Port AES to C

c-write/Makefile

@@ -0,0 +1,42 @@
+CC = gcc
+
+# https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
+# https://stackoverflow.com/a/3376483
+CFLAGS = \
+	-Wall \
+	-Wextra \
+	-Wfloat-equal \
+	-Wundef \
+	-Wshadow \
+	-Wpointer-arith \
+	-Wcast-align \
+	-Waggregate-return \
+	-Wcast-qual \
+	-Wswitch-default \
+	-Wswitch-enum \
+	-Wconversion \
+	-Wunreachable-code \
+	-std=c11
+	# -Werror \
+
+NAME = program
+TARGET_DIR = ./target
+
+SRC = $(wildcard lib/*.c)
+
+build:
+	mkdir -p $(TARGET_DIR)
+	$(CC) $(CFLAGS) -o $(TARGET_DIR)/$(NAME) $(SRC) main.c
+
+build_test:
+	mkdir -p $(TARGET_DIR)
+	$(CC) $(CFLAGS) -o $(TARGET_DIR)/$(NAME)_test $(SRC) tests.c
+
+run: build
+	$(TARGET_DIR)/$(NAME)
+
+test: build_test
+	$(TARGET_DIR)/$(NAME)_test
+
+clean:
+	rm -r $(TARGET_DIR)

