Version v0.2.12 - Edited build.sh

README.md

@@ -1,4 +1,4 @@
-# OTP Cipher - One Time Pad Implementation
+r# OTP Cipher - One Time Pad Implementation
 
 A secure one-time pad (OTP) cipher implementation in C with automatic versioning system.
 
@@ -199,3 +199,4 @@ When contributing:
 1. The version will automatically increment on builds
 2. For major features, consider manually creating minor version tags
 3. Generated version files (`src/version.*`, `VERSION`) should not be committed
+# Test change

build.sh

@@ -50,6 +50,32 @@ increment_version() {
     print_status "Current version: $LATEST_TAG"
     print_status "New version: $NEW_VERSION"
     
+    # Stage all changes
+    if git add . 2>/dev/null; then
+        print_success "Staged all changes"
+    else
+        print_warning "Failed to stage changes (maybe not a git repository)"
+    fi
+    
+    # Prompt for commit message
+    echo ""
+    print_status "Please enter a meaningful commit message for version $NEW_VERSION:"
+    echo -n "> "
+    read -r COMMIT_MESSAGE
+    
+    # Check if user provided a message
+    if [[ -z "$COMMIT_MESSAGE" ]]; then
+        print_warning "No commit message provided. Using default message."
+        COMMIT_MESSAGE="Version $NEW_VERSION - Automatic version increment"
+    fi
+    
+    # Commit changes with user-provided message
+    if git commit -m "Version $NEW_VERSION - $COMMIT_MESSAGE" 2>/dev/null; then
+        print_success "Committed changes for version $NEW_VERSION"
+    else
+        print_warning "Failed to commit changes (maybe no changes to commit or not a git repository)"
+    fi
+    
     # Create new git tag
     if git tag "$NEW_VERSION" 2>/dev/null; then
         print_success "Created new version tag: $NEW_VERSION"

otp.c

@@ -62,20 +62,20 @@ void simple_entropy_mix(unsigned char* urandom_buffer, size_t buffer_size,
 
 // Directory management
 int ensure_pads_directory(void);
-void get_pad_path(const char* hash, char* pad_path, char* state_path);
+void get_pad_path(const char* chksum, char* pad_path, char* state_path);
 
 // Utility functions
 uint64_t parse_size_string(const char* size_str);
 char* find_pad_by_prefix(const char* prefix);
 int list_available_pads(void);
-int show_pad_info(const char* hash);
+int show_pad_info(const char* chksum);
 int get_user_choice(int min, int max);
 void show_progress(uint64_t current, uint64_t total, time_t start_time);
 
 // File operations
-int read_state_offset(const char* pad_hash, uint64_t* offset);
+int read_state_offset(const char* pad_chksum, uint64_t* offset);
-int write_state_offset(const char* pad_hash, uint64_t offset);
+int write_state_offset(const char* pad_chksum, uint64_t offset);
-int calculate_sha256(const char* filename, char* hash_hex);
+int calculate_checksum(const char* filename, char* checksum_hex);
 void xor_checksum_256(const unsigned char* data, size_t len, unsigned char checksum[32]);
 char* custom_base64_encode(const unsigned char* input, int length);
 unsigned char* custom_base64_decode(const char* input, int* output_length);
@@ -101,37 +101,46 @@ int interactive_mode(void) {
     
     while (1) {
         show_main_menu();
-        int choice = get_user_choice(1, 6);
+        char input[10];
+        if (fgets(input, sizeof(input), stdin)) {
+            char choice = toupper(input[0]);
             
