Changeset d7dadcb4 in mainline for uspace/lib/crypto/aes.c

Timestamp:

2015-04-08T10:54:31Z (10 years ago)

Author:

Jan Kolarik <kolarik@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

053fc2b

Parents:

1dcc0b9

Message:

RC4 and MD5 algorithm used in TKIP/WEP security suites

File:

• uspace/lib/crypto/aes.c (modified) (17 diffs)

uspace/lib/crypto/aes.c

@@ -29 +29 @@
 /** @file aes.c
  * 
- * Implementation of AES algorithm.
+ * Implementation of AES-128 symmetric cipher cryptographic algorithm.
  * 
  * Based on FIPS 197.
  */
 
-#include <stdio.h>
+#include <stdbool.h>
 #include <errno.h>
 #include <mem.h>
@@ -60 +60 @@
 
 /* Precomputed values for AES sub_byte transformation. */
-static const uint8_t sub_byte_array[BLOCK_LEN][BLOCK_LEN] = {
+static const uint8_t sbox[BLOCK_LEN][BLOCK_LEN] = {
         {
                 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 
@@ -128 +128 @@
 
 /* Precomputed values for AES inv_sub_byte transformation. */
-static uint8_t inv_sub_byte_array[BLOCK_LEN][BLOCK_LEN] = {
+static uint8_t inv_sbox[BLOCK_LEN][BLOCK_LEN] = {
         {
                 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 
@@ -202 +202 @@
 };
 
+/**
+ * Perform substitution transformation on given byte.
+ * 
+ * @param byte Input byte.
+ * @param inv Flag indicating whether to use inverse table.
+ * 
+ * @return Substituted value.
+ */
 static uint8_t sub_byte(uint8_t byte, bool inv)
 {
@@ -208 +216 @@
         
         if(!inv) {
-                return sub_byte_array[i][j];
+                return sbox[i][j];
         } else {
-                return inv_sub_byte_array[i][j];
-        }
-}
-
+                return inv_sbox[i][j];
+        }
+}
+
+/**
+ * Perform substitution transformation on state table.
+ * 
+ * @param state State table to be modified.
+ * @param inv Flag indicating whether to use inverse table.
+ */
 static void sub_bytes(uint8_t state[ELEMS][ELEMS], bool inv)
 {
@@ -226 +240 @@
 }
 
+/**
+ * Perform shift rows transformation on state table.
+ * 
+ * @param state State table to be modified.
+ */
 static void shift_rows(uint8_t state[ELEMS][ELEMS])
 {
@@ -237 +256 @@
 }
 
+/**
+ * Perform inverted shift rows transformation on state table.
+ * 
+ * @param state State table to be modified.
+ */
 static void inv_shift_rows(uint8_t state[ELEMS][ELEMS])
 {
@@ -248 +272 @@
 }
 
+/**
+ * Multiplication in GF(2^8).
+ * 
+ * @param x First factor.
+ * @param y Second factor.
+ * 
+ * @return Multiplication of given factors in GF(2^8).
+ */
 static uint8_t galois_mult(uint8_t x, uint8_t y) {
         uint8_t result = 0;
@@ -265 +297 @@
 }
 
+/**
+ * Perform mix columns transformation on state table.
+ * 
+ * @param state State table to be modified.
+ */
 static void mix_columns(uint8_t state[ELEMS][ELEMS])
 {
@@ -294 +331 @@
 }
 
+/**
+ * Perform inverted mix columns transformation on state table.
+ * 
+ * @param state State table to be modified.
+ */
 static void inv_mix_columns(uint8_t state[ELEMS][ELEMS])
 {
@@ -323 +365 @@
 }
 
+/**
+ * Perform round key transformation on state table.
+ * 
+ * @param state State table to be modified.
+ * @param round_key Round key to be applied on state table.
+ */
 static void add_round_key(uint8_t state[ELEMS][ELEMS], uint32_t *round_key)
 {
@@ -338 +386 @@
 }
 
+/**
+ * Perform substitution transformation on given word.
+ * 
+ * @param byte Input word.
+ * 
+ * @return Substituted word.
+ */
 static uint32_t sub_word(uint32_t word)
 {
@@ -350 +405 @@
 }
 
+/**
+ * Perform left rotation by one byte on given word.
+ * 
+ * @param byte Input word.
+ * 
+ * @return Rotated word.
+ */
 static uint32_t rot_word(uint32_t word)
 {
@@ -355 +417 @@
 }
 
+/**
+ * Key expansion procedure for AES algorithm.
+ * 
+ * @param key Input key.
+ * @param key_exp Result key expansion.
+ */
 static void key_expansion(uint8_t *key, uint32_t *key_exp)
 {
@@ -379 +447 @@
 }
 
+/**
+ * AES-128 encryption algorithm.
+ * 
+ * @param key Input key.
+ * @param input Input data sequence to be encrypted.
+ * @param output Encrypted data sequence.
+ * 
+ * @return EINVAL when input or key not specified, ENOMEM when pointer for 
+ * output is not allocated, otherwise EOK.  
+ */
 int aes_encrypt(uint8_t *key, uint8_t *input, uint8_t *output)
 {
@@ -404 +482 @@
         for(size_t k = 1; k <= ROUNDS; k++) {
                 sub_bytes(state, false);
-                for(size_t i = 0; i < ELEMS; i++) {
-                        for(size_t j = 0; j < ELEMS; j++) {
-                                printf("STATE SUB %d %d : %x\n", i, j, state[i][j]);
-                        }
-                }
                 shift_rows(state);
-                for(size_t i = 0; i < ELEMS; i++) {
-                        for(size_t j = 0; j < ELEMS; j++) {
-                                printf("STATE SHIFT %d %d : %x\n", i, j, state[i][j]);
-                        }
-                }
                 if(k < ROUNDS)
                         mix_columns(state);
@@ -430 +498 @@
 }
 
+/**
+ * AES-128 decryption algorithm.
+ * 
+ * @param key Input key.
+ * @param input Input data sequence to be decrypted.
+ * @param output Decrypted data sequence.
+ * 
+ * @return EINVAL when input or key not specified, ENOMEM when pointer for 
+ * output is not allocated, otherwise EOK.  
+ */
 int aes_decrypt(uint8_t *key, uint8_t *input, uint8_t *output)
 {