c-write/lib/aes.c

@@ -0,0 +1,324 @@
+#include "aes_internal.h"
+#include "array.h"
+
+uint8_t S_BOX[256] = {
+    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
+    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
+    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
+    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
+    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
+    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
+    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
+    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
+    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
+    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
+    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
+    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
+    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
+    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
+    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
+    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16,
+};
+
+uint8_t INV_S_BOX[256] = {
+    0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38, 0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB,
+    0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87, 0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB,
+    0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D, 0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,
+    0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2, 0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25,
+    0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92,
+    0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA, 0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,
+    0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A, 0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06,
+    0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02, 0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B,
+    0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA, 0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,
+    0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85, 0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E,
+    0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89, 0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B,
+    0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20, 0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,
+    0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31, 0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F,
+    0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D, 0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF,
+    0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0, 0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,
+    0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26, 0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D,
+};
+
+uint8_t ROUND_CONSTANT[32] = {
+    0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36, 0x6C, 0xD8, 0xAB, 0x4D, 0x9A,
+    0x2F, 0x5E, 0xBC, 0x63, 0xC6, 0x97, 0x35, 0x6A, 0xD4, 0xB3, 0x7D, 0xFA, 0xEF, 0xC5, 0x91, 0x39,
+};
+
+size_t aes__block_get(size_t x, size_t y) {
+    return x * 4 + y;
+}
+
+uint8_t aes__xtime(uint8_t x) {
+    if ((x & 0x80) > 0) {
+        return (uint8_t) ((x << 1) ^ 0x1B) & 0xFF;
+    } else {
+        return (uint8_t) (x << 1) & 0xFF;
+    }
+}
+
+void aes__shift_rows(uint8_t* block, aes_encryption_mode_t mode) {
+    uint8_t* word_original = malloc(sizeof(uint8_t) * WORD_LENGTH);
+
+    for (size_t word_n = 1; word_n < WORD_LENGTH; word_n++) {
+        size_t word_start_idx = word_n * WORD_LENGTH;
+
+        for (size_t word_idx = 0; word_idx < WORD_LENGTH; word_idx++) {
+            word_original[word_idx] = block[word_start_idx + word_idx];
+        }
+
+        for (size_t word_idx = 0; word_idx < WORD_LENGTH; word_idx++) {
+            if (mode == encryption) {
+                block[word_start_idx + word_idx] = word_original[(word_idx + word_n) % WORD_LENGTH];
+            } else {
+                block[word_start_idx + word_idx] = word_original[(word_idx - word_n) % WORD_LENGTH];
+            }
+        }
+    }
+
+    free(word_original);
+}
+
+void aes__mix_words(uint8_t* block, aes_encryption_mode_t mode) {
+    if (mode == decryption) {
+        for (size_t idx = 0; idx < WORD_LENGTH; idx++) {
+            size_t start_idx = aes__block_get(idx, 0);
+
+            uint8_t a = aes__xtime(aes__xtime(block[start_idx] ^ block[start_idx + 2]));
+            uint8_t b = aes__xtime(aes__xtime(block[start_idx + 1] ^ block[start_idx + 3]));
+
+            block[start_idx + 0] ^= a;
+            block[start_idx + 2] ^= a;
+
+            block[start_idx + 1] ^= b;
+            block[start_idx + 3] ^= b;
+        }
+    }
+
+    for (size_t idx = 0; idx < WORD_LENGTH; idx++) {
+        size_t start_idx = aes__block_get(idx, 0);
+
+        uint8_t xor = block[start_idx]
+            ^ block[start_idx + 1]
+            ^ block[start_idx + 2]
+            ^ block[start_idx + 3];
+
+        uint8_t first = block[start_idx];
+
+        for (size_t i = 0; i < 3; i++) {
+            block[start_idx + i] ^= aes__xtime(block[start_idx + i] ^ block[start_idx + i + 1]) ^ xor;
+        }
+
+        block[start_idx + 3] ^= aes__xtime(block[start_idx + 3] ^ first) ^ xor;
+    }
+}
+
+void aes__add_round_key(uint8_t* block, uint8_t* round_key) {
+    xor_arrays(block, round_key, BLOCK_LENGTH);
+}
+
+// NOTE: malloc
+uint8_t* aes__expand_key(uint8_t* key) {
+    // Original key + 10 round keys in an array
+    size_t round_keys_array_size = (ROUNDS + 1) * BLOCK_LENGTH;
+    uint8_t* round_keys = (uint8_t*) malloc(sizeof(uint8_t) * round_keys_array_size);
+    size_t pos = 0;
+    size_t round_constant_idx = 0;
+
+    for (size_t idx = 0; idx < BLOCK_LENGTH; idx++) {
+        round_keys[idx] = key[idx];
+        pos += 1;
+    }
+
+    while (pos < round_keys_array_size) {