             switch (choice) {
-            case 1:
+                case 'G':
                     handle_generate_menu();
                     break;
-            case 2:
+                case 'E':
                     handle_encrypt_menu();
                     break;
-            case 3:
+                case 'D':
                     handle_decrypt_menu();
                     break;
-            case 4:
+                case 'L':
                     list_available_pads();
                     break;
-            case 5: {
+                case 'S': {
-                printf("Enter pad hash (or prefix): ");
+                    printf("Enter pad checksum (or prefix): ");
                     char input[MAX_HASH_LENGTH];
                     if (fgets(input, sizeof(input), stdin)) {
                         input[strcspn(input, "\n")] = 0;
-                    char* hash = find_pad_by_prefix(input);
+                        char* chksum = find_pad_by_prefix(input);
-                    if (hash) {
+                        if (chksum) {
-                        show_pad_info(hash);
+                            show_pad_info(chksum);
-                        free(hash);
+                            free(chksum);
                         }
                     }
                     break;
                 }
-            case 6:
+                case 'X':
                     printf("Goodbye!\n");
                     return 0;
+                default:
+                    printf("Invalid option. Please select G, E, D, L, S, or X.\n");
+                    continue;
+            }
+        } else {
+            printf("Error reading input. Please try again.\n");
+            continue;
         }
         printf("\n");
     }
@@ -153,14 +162,14 @@ int command_line_mode(int argc, char* argv[]) {
     }
     else if (strcmp(argv[1], "encrypt") == 0) {
         if (argc != 3) {
-            printf("Usage: %s encrypt <pad_hash_or_prefix>\n", argv[0]);
+            printf("Usage: %s encrypt <pad_chksum_or_prefix>\n", argv[0]);
             return 1;
         }
         return encrypt_text(argv[2]);
     }
     else if (strcmp(argv[1], "decrypt") == 0) {
         if (argc != 3) {
-            printf("Usage: %s decrypt <pad_hash_or_prefix>\n", argv[0]);
+            printf("Usage: %s decrypt <pad_chksum_or_prefix>\n", argv[0]);
             return 1;
         }
         return decrypt_text(argv[2]);
@@ -176,13 +185,13 @@ int command_line_mode(int argc, char* argv[]) {
 
 void show_main_menu(void) {
     printf("=== Main Menu ===\n");
-    printf("1. Generate new pad\n");
+    printf("\033[4mG\033[0menerate new pad\n");
-    printf("2. Encrypt message\n");
+    printf("\033[4mE\033[0mncrypt message\n");
-    printf("3. Decrypt message\n");
+    printf("\033[4mD\033[0mecrypt message\n");
-    printf("4. List available pads\n");
+    printf("\033[4mL\033[0mist available pads\n");
-    printf("5. Show pad information\n");
+    printf("\033[4mS\033[0mhow pad information\n");
-    printf("6. Exit\n");
+    printf("E\033[4mx\033[0mit\n");
-    printf("\nSelect option (1-6): ");
+    printf("\nSelect option: ");
 }
 
 int handle_generate_menu(void) {
@@ -233,7 +242,7 @@ int handle_encrypt_menu(void) {
         return 1;
     }
     
-    printf("\nEnter pad selection (number, hash, or prefix): ");
+    printf("\nEnter pad selection (number, chksum, or prefix): ");
     char input[MAX_HASH_LENGTH];
     if (!fgets(input, sizeof(input), stdin)) {
         printf("Error: Failed to read input\n");
@@ -246,7 +255,7 @@ int handle_encrypt_menu(void) {
 
 int handle_decrypt_menu(void) {
     printf("\n=== Decrypt Message ===\n");
-    return decrypt_text(NULL);  // No pad selection needed - hash comes from message
+    return decrypt_text(NULL);  // No pad selection needed - chksum comes from message
 }
 
 uint64_t parse_size_string(const char* size_str) {
@@ -307,7 +316,7 @@ char* find_pad_by_prefix(const char* prefix) {
         int current = 0;
         rewinddir(dir);
         while ((entry = readdir(dir)) != NULL && match_count == 0) {
-            if (strstr(entry->d_name, ".pad") && strlen(entry->d_name) == 68) { // 64 char hash + ".pad"
+            if (strstr(entry->d_name, ".pad") && strlen(entry->d_name) == 68) { // 64 char chksum + ".pad"
                 current++;
                 if (current == selection) {
                     matches[match_count] = malloc(65);
@@ -368,15 +377,15 @@ int list_available_pads(void) {
     int count = 0;
     
     printf("Available pads:\n");
-    printf("%-4s %-20s %-12s %-12s %-8s\n", "No.", "Hash (first 16 chars)", "Size", "Used", "% Used");
+    printf("%-4s %-20s %-12s %-12s %-8s\n", "No.", "ChkSum (first 16 chars)", "Size", "Used", "% Used");
     printf("%-4s %-20s %-12s %-12s %-8s\n", "---", "-------------------", "----------", "----------", "------");
     
     while ((entry = readdir(dir)) != NULL) {
         if (strstr(entry->d_name, ".pad") && strlen(entry->d_name) == 68) {
             count++;
-            char hash[65];
+            char chksum[65];
-            strncpy(hash, entry->d_name, 64);
+            strncpy(chksum, entry->d_name, 64);
-            hash[64] = '\0';
+            chksum[64] = '\0';
             
