0, R0, L1, R1, L2, R2, L3, R3);
66 xtea_encrypt_4(in, out, &(this->EK[0]));
72 for(
size_t i = 0; i != blocks; ++i)
77 for(
size_t j = 0; j != 32; ++j)
79 L += (((R << 4) ^ (R >> 5)) + R) ^ EK[2*j];
80 R += (((L << 4) ^ (L >> 5)) + L) ^ EK[2*j+1];
97 xtea_decrypt_4(in, out, &(this->EK[0]));
103 for(
size_t i = 0; i != blocks; ++i)
108 for(
size_t j = 0; j != 32; ++j)
110 R -= (((L << 4) ^ (L >> 5)) + L) ^ EK[63 - 2*j];
111 L -= (((R << 4) ^ (R >> 5)) + R) ^ EK[62 - 2*j];
124 void XTEA::key_schedule(
const byte key[],
size_t)
127 for(
size_t i = 0; i != 4; ++i)
131 for(
size_t i = 0; i != 64; i += 2)
133 EK[i ] = D + UK[D % 4];
135 EK[i+1] = D + UK[(D >> 11) % 4];
void encrypt_n(const byte in[], byte out[], size_t blocks) const
T load_be(const byte in[], size_t off)
void decrypt_n(const byte in[], byte out[], size_t blocks) const
u32bit load_be< u32bit >(const byte in[], size_t off)
void store_be(u16bit in, byte out[2])