+        for (size_t idx = 0; idx < WORD_LENGTH; idx++) {
+            round_keys[idx + pos] = round_keys[idx + pos - WORD_LENGTH];
+        }
+
+        if (pos % BLOCK_LENGTH == 0) {
+            uint8_t first = round_keys[pos];
+            round_keys[pos] = round_keys[pos + 1];
+            round_keys[pos + 1] = round_keys[pos + 2];
+            round_keys[pos + 2] = round_keys[pos + 3];
+            round_keys[pos + 3] = first;
+
+            for (size_t idx = 0; idx < WORD_LENGTH; idx++) {
+                uint8_t value = round_keys[pos + idx];
+                round_keys[pos + idx] = S_BOX[value];
+            }
+
+            round_keys[pos] = round_keys[round_constant_idx];
+            round_constant_idx += 1;
+        }
+
+        uint8_t* previous_word = &round_keys[pos];
+        uint8_t* modifier_word = &round_keys[pos - BLOCK_LENGTH];
+        xor_arrays(previous_word, modifier_word, WORD_LENGTH);
+        pos += WORD_LENGTH;
+    }
+
+    return round_keys;
+}
+
+void aes__encrypt_block(uint8_t* block, uint8_t* round_keys) {
+    aes__add_round_key(block, round_keys);
+    for (size_t round = 1; round <= ROUNDS; round++) {
+        for (size_t idx = 0; idx < BLOCK_LENGTH; idx++) {
+            block[idx] = S_BOX[block[idx]];
+        }
+
+        aes__shift_rows(block, encryption);
+
+        if (round != ROUNDS) {
+            aes__mix_words(block, encryption);
+        }
+
+        aes__add_round_key(block, &round_keys[round * BLOCK_LENGTH]);
+    }
+}
+
+void aes__decrypt_block(uint8_t* block, uint8_t* round_keys) {
+    for (size_t round = ROUNDS; round >= 1; round--) {
+        aes__add_round_key(block, &round_keys[round * BLOCK_LENGTH]);
+
+        if (round != ROUNDS) {
+            aes__mix_words(block, decryption);
+        }
+
+        aes__shift_rows(block, decryption);
+
+        for (size_t idx = 0; idx < BLOCK_LENGTH; idx++) {
+            block[idx] = INV_S_BOX[block[idx]];
+        }
+    }
+
+    aes__add_round_key(block, round_keys);
+}
+
+BOOL aes__is_valid_padding(uint8_t* block) {
+    uint8_t marker = block[BLOCK_LENGTH - 1];
+
+    if (marker == 0) {
+        return FALSE;
+    }
+
+    for (size_t idx = BLOCK_LENGTH - marker; idx < BLOCK_LENGTH; idx++) {
+        if (block[idx] != marker) {
+            return FALSE;
+        }
+    }
+
+    return TRUE;
+}
+
+aes_padded_data_t aes_create_padded_data_container() {
+    aes_padded_data_t out = {
+        .data = NULL,
+        .data_length = 0,
+        .data_length_before_pad = 0,
+        .padded_block = NULL,
+        .length = 0,
+    };
+
+    return out;
+}
+
+// NOTE: malloc
+int aes_pad_data(aes_padded_data_t* ptr, uint8_t* data, size_t length) {
+    if (length == 0) {
+        return 1;
+    }
+
+    uint8_t* padded_block_ptr = malloc(sizeof(uint8_t) * BLOCK_LENGTH);
+    if (padded_block_ptr == NULL) {
+        return 2;
+    }
+
+    ptr->data = data;
+    ptr->data_length = length;
+    ptr->padded_block = padded_block_ptr;
+
+    if (length % BLOCK_LENGTH == 0) {
+        // Fill with marker
+        for (size_t idx = 0; idx < BLOCK_LENGTH; idx++) {
+            padded_block_ptr[idx] = BLOCK_LENGTH;
+        }
+
+        ptr->data_length_before_pad = length;
+    } else {
+        size_t last_block_length = length % BLOCK_LENGTH;
+        uint8_t* last_block = &data[length - last_block_length];
+        size_t marker = BLOCK_LENGTH - last_block_length;
+
+        // Fill with marker
+        for (size_t idx = 0; idx < BLOCK_LENGTH; idx++) {
+            padded_block_ptr[idx] = (uint8_t) (marker & 0xFF);
+        }
+
+        // Insert original data
+        for (size_t idx = 0; idx < last_block_length; idx++) {
+            padded_block_ptr[idx] = last_block[idx];
+        }
+
+        ptr->data_length_before_pad = length - last_block_length;
+    }
+
+    ptr->length = ptr->data_length_before_pad + BLOCK_LENGTH;
+
+    return 0;
+}
+
+int aes_ecb(aes_encryption_mode_t mode, aes_padded_data_t* data, uint8_t* key) {
+    uint8_t* round_keys = aes__expand_key(key);
+
+    for (size_t idx = 0; idx < data->data_length_before_pad; idx += BLOCK_LENGTH) {
+        if (mode == encryption) {
+            aes__encrypt_block(&data->data[idx], round_keys);
+        } else {
+            aes__decrypt_block(&data->data[idx], round_keys);
+        }
+    }
+
+    if (mode == encryption) {
+        aes__encrypt_block(data->padded_block, round_keys);
+    } else {
+        aes__decrypt_block(data->padded_block, round_keys);
+    }
+
+    free(round_keys);
+    return 0;
+}
+
+int aes_cbc(aes_encryption_mode_t mode, aes_padded_data_t* data, uint8_t* key) {
+    uint8_t* round_keys = aes__expand_key(key);
+
+    // TODO: Derive this properly
+    uint8_t* previous_block = malloc(sizeof(uint8_t) * BLOCK_LENGTH * 2);
+    for (size_t idx = 0; idx < BLOCK_LENGTH; idx++) {
+        previous_block[idx] = 0;
+    }
+
+    for (size_t idx = 0; idx < data->data_length_before_pad; idx += BLOCK_LENGTH) {
+        if (mode == encryption) {
+            xor_arrays(&data->data[idx], previous_block, BLOCK_LENGTH);
+            aes__encrypt_block(&data->data[idx], round_keys);
+            clone_array(previous_block, &data->data[idx], BLOCK_LENGTH);
+        } else {
+            clone_array(&previous_block[BLOCK_LENGTH], &data->data[idx], BLOCK_LENGTH);
+            aes__decrypt_block(&data->data[idx], round_keys);
+            xor_arrays(&data->data[idx], previous_block, BLOCK_LENGTH);
+            clone_array(previous_block, &previous_block[BLOCK_LENGTH], BLOCK_LENGTH);
+        }
+    }
+
+    if (mode == encryption) {
+        xor_arrays(data->padded_block, previous_block, BLOCK_LENGTH);
+        aes__encrypt_block(data->padded_block, round_keys);
+    } else {
+        aes__decrypt_block(data->padded_block, round_keys);
+        xor_arrays(data->padded_block, previous_block, BLOCK_LENGTH);
+    }
+
+    free(previous_block);
+    free(round_keys);
+    return 0;
+}