             // Get pad file size
             char full_path[300]; // Increased buffer size to accommodate longer paths
@@ -385,7 +394,7 @@ int list_available_pads(void) {
             if (stat(full_path, &st) == 0) {
                 // Get used bytes from state
                 uint64_t used_bytes;
-                read_state_offset(hash, &used_bytes);
+                read_state_offset(chksum, &used_bytes);
                 
                 // Format sizes
                 char size_str[32], used_str[32];
@@ -415,7 +424,7 @@ int list_available_pads(void) {
                 // Calculate percentage
                 double percentage = (double)used_bytes / st.st_size * 100.0;
                 
-                printf("%-4d %-20.16s %-12s %-12s %.1f%%\n", count, hash, size_str, used_str, percentage);
+                printf("%-4d %-20.16s %-12s %-12s %.1f%%\n", count, chksum, size_str, used_str, percentage);
             }
         }
     }
@@ -429,24 +438,24 @@ int list_available_pads(void) {
     return count;
 }
 
-int show_pad_info(const char* hash) {
+int show_pad_info(const char* chksum) {
     char pad_filename[MAX_HASH_LENGTH + 10];
     char state_filename[MAX_HASH_LENGTH + 10];
     
-    snprintf(pad_filename, sizeof(pad_filename), "%s.pad", hash);
+    snprintf(pad_filename, sizeof(pad_filename), "%s.pad", chksum);
-    snprintf(state_filename, sizeof(state_filename), "%s.state", hash);
+    snprintf(state_filename, sizeof(state_filename), "%s.state", chksum);
     
     struct stat st;
     if (stat(pad_filename, &st) != 0) {
-        printf("Pad not found: %s\n", hash);
+        printf("Pad not found: %s\n", chksum);
         return 1;
     }
     
     uint64_t used_bytes;
-    read_state_offset(hash, &used_bytes);
+    read_state_offset(chksum, &used_bytes);
     
     printf("=== Pad Information ===\n");
-    printf("Hash: %s\n", hash);
+    printf("ChkSum: %s\n", chksum);
     printf("File: %s\n", pad_filename);
     
     double size_gb = (double)st.st_size / (1024.0 * 1024.0 * 1024.0);
@@ -496,7 +505,7 @@ int generate_pad(uint64_t size_bytes, int display_progress) {
     char temp_filename[32];
     char pad_filename[MAX_HASH_LENGTH + 10];
     char state_filename[MAX_HASH_LENGTH + 10];
-    char hash_hex[MAX_HASH_LENGTH];
+    char chksum_hex[MAX_HASH_LENGTH];
     
     // Create temporary filename
     snprintf(temp_filename, sizeof(temp_filename), "temp_%ld.pad", time(NULL));
@@ -559,19 +568,19 @@ int generate_pad(uint64_t size_bytes, int display_progress) {
     fclose(urandom);
     fclose(pad_file);
     
-    // Calculate SHA-256 of the pad file
+    // Calculate XOR checksum of the pad file
-    if (calculate_sha256(temp_filename, hash_hex) != 0) {
+    if (calculate_checksum(temp_filename, chksum_hex) != 0) {
-        printf("Error: Cannot calculate pad hash\n");
+        printf("Error: Cannot calculate pad checksum\n");
         unlink(temp_filename);
         return 1;
     }
     
