50  * @brief read keys from keybuf into keys
51  * @param keybuf buffer containing the keys
52  * @param keys output key array containing the keys for encryption in
55 static void multiswap_init(const uint8_t keybuf[48], uint32_t keys[12])  in multiswap_init()
59         keys[i] = AV_RL32(keybuf + (i << 2)) | 1;  in multiswap_init()
63  * @brief invert the keys so that encryption become decryption keys and
65  * @param keys key array of ints to invert
67 static void multiswap_invert_keys(uint32_t keys[12])  in multiswap_invert_keys()
71         keys[i] = inverse(keys[i]);  in multiswap_invert_keys()
73         keys[i] = inverse(keys[i]);  in multiswap_invert_keys()
76 static uint32_t multiswap_step(const uint32_t keys[12], uint32_t v)  in multiswap_step()
79     v *= keys[0];  in multiswap_step()
82         v *= keys[i];  in multiswap_step()
84     v += keys[5];  in multiswap_step()
88 static uint32_t multiswap_inv_step(const uint32_t keys[12], uint32_t v)  in multiswap_inv_step()
91     v -= keys[5];  in multiswap_inv_step()
93         v *= keys[i];  in multiswap_inv_step()
96     v *= keys[0];  in multiswap_inv_step()
102  * @param keys 32 bit numbers in machine endianness,
108 static uint64_t multiswap_enc(const uint32_t keys[12],  in multiswap_enc()
116     tmp = multiswap_step(keys, a);  in multiswap_enc()
119     tmp = multiswap_step(keys + 6, b);  in multiswap_enc()
126  * @param keys 32 bit numbers in machine endianness,
132 static uint64_t multiswap_dec(const uint32_t keys[12],  in multiswap_dec()
140     b   = multiswap_inv_step(keys + 6, tmp);  in multiswap_dec()
143     a   = multiswap_inv_step(keys, tmp);  in multiswap_dec()