c-write/lib/aes.h

@@ -0,0 +1,33 @@
+#ifndef AES_H_
+#define AES_H_
+
+#include <stdlib.h>
+
+#define BLOCK_LENGTH 16
+
+typedef struct aes_padded_data_t {
+    /// @brief original data, unmodified.
+    uint8_t* data;
+    /// @brief the last block, modified with padding added.
+    uint8_t* padded_block;
+
+    /// @brief original length.
+    size_t data_length;
+    /// @brief length when excluding the block to be modified.
+    size_t data_length_before_pad;
+    /// @brief `data_length_before_pad` + BLOCK_LENGTH
+    size_t length;
+} aes_padded_data_t;
+
+aes_padded_data_t aes_create_padded_data_container();
+
+typedef enum aes_encryption_mode_t {
+    encryption,
+    decryption,
+} aes_encryption_mode_t;
+
+int aes_pad_data(aes_padded_data_t* ptr, uint8_t* data, size_t length);
+int aes_ecb(aes_encryption_mode_t mode, aes_padded_data_t* data, uint8_t* key);
+int aes_cbc(aes_encryption_mode_t mode, aes_padded_data_t* data, uint8_t* key);
+
+#endif // AES_H_

c-write/lib/aes_internal.h

@@ -0,0 +1,23 @@
+#if !defined(AES_INTERNAL_H_) || !defined(AES_H_)
+#define AES_INTERNAL_H_
+
+#include <stdlib.h>
+
+#include "aes.h"
+
+#define WORD_LENGTH 4
+#define ROUNDS 10
+
+#define BOOL int
+#define TRUE 1
+#define FALSE 0
+
+void aes__shift_rows(uint8_t* block, aes_encryption_mode_t mode);
+uint8_t aes__xtime(uint8_t x);
+void aes__mix_words(uint8_t* block, aes_encryption_mode_t mode);
+uint8_t* aes__expand_key(uint8_t* key);
+void aes__encrypt_block(uint8_t* block, uint8_t* round_keys);
+void aes__decrypt_block(uint8_t* block, uint8_t* round_keys);
+int aes__is_valid_padding(uint8_t* block);
+
+#endif // AES_INTERNAL_H_