-    // Rename file to its hash
+    // Rename file to its chksum
-    snprintf(pad_filename, sizeof(pad_filename), "%s.pad", hash_hex);
+    snprintf(pad_filename, sizeof(pad_filename), "%s.pad", chksum_hex);
-    snprintf(state_filename, sizeof(state_filename), "%s.state", hash_hex);
+    snprintf(state_filename, sizeof(state_filename), "%s.state", chksum_hex);
     
     if (rename(temp_filename, pad_filename) != 0) {
-        printf("Error: Cannot rename pad file to hash-based name\n");
+        printf("Error: Cannot rename pad file to chksum-based name\n");
         unlink(temp_filename);
         return 1;
     }
@@ -582,7 +591,7 @@ int generate_pad(uint64_t size_bytes, int display_progress) {
     }
     
     // Initialize state file with offset 0
-    if (write_state_offset(hash_hex, 0) != 0) {
+    if (write_state_offset(chksum_hex, 0) != 0) {
         printf("Error: Failed to create state file\n");
         unlink(pad_filename);
         return 1;
@@ -590,7 +599,7 @@ int generate_pad(uint64_t size_bytes, int display_progress) {
     
     double size_gb = (double)size_bytes / (1024.0 * 1024.0 * 1024.0);
     printf("Generated pad: %s (%.2f GB)\n", pad_filename, size_gb);
-    printf("Pad hash: %s\n", hash_hex);
+    printf("Pad chksum: %s\n", chksum_hex);
     printf("State file: %s\n", state_filename);
     printf("Pad file set to read-only\n");
     
@@ -606,7 +615,7 @@ int generate_pad_with_entropy(uint64_t size_bytes, int display_progress, int use
     char temp_filename[64];
     char pad_path[MAX_HASH_LENGTH + 20];
     char state_path[MAX_HASH_LENGTH + 20];
-    char hash_hex[MAX_HASH_LENGTH];
+    char chksum_hex[MAX_HASH_LENGTH];
     
     // Create temporary filename
     snprintf(temp_filename, sizeof(temp_filename), "temp_%ld.pad", time(NULL));
@@ -743,15 +752,15 @@ int generate_pad_with_entropy(uint64_t size_bytes, int display_progress, int use
     fclose(urandom);
     fclose(pad_file);
     
-    // Calculate SHA-256 of the pad file
+    // Calculate XOR checksum of the pad file
-    if (calculate_sha256(temp_filename, hash_hex) != 0) {
+    if (calculate_checksum(temp_filename, chksum_hex) != 0) {
-        printf("Error: Cannot calculate pad hash\n");
+        printf("Error: Cannot calculate pad checksum\n");
         unlink(temp_filename);
         return 1;
     }
     
     // Get final paths in pads directory
-    get_pad_path(hash_hex, pad_path, state_path);
+    get_pad_path(chksum_hex, pad_path, state_path);
     
     if (rename(temp_filename, pad_path) != 0) {
         printf("Error: Cannot move pad file to pads directory\n");
@@ -764,11 +773,11 @@ int generate_pad_with_entropy(uint64_t size_bytes, int display_progress, int use
         printf("Warning: Cannot set pad file to read-only\n");
     }
     
-    // Initialize state file with offset 0
+    // Initialize state file with offset 32 (first 32 bytes used for checksum encryption)
     FILE* state_file = fopen(state_path, "wb");
     if (state_file) {
-        uint64_t zero = 0;
+        uint64_t reserved_bytes = 32;
-        fwrite(&zero, sizeof(uint64_t), 1, state_file);
+        fwrite(&reserved_bytes, sizeof(uint64_t), 1, state_file);
         fclose(state_file);
     } else {
         printf("Error: Failed to create state file\n");
@@ -778,7 +787,7 @@ int generate_pad_with_entropy(uint64_t size_bytes, int display_progress, int use
     
     double size_gb = (double)size_bytes / (1024.0 * 1024.0 * 1024.0);
     printf("Generated pad: %s (%.2f GB)\n", pad_path, size_gb);
-    printf("Pad hash: %s\n", hash_hex);
+    printf("Pad checksum: %s\n", chksum_hex);
     printf("State file: %s\n", state_path);
     if (use_keyboard_entropy) {
         printf("Enhanced with keyboard entropy!\n");
@@ -789,37 +798,46 @@ int generate_pad_with_entropy(uint64_t size_bytes, int display_progress, int use
 }
 
