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37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include <sys/param.h>
41 #include <sys/kernel.h>
42 #include <sys/module.h>
43 #include <sys/types.h>
44 #include <crypto/rc4/rc4.h>
47 swap_bytes(u_char *a, u_char *b)
57 * Initialize an RC4 state buffer using the supplied key,
58 * which can have arbitrary length.
61 rc4_init(struct rc4_state *const state, const u_char *key, int keylen)
66 /* Initialize state with identity permutation */
67 for (i = 0; i < 256; i++)
68 state->perm[i] = (u_char)i;
72 /* Randomize the permutation using key data */
73 for (j = i = k = 0; i < 256; i++) {
74 j += state->perm[i] + key[k];
75 swap_bytes(&state->perm[i], &state->perm[j]);
82 * Encrypt some data using the supplied RC4 state buffer.
83 * The input and output buffers may be the same buffer.
84 * Since RC4 is a stream cypher, this function is used
85 * for both encryption and decryption.
88 rc4_crypt(struct rc4_state *const state,
89 const u_char *inbuf, u_char *outbuf, int buflen)
94 for (i = 0; i < buflen; i++) {
96 /* Update modification indicies */
98 state->index2 += state->perm[state->index1];
100 /* Modify permutation */
101 swap_bytes(&state->perm[state->index1],
102 &state->perm[state->index2]);
104 /* Encrypt/decrypt next byte */
105 j = state->perm[state->index1] + state->perm[state->index2];
106 outbuf[i] = inbuf[i] ^ state->perm[j];
111 rc4_modevent(module_t mod, int type, void *unused)
122 static moduledata_t rc4_mod = {
127 DECLARE_MODULE(rc4, rc4_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
128 MODULE_VERSION(rc4, 1);