c-write/lib/aes_tests.c

@@ -0,0 +1,138 @@
+#include <assert.h>
+#include <stdio.h>
+
+#include "aes_internal.h"
+#include "array.h"
+
+#define TEST_DATA { 72, 101, 114, 101, 32, 105, 115, 32, 115, 111, 109, 101, 32, 116, 101, 120, 116, 32, 105, 110, 32, 97, 115, 99, 105, 105, 32, 115, 105, 110, 99, 101, 32, 116, 104, 101, 115, 101, 32, 97, 114, 101, 32, 97, 108, 108, 32, 98, 121, 116, 101, 115, 0 }
+#define TEST_DATA_LENGTH 53
+#define TEST_BLOCK { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, }
+#define TEST_KEY { 130, 191, 5, 162, 175, 104, 200, 14, 32, 0, 97, 170, 10, 83, 159, 90, }
+
+void aes_test_shift_block() {
+    uint8_t original_data[BLOCK_LENGTH] = TEST_BLOCK;
+    uint8_t test_data[BLOCK_LENGTH] = TEST_BLOCK;
+    uint8_t expected_shift[BLOCK_LENGTH] = {
+        0, 1, 2, 3, 5, 6, 7, 4, 10, 11, 8, 9, 15, 12, 13, 14,
+    };
+
+    aes__shift_rows(test_data, encryption);
+    assert(arrays_eq(test_data, expected_shift, BLOCK_LENGTH));
+
+    aes__shift_rows(test_data, decryption);
+    assert(arrays_eq(test_data, original_data, BLOCK_LENGTH));
+}
+
+void aes_test_xtime() {
+    assert(aes__xtime(84) == 168);
+    assert(aes__xtime(255) == 229);
+    assert(aes__xtime(0) == 0);
+    assert(aes__xtime(240) == 251);
+}
+
+void aes_test_mix_words() {
+    uint8_t test_data[BLOCK_LENGTH] = TEST_BLOCK;
+    uint8_t original_data[BLOCK_LENGTH] = TEST_BLOCK;
+
+    aes__mix_words(test_data, encryption);
+    aes__mix_words(test_data, decryption);
+    assert(arrays_eq(test_data, original_data, BLOCK_LENGTH));
+}
+
+void aes_test_expand_key() {
+    uint8_t test_key[BLOCK_LENGTH] = TEST_KEY;
+    uint8_t expected_round_keys[BLOCK_LENGTH * 11] = {
+        130, 191, 5, 162, 175, 104, 200, 14, 32, 0, 97, 170, 10, 83, 159, 90, 110, 100, 187, 197, 193, 12, 115, 203, 225, 12, 18, 97, 235, 95, 141, 59, 163, 57, 89, 44, 98, 53, 42, 231, 131, 57, 56, 134, 104, 102, 181, 189, 148, 236, 35, 105, 246, 217, 9, 142, 117, 224, 49, 8, 29, 134, 132, 181, 216, 179, 246, 205, 46, 106, 255, 67, 91, 138, 206, 75, 70, 12, 74, 254, 54, 101, 77, 151, 24, 15, 178, 212, 67, 133, 124, 159, 5, 137, 54, 97, 177, 96, 162, 252, 169, 111, 16, 40, 234, 234, 108, 183, 239, 99, 90, 214, 10, 222, 84, 35, 163, 177, 68, 11, 73, 91, 40, 188, 166, 56, 114, 106, 141, 158, 86, 7, 46, 47, 18, 12, 103, 116, 58, 176, 193, 76, 72, 218, 191, 204, 1, 127, 145, 227, 19, 115, 246, 151, 41, 195, 55, 219, 97, 25, 48, 35, 213, 229, 161, 192, 198, 150, 87, 87, 239, 85, 96, 140, 142, 76
+    };
+
+    uint8_t* round_keys = aes__expand_key(test_key);
+
+    assert(arrays_eq(round_keys, expected_round_keys, BLOCK_LENGTH));
+
+    free(round_keys);
+}
+
+void aes_test_block_cipher() {
+    uint8_t test_key[BLOCK_LENGTH] = TEST_KEY;
+    uint8_t* round_keys = aes__expand_key(test_key);
+
+    uint8_t original_data[BLOCK_LENGTH] = TEST_BLOCK;
+    uint8_t test_data[BLOCK_LENGTH] = TEST_BLOCK;
+
+    aes__encrypt_block(test_data, round_keys);
+    aes__decrypt_block(test_data, round_keys);
+
+    assert(arrays_eq(test_data, original_data, BLOCK_LENGTH));
+
+    free(round_keys);
+}
+
+void aes_test_padding_validation() {
+    uint8_t data_valid[16] = {
+        12, 63, 3, 76, 10, 92,
+        10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
+    };
+    assert(aes__is_valid_padding(data_valid) == TRUE);
+
+    uint8_t data_invalid[16] = {
+        12, 63, 3, 76, 10, 92,
+        10, 10, 10, 10, 10, 10, 10, 10, 10, 0,
+    };
+    assert(aes__is_valid_padding(data_invalid) == FALSE);
+
+    uint8_t data_valid_all_pad[16] = {
+        16, 16, 16, 16, 16, 16, 16, 16,
+        16, 16, 16, 16, 16, 16, 16, 16,
+    };
+    assert(aes__is_valid_padding(data_valid_all_pad) == TRUE);
+}
+
+void aes_test_create_padding() {
+    uint8_t data[24] = {
+        12, 63,  3, 76, 10, 92, 34, 11,
+        12, 63,  3, 76, 10, 92, 34, 11,
+
+        12, 63,  3, 76, 10, 92, 34, 11,
+    };
+
+    uint8_t expected_padding[BLOCK_LENGTH] = {
+        12, 63,  3, 76, 10, 92, 34, 11,
+        8 ,  8,  8,  8,  8,  8,  8,  8,
+    };
+
+    aes_padded_data_t padded = aes_create_padded_data_container();
+    int code = aes_pad_data(&padded, data, 24);
+    assert(code == 0);
+    assert(padded.data == data);
+    assert(padded.data_length == 24);
+    assert(padded.data_length_before_pad == 16);
+    assert(padded.length == 32);
+    assert(arrays_eq(padded.padded_block, expected_padding, BLOCK_LENGTH));
+}
+
+// TODO: Doesn't test padded block
+void aes_test_cipher() {
+    uint8_t original[TEST_DATA_LENGTH] = TEST_DATA;
+    uint8_t data[TEST_DATA_LENGTH] = TEST_DATA;
+    uint8_t key[BLOCK_LENGTH] = TEST_KEY;
+
+    aes_padded_data_t padded = aes_create_padded_data_container();
+    int code = aes_pad_data(&padded, data, TEST_DATA_LENGTH);
+    assert(code == 0);
+
+    // ECB
+
+    aes_ecb(encryption, &padded, key);
+    assert(!arrays_eq(padded.data, original, padded.data_length_before_pad));
+
+    aes_ecb(decryption, &padded, key);
+    assert(arrays_eq(padded.data, original, padded.data_length_before_pad));
+
+    // CBC
+
+    aes_cbc(encryption, &padded, key);
+    assert(!arrays_eq(padded.data, original, padded.data_length_before_pad));
+
+    aes_cbc(decryption, &padded, key);
+    assert(arrays_eq(padded.data, original, padded.data_length_before_pad));
+}