 int encrypt_text(const char* pad_identifier) {
-    char* pad_hash = find_pad_by_prefix(pad_identifier);
+    char* pad_chksum = find_pad_by_prefix(pad_identifier);
-    if (!pad_hash) {
+    if (!pad_chksum) {
         return 1;
     }
     
     char input_text[MAX_INPUT_SIZE];
-    char hash_hex[MAX_HASH_LENGTH];
+    char chksum_hex[MAX_HASH_LENGTH];
     uint64_t current_offset;
     
     char pad_path[MAX_HASH_LENGTH + 20];
     char state_path[MAX_HASH_LENGTH + 20];
-    get_pad_path(pad_hash, pad_path, state_path);
+    get_pad_path(pad_chksum, pad_path, state_path);
     
     // Check if pad file exists
     if (access(pad_path, R_OK) != 0) {
         printf("Error: Pad file %s not found\n", pad_path);
-        free(pad_hash);
+        free(pad_chksum);
         return 1;
     }
     
     // Read current offset
-    if (read_state_offset(pad_hash, &current_offset) != 0) {
+    if (read_state_offset(pad_chksum, &current_offset) != 0) {
         printf("Error: Cannot read state file\n");
-        free(pad_hash);
+        free(pad_chksum);
         return 1;
     }
     
-    // Calculate SHA-256 of pad file
+    // Ensure we never encrypt before offset 32 (reserved for checksum encryption)
-    if (calculate_sha256(pad_path, hash_hex) != 0) {
+    if (current_offset < 32) {
-        printf("Error: Cannot calculate pad hash\n");
+        printf("Warning: State offset below reserved area, adjusting to 32\n");
-        free(pad_hash);
+        current_offset = 32;
+        if (write_state_offset(pad_chksum, current_offset) != 0) {
+            printf("Warning: Failed to update state file\n");
+        }
+    }
+    
+    // Calculate XOR checksum of pad file
+    if (calculate_checksum(pad_path, chksum_hex) != 0) {
+        printf("Error: Cannot calculate pad checksum\n");
+        free(pad_chksum);
         return 1;
     }
     
@@ -829,7 +847,7 @@ int encrypt_text(const char* pad_identifier) {
     
     if (fgets(input_text, sizeof(input_text), stdin) == NULL) {
         printf("Error: Failed to read input\n");
-        free(pad_hash);
+        free(pad_chksum);
         return 1;
     }
     
@@ -842,7 +860,7 @@ int encrypt_text(const char* pad_identifier) {
     
     if (input_len == 0) {
         printf("Error: No input provided\n");
-        free(pad_hash);
+        free(pad_chksum);
         return 1;
     }
     
@@ -850,7 +868,7 @@ int encrypt_text(const char* pad_identifier) {
     struct stat pad_stat;
     if (stat(pad_path, &pad_stat) != 0) {
         printf("Error: Cannot get pad file size\n");
-        free(pad_hash);
+        free(pad_chksum);
         return 1;
     }
     
@@ -858,7 +876,7 @@ int encrypt_text(const char* pad_identifier) {
         printf("Error: Not enough pad space remaining\n");
         printf("Need: %lu bytes, Available: %lu bytes\n", 
                input_len, (uint64_t)pad_stat.st_size - current_offset);
-        free(pad_hash);
+        free(pad_chksum);
         return 1;
     }
     
@@ -866,14 +884,14 @@ int encrypt_text(const char* pad_identifier) {
     FILE* pad_file = fopen(pad_path, "rb");
     if (!pad_file) {
         printf("Error: Cannot open pad file\n");
-        free(pad_hash);
+        free(pad_chksum);
         return 1;
     }
     
     if (fseek(pad_file, current_offset, SEEK_SET) != 0) {
         printf("Error: Cannot seek to offset in pad file\n");
         fclose(pad_file);
-        free(pad_hash);
+        free(pad_chksum);
         return 1;
     }
     
