Randomize stepping.

diff --git a/frontend/src/main.c b/frontend/src/main.c
index 6299c11..8980cca 100644 (file)
--- a/frontend/src/main.c
+++ b/frontend/src/main.c
@@ -60,7 +60,7 @@ static int weak_passphrase(const CHR *str)
 
 static int encrypt(const char* const passphrase, const CHR* const input, const CHR* const output)
 {
-       mcrypt_t ctx = NULL;
+       mcrypt_t ctx = MCRYPT_NULL;
        FILE *fin = NULL, *fout = NULL;
        int result = 1;
 
@@ -181,7 +181,7 @@ clean_up:
 
 static int decrypt(const char* const passphrase, const CHR* const input, const CHR* const output)
 {
-       mcrypt_t ctx = NULL;
+       mcrypt_t ctx = MCRYPT_NULL;
        FILE *fin = NULL, *fout = NULL;
        int result = 1;
 
@@ -312,7 +312,7 @@ static int self_test(void)
        
        const size_t length = strlen(text_plain) + 1U;
        int result = 1;
-       mcrypt_t ctx_enc = NULL, ctx_dec = NULL;
+       mcrypt_t ctx_enc = MCRYPT_NULL, ctx_dec = MCRYPT_NULL;
 
        FPUTS(T("Self-test is running, please be patient... "), stderr);
 

diff --git a/libMCrypt/include/mcrypt.h b/libMCrypt/include/mcrypt.h
index bc41307..317c8f9 100644 (file)
--- a/libMCrypt/include/mcrypt.h
+++ b/libMCrypt/include/mcrypt.h
@@ -15,7 +15,8 @@ extern const char* const LIBMCRYPT_BUILDNO;
 /*
  * Opaque handle to internal state
  */
-typedef void* mcrypt_t;
+typedef uintptr_t mcrypt_t;
+#define MCRYPT_NULL ((mcrypt_t)NULL)
 
 /*
  * Seed generator
@@ -23,9 +24,10 @@ typedef void* mcrypt_t;
 int mcrypt_generate_seed(uint64_t* const seed);
 
 /*
- * Allocate or free state
+ * Allocate, reset or free state
  */
 mcrypt_t mcrypt_alloc(const uint64_t salt, const char* const passphrase);
+int mcrypt_reset(const mcrypt_t context, const uint64_t salt, const char* const passphrase);
 void mcrypt_free(const mcrypt_t context);
 
 /*

diff --git a/libMCrypt/src/mcrypt.c b/libMCrypt/src/mcrypt.c
index 047ffb6..e09c033 100644 (file)
--- a/libMCrypt/src/mcrypt.c
+++ b/libMCrypt/src/mcrypt.c
@@ -15,10 +15,11 @@ const char* const LIBMCRYPT_BUILDNO = __DATE__", "__TIME__;
 
 typedef struct
 {
-       uint8_t box[256U][256U];
-       uint8_t inv[256U][256U];
-       uint8_t off[256U];
-       uint8_t pos;
+       uint8_t wheel_fwd[256U][256U];
+       uint8_t wheel_bwd[256U][256U];
+       uint8_t rot[256U];
+       uint8_t step[256U];
+       uint8_t counter;
 }
 crypt_state_t;
 
@@ -95,28 +96,37 @@ static void random_seed(rand_state_t* const state, const uint64_t salt, const ui
 
 static void initialize_state(crypt_state_t* const crypt_state, const uint64_t salt, const uint8_t* const key, const size_t key_len)
 {
+       crypt_state->counter = 0U;
        rand_state_t rand_state;
        for (size_t r = 0U; r < 256U; ++r)
        {
                random_seed(&rand_state, salt, (uint16_t)r, key, key_len);
-               crypt_state->off[r] = (uint8_t)random_next(&rand_state);
+               crypt_state->rot[r] = (uint8_t)random_next(&rand_state);
                for (size_t i = 0U; i < 256U; ++i)
                {
                        const size_t j = random_next(&rand_state) % (i + 1U);
                        if (j != i)
                        {
-                               crypt_state->box[r][i] = crypt_state->box[r][j];
+                               crypt_state->wheel_fwd[r][i] = crypt_state->wheel_fwd[r][j];
                        }
-                       crypt_state->box[r][j] = (uint8_t)i;
+                       crypt_state->wheel_fwd[r][j] = (uint8_t)i;
                }
                for (size_t i = 0U; i < 256U; ++i)
                {
-                       const size_t j = crypt_state->box[r][i];
-                       crypt_state->inv[r][j] = (uint8_t)i;
+                       const size_t j = crypt_state->wheel_fwd[r][i];
+                       crypt_state->wheel_bwd[r][j] = (uint8_t)i;
                }
        }
        random_seed(&rand_state, salt, 0x0100, key, key_len);
-       crypt_state->pos = (uint8_t)random_next(&rand_state);
+       for (size_t i = 0U; i < 256U; ++i)
+       {
+               const size_t j = random_next(&rand_state) % (i + 1U);
+               if (j != i)
+               {
+                       crypt_state->step[i] = crypt_state->step[j];
+               }
+               crypt_state->step[j] = (uint8_t)i;
+       }
        mcrypt_bzero(&rand_state, sizeof(rand_state_t));
 }
 