c-write/lib/aes_tests.h

@@ -0,0 +1,16 @@
+#ifndef AES_TESTS_H
+#define AES_TESTS_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+void aes_test_shift_block();
+void aes_test_xtime();
+void aes_test_mix_words();
+void aes_test_expand_key();
+void aes_test_block_cipher();
+void aes_test_padding_validation();
+void aes_test_create_padding();
+void aes_test_cipher();
+
+#endif // AES_TESTS_H

c-write/lib/array.c

@@ -0,0 +1,41 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+int arrays_eq(
+    uint8_t* lhs,
+    uint8_t* rhs,
+    size_t length
+) {
+    for (size_t i = 0; i < length; i++) {
+        int cmp = lhs[i] == rhs[i];
+        if (cmp == 0) {
+            return 0;
+        }
+    }
+
+    return 1;
+}
+
+void xor_arrays(uint8_t* target, uint8_t* modifier, size_t length) {
+    for (size_t idx = 0; idx < length; idx++) {
+        target[idx] ^= modifier[idx];
+    }
+}
+
+void clone_array(uint8_t* target, uint8_t* modifier, size_t length) {
+    for (size_t idx = 0; idx < length; idx++) {
+        target[idx] = modifier[idx];
+    }
+}
+
+void print_int_array(uint8_t* array, size_t length) {
+    printf("{ ");
+    for (size_t i = 0; i < length; i++)
+    {
+        printf("%d", array[i]);
+        if (i != (length - 1)) {
+            printf(", ");
+        }
+    }
+    printf(" }");
+}

c-write/lib/array.h

@@ -0,0 +1,12 @@
+#ifndef ARRAY_H_
+#define ARRAY_H_
+
+#include <stdlib.h>
+
+int arrays_eq(uint8_t* lhs, uint8_t* rhs, size_t length);
+void xor_arrays(uint8_t* target, uint8_t* modifier, size_t length);
+void clone_array(uint8_t* target, uint8_t* modifier, size_t length);
+
+void print_int_array(uint8_t* array, size_t length);
+
+#endif // ARRAY_H_

c-write/main.c

@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+int main() {
+    printf("Hi\n");
+}

c-write/tests.c

@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+#include "lib/aes_tests.h"
+
+int main() {
+    aes_test_shift_block();
+    aes_test_xtime();
+    aes_test_mix_words();
+    aes_test_expand_key();
+    aes_test_block_cipher();
+    aes_test_padding_validation();
+    aes_test_create_padding();
+    aes_test_cipher();
+
+    printf("OK\n");
+
+    return 0;
+}