@@ -882,7 +900,7 @@ int encrypt_text(const char* pad_identifier) {
         printf("Error: Cannot read pad data\n");
         free(pad_data);
         fclose(pad_file);
-        free(pad_hash);
+        free(pad_chksum);
         return 1;
     }
     fclose(pad_file);
@@ -897,14 +915,14 @@ int encrypt_text(const char* pad_identifier) {
     char* base64_cipher = custom_base64_encode(ciphertext, input_len);
     
     // Update state offset
-    if (write_state_offset(pad_hash, current_offset + input_len) != 0) {
+    if (write_state_offset(pad_chksum, current_offset + input_len) != 0) {
         printf("Warning: Failed to update state file\n");
     }
     
     // Output in ASCII armor format
-    printf("\n-----BEGIN OTP MESSAGE-----\n");
+    printf("\n\n-----BEGIN OTP MESSAGE-----\n");
     printf("Version: %s\n", get_version());
-    printf("Pad-Hash: %s\n", hash_hex);
+    printf("Pad-ChkSum: %s\n", chksum_hex);
     printf("Pad-Offset: %lu\n", current_offset);
     printf("\n");
     
@@ -914,24 +932,24 @@ int encrypt_text(const char* pad_identifier) {
         printf("%.64s\n", base64_cipher + i);
     }
     
-    printf("-----END OTP MESSAGE-----\n\n");
+    printf("-----END OTP MESSAGE-----\n\n\n");
     
     // Cleanup
     free(pad_data);
     free(ciphertext);
     free(base64_cipher);
-    free(pad_hash);
+    free(pad_chksum);
     
     return 0;
 }
 
 int decrypt_text(const char* pad_identifier) {
-    // For command line mode, pad_identifier is ignored - we'll get the hash from the message
+    // For command line mode, pad_identifier is ignored - we'll get the chksum from the message
     (void)pad_identifier; // Suppress unused parameter warning
     
     char line[MAX_LINE_LENGTH];
-    char stored_hash[MAX_HASH_LENGTH];
+    char stored_chksum[MAX_HASH_LENGTH];
-    char current_hash[MAX_HASH_LENGTH];
+    char current_chksum[MAX_HASH_LENGTH];
     uint64_t pad_offset;
     char base64_data[MAX_INPUT_SIZE * 2] = {0};
     int in_data_section = 0;
@@ -954,9 +972,9 @@ int decrypt_text(const char* pad_identifier) {
         
         if (!found_begin) continue;
         
-        if (strncmp(line, "Pad-Hash: ", 10) == 0) {
+        if (strncmp(line, "Pad-ChkSum: ", 12) == 0) {
-            strncpy(stored_hash, line + 10, 64);
+            strncpy(stored_chksum, line + 12, 64);
-            stored_hash[64] = '\0';
+            stored_chksum[64] = '\0';
         }
         else if (strncmp(line, "Pad-Offset: ", 12) == 0) {
             pad_offset = strtoull(line + 12, NULL, 10);
@@ -974,29 +992,29 @@ int decrypt_text(const char* pad_identifier) {
         return 1;
     }
     
-    // Now we have the pad hash from the message, construct filename
+    // Now we have the pad chksum from the message, construct filename
     char pad_path[MAX_HASH_LENGTH + 20];
     char state_path[MAX_HASH_LENGTH + 20];
-    get_pad_path(stored_hash, pad_path, state_path);
+    get_pad_path(stored_chksum, pad_path, state_path);
     
     // Check if we have this pad
     if (access(pad_path, R_OK) != 0) {
-        printf("Error: Required pad not found: %s\n", stored_hash);
+        printf("Error: Required pad not found: %s\n", stored_chksum);
         printf("Available pads:\n");
         list_available_pads();
         return 1;
     }
     
     // Verify pad integrity
-    if (calculate_sha256(pad_path, current_hash) != 0) {
+    if (calculate_checksum(pad_path, current_chksum) != 0) {
-        printf("Error: Cannot calculate current pad hash\n");
+        printf("Error: Cannot calculate current pad checksum\n");
         return 1;
     }
     
-    if (strcmp(stored_hash, current_hash) != 0) {
+    if (strcmp(stored_chksum, current_chksum) != 0) {
         printf("Warning: Pad integrity check failed!\n");
-        printf("Expected: %s\n", stored_hash);
+        printf("Expected: %s\n", stored_chksum);
-        printf("Current:  %s\n", current_hash);
+        printf("Current:  %s\n", current_chksum);
         printf("Continue anyway? (y/N): ");
         fflush(stdout);
         