@@ -128,9 +138,9 @@ static uint8_t process_enc(crypt_state_t* const crypt_state, uint8_t value)
 {
        for (size_t i = 0U; i < 256U; ++i)
        {
-               value = crypt_state->box[i][(value + crypt_state->off[i]) & 0xFF];
+               value = crypt_state->wheel_fwd[i][(value + crypt_state->rot[i]) & 0xFF];
        }
-       ++crypt_state->off[crypt_state->pos++];
+       ++crypt_state->rot[crypt_state->step[crypt_state->counter++]];
        return value;
 }
 
@@ -139,9 +149,9 @@ static uint8_t process_dec(crypt_state_t* const crypt_state, uint8_t value)
        size_t i = 256U;
        while (i--)
        {
-               value = (crypt_state->inv[i][value] - crypt_state->off[i]) & 0xFF;
+               value = (crypt_state->wheel_bwd[i][value] - crypt_state->rot[i]) & 0xFF;
        }
-       ++crypt_state->off[crypt_state->pos++];
+       ++crypt_state->rot[crypt_state->step[crypt_state->counter++]];
        return value;
 }
 
@@ -173,10 +183,21 @@ mcrypt_t mcrypt_alloc(const uint64_t salt, const char* const passphrase)
        return ((mcrypt_t)state);
 }
 
+int mcrypt_reset(const mcrypt_t context, const uint64_t salt, const char* const passphrase)
+{
+       crypt_state_t* const state = (crypt_state_t*)context;
+       if ((!state) || (!passphrase))
+       {
+               return -1;
+       }
+       initialize_state(state, salt, (uint8_t*)passphrase, strlen(passphrase));
+       return 0;
+}
+
 int mcrypt_enc_process(const mcrypt_t context, const uint8_t* const input, uint8_t* const output, size_t length)
 {
        crypt_state_t* const state = (crypt_state_t*)context;
-       if (!context)
+       if (!state)
        {
                return -1;
        }
@@ -190,7 +211,7 @@ int mcrypt_enc_process(const mcrypt_t context, const uint8_t* const input, uint8
 int mcrypt_enc_process_inplace(const mcrypt_t context, uint8_t* const buffer, size_t length)
 {
        crypt_state_t* const state = (crypt_state_t*)context;
-       if (!context)
+       if (!state)
        {
                return -1;
        }
@@ -205,7 +226,7 @@ int mcrypt_enc_process_inplace(const mcrypt_t context, uint8_t* const buffer, si
 int mcrypt_dec_process(const mcrypt_t context, const uint8_t* const input, uint8_t* const output, size_t length)
 {
        crypt_state_t* const state = (crypt_state_t*)context;
-       if (!context)
+       if (!state)
        {
                return -1;
        }
@@ -219,7 +240,7 @@ int mcrypt_dec_process(const mcrypt_t context, const uint8_t* const input, uint8
 int mcrypt_dec_process_inplace(const mcrypt_t context, uint8_t* const buffer, size_t length)
 {
        crypt_state_t* const state = (crypt_state_t*)context;
-       if (!context)
+       if (!state)
        {
                return -1;
        }
@@ -233,9 +254,9 @@ int mcrypt_dec_process_inplace(const mcrypt_t context, uint8_t* const buffer, si
 void mcrypt_free(const mcrypt_t context)
 {
        crypt_state_t* const state = (crypt_state_t*)context;
-       if (context)
+       if (state)
        {
-               mcrypt_bzero((void*)context, sizeof(crypt_state_t));
-               free(context);
+               mcrypt_bzero(state, sizeof(crypt_state_t));
+               free(state);
        }
 }