Version v0.2.75 - Fixed decrypt mode to suppress startup messages for clean pipe operations

otp.c

@@ -81,6 +81,7 @@ int generate_pad(uint64_t size_bytes, int show_progress);
 int generate_pad_with_entropy(uint64_t size_bytes, int show_progress, int use_keyboard_entropy);
 int encrypt_text(const char* pad_identifier, const char* input_text);
 int decrypt_text(const char* pad_identifier, const char* encrypted_message);
+int decrypt_text_silent(const char* pad_identifier, const char* encrypted_message);
 int encrypt_file(const char* pad_identifier, const char* input_file, const char* output_file, int ascii_armor);
 int decrypt_file(const char* input_file, const char* output_file);
 int decrypt_binary_file(FILE* input_fp, const char* output_file);
@@ -137,11 +138,16 @@ int main(int argc, char* argv[]) {
     // Check for piped input first (before any output)
     int is_pipe_mode = (argc == 1 && has_stdin_data());
     
+    // Check for decrypt command with piped input
+    int is_decrypt_pipe = (argc == 2 && 
+                          (strcmp(argv[1], "decrypt") == 0 || strcmp(argv[1], "-d") == 0) && 
+                          has_stdin_data());
+    
     // Check for OTP thumb drive on startup
     char otp_drive_path[512];
     if (detect_otp_thumb_drive(otp_drive_path, sizeof(otp_drive_path))) {
         // Only show messages in interactive/command mode, not pipe mode
-        if (!is_pipe_mode) {
+        if (!is_pipe_mode && !is_decrypt_pipe) {
             printf("Detected OTP thumb drive: %s\n", otp_drive_path);
             printf("Using as default pads directory for this session.\n\n");
         }
@@ -238,6 +244,16 @@ int command_line_mode(int argc, char* argv[]) {
     }
     else if (strcmp(argv[1], "decrypt") == 0 || strcmp(argv[1], "-d") == 0) {
         if (argc == 2) {
+            // Check for piped input first
+            if (has_stdin_data()) {
+                // Piped decrypt mode - read stdin and decrypt silently
+                char* piped_message = read_stdin_text();
+                if (piped_message) {
+                    int result = decrypt_text_silent(NULL, piped_message);
+                    free(piped_message);
+                    return result;
+                }
+            }
             // Interactive mode - no arguments needed
             return decrypt_text(NULL, NULL);
         }
@@ -1599,6 +1615,131 @@ int decrypt_text(const char* pad_identifier, const char* encrypted_message) {
     return 0;
 }
 
+int decrypt_text_silent(const char* pad_identifier, const char* encrypted_message) {
+    // For piped decrypt mode - silent operation with minimal output
+    (void)pad_identifier; // Suppress unused parameter warning
+    
+    char line[MAX_LINE_LENGTH];
+    char stored_chksum[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;
+    
+    if (encrypted_message != NULL) {
+        // Parse provided encrypted message
+        char *message_copy = strdup(encrypted_message);
+        char *line_ptr = strtok(message_copy, "\n");
+        
+        int found_begin = 0;
+        while (line_ptr != NULL) {
+            if (strcmp(line_ptr, "-----BEGIN OTP MESSAGE-----") == 0) {
+                found_begin = 1;
+            }
+            else if (strcmp(line_ptr, "-----END OTP MESSAGE-----") == 0) {
+                break;
+            }
+            else if (found_begin) {
+                if (strncmp(line_ptr, "Pad-ChkSum: ", 12) == 0) {
+                    strncpy(stored_chksum, line_ptr + 12, 64);
+                    stored_chksum[64] = '\0';
+                }
+                else if (strncmp(line_ptr, "Pad-Offset: ", 12) == 0) {
+                    pad_offset = strtoull(line_ptr + 12, NULL, 10);
+                }
+                else if (strlen(line_ptr) == 0) {
+                    in_data_section = 1;
+                }
+                else if (in_data_section) {
+                    strncat(base64_data, line_ptr, sizeof(base64_data) - strlen(base64_data) - 1);
+                }
+            }
+            line_ptr = strtok(NULL, "\n");
+        }
+        free(message_copy);
+        
+        if (!found_begin) {
+            fprintf(stderr, "Error: Invalid message format - missing BEGIN header\n");
+            return 1;
+        }
+    } else {
+        fprintf(stderr, "Error: No encrypted message provided\n");
+        return 1;
+    }
+    
+    // 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_chksum, pad_path, state_path);
+    
+    // Check if we have this pad
+    if (access(pad_path, R_OK) != 0) {
+        fprintf(stderr, "Error: Required pad not found: %s\n", stored_chksum);
+        return 1;
+    }
+    
+    // Verify pad integrity (silent check)
+    if (calculate_checksum(pad_path, current_chksum) != 0) {
+        fprintf(stderr, "Error: Cannot calculate current pad checksum\n");
+        return 1;
+    }
+    
+    if (strcmp(stored_chksum, current_chksum) != 0) {
+        fprintf(stderr, "Error: Pad integrity check failed!\n");
+        return 1;
+    }
+    
+    // Decode base64
+    int ciphertext_len;
+    unsigned char* ciphertext = custom_base64_decode(base64_data, &ciphertext_len);
+    if (!ciphertext) {
+        fprintf(stderr, "Error: Invalid base64 data\n");
+        return 1;
+    }
+    
+    // Read pad data at specified offset
+    FILE* pad_file = fopen(pad_path, "rb");
+    if (!pad_file) {
+        fprintf(stderr, "Error: Cannot open pad file %s\n", pad_path);
+        free(ciphertext);
+        return 1;
+    }
+    
+    if (fseek(pad_file, pad_offset, SEEK_SET) != 0) {
+        fprintf(stderr, "Error: Cannot seek to offset %lu in pad file\n", pad_offset);
+        free(ciphertext);
+        fclose(pad_file);
+        return 1;
+    }
+    
+    unsigned char* pad_data = malloc(ciphertext_len);
+    if (fread(pad_data, 1, ciphertext_len, pad_file) != (size_t)ciphertext_len) {
+        fprintf(stderr, "Error: Cannot read pad data\n");
+        free(ciphertext);
+        free(pad_data);
+        fclose(pad_file);
+        return 1;
+    }
+    fclose(pad_file);
+    
+    // XOR decrypt
+    char* plaintext = malloc(ciphertext_len + 1);
+    for (int i = 0; i < ciphertext_len; i++) {
+        plaintext[i] = ciphertext[i] ^ pad_data[i];
+    }
+    plaintext[ciphertext_len] = '\0';
+    
+    // Output only the decrypted text - no extra messages
+    printf("%s\n", plaintext);
+    
+    // Cleanup
+    free(ciphertext);
+    free(pad_data);
+    free(plaintext);
+    
+    return 0;
+}
+
 int encrypt_file(const char* pad_identifier, const char* input_file, const char* output_file, int ascii_armor) {
     char* pad_chksum = find_pad_by_prefix(pad_identifier);
     if (!pad_chksum) {