@@ -1060,9 +1078,9 @@ int decrypt_text(const char* pad_identifier) {
     return 0;
 }
 
-int read_state_offset(const char* pad_hash, uint64_t* offset) {
+int read_state_offset(const char* pad_chksum, uint64_t* offset) {
     char state_filename[MAX_HASH_LENGTH + 20];
-    snprintf(state_filename, sizeof(state_filename), "%s/%s.state", PADS_DIR, pad_hash);
+    snprintf(state_filename, sizeof(state_filename), "%s/%s.state", PADS_DIR, pad_chksum);
     
     FILE* state_file = fopen(state_filename, "rb");
     if (!state_file) {
@@ -1080,9 +1098,9 @@ int read_state_offset(const char* pad_hash, uint64_t* offset) {
     return 0;
 }
 
-int write_state_offset(const char* pad_hash, uint64_t offset) {
+int write_state_offset(const char* pad_chksum, uint64_t offset) {
     char state_filename[MAX_HASH_LENGTH + 20];
-    snprintf(state_filename, sizeof(state_filename), "%s/%s.state", PADS_DIR, pad_hash);
+    snprintf(state_filename, sizeof(state_filename), "%s/%s.state", PADS_DIR, pad_chksum);
     
     FILE* state_file = fopen(state_filename, "wb");
     if (!state_file) {
@@ -1098,7 +1116,7 @@ int write_state_offset(const char* pad_hash, uint64_t offset) {
     return 0;
 }
 
-int calculate_sha256(const char* filename, char* hash_hex) {
+int calculate_checksum(const char* filename, char* checksum_hex) {
     FILE* file = fopen(filename, "rb");
     if (!file) {
         return 1;
@@ -1142,9 +1160,9 @@ int calculate_sha256(const char* filename, char* hash_hex) {
     
     // Convert to hex string (64 characters)
     for (int i = 0; i < 32; i++) {
-        sprintf(hash_hex + (i * 2), "%02x", encrypted_checksum[i]);
+        sprintf(checksum_hex + (i * 2), "%02x", encrypted_checksum[i]);
     }
-    hash_hex[64] = '\0';
+    checksum_hex[64] = '\0';
     
     return 0;
 }
@@ -1231,9 +1249,9 @@ int ensure_pads_directory(void) {
     return 0;
 }
 
-void get_pad_path(const char* hash, char* pad_path, char* state_path) {
+void get_pad_path(const char* chksum, char* pad_path, char* state_path) {
-    snprintf(pad_path, MAX_HASH_LENGTH + 20, "%s/%s.pad", PADS_DIR, hash);
+    snprintf(pad_path, MAX_HASH_LENGTH + 20, "%s/%s.pad", PADS_DIR, chksum);
-    snprintf(state_path, MAX_HASH_LENGTH + 20, "%s/%s.state", PADS_DIR, hash);
+    snprintf(state_path, MAX_HASH_LENGTH + 20, "%s/%s.state", PADS_DIR, chksum);
 }
 
 
@@ -1329,9 +1347,9 @@ void print_usage(const char* program_name) {
     printf("Usage:\n");
     printf("  %s                              - Interactive mode\n", program_name);
     printf("  %s generate <size>              - Generate new pad\n", program_name);
-    printf("  %s encrypt <pad_hash_prefix>    - Encrypt text\n", program_name);
+    printf("  %s encrypt <pad_checksum_prefix> - Encrypt text\n", program_name);
-    printf("  %s decrypt <pad_hash_prefix>    - Decrypt message\n", program_name);
+    printf("  %s decrypt <pad_checksum_prefix> - Decrypt message\n", program_name);
     printf("  %s list                         - List available pads\n", program_name);
     printf("\nSize examples: 1GB, 5TB, 512MB, 2048 (bytes)\n");
-    printf("Pad selection: Full hash, prefix, or number from list\n");
+    printf("Pad selection: Full chksum, prefix, or number from list\n");
 }