diff --git a/crates/ericrfb/src/codec/tight.rs b/crates/ericrfb/src/codec/tight.rs
index 847377b..1d1764c 100644
--- a/crates/ericrfb/src/codec/tight.rs
+++ b/crates/ericrfb/src/codec/tight.rs
@@ -228,11 +228,24 @@ pub fn decode_tight(
         let decompressor = zlib.get_or_init(stream_idx);
 
         let mut output = vec![0u8; total_bytes];
+        let before_out = decompressor.total_out();
         decompressor
-            .decompress(&compressed, &mut output, flate2::FlushDecompress::Sync)
+            .decompress(&compressed, &mut output, flate2::FlushDecompress::None)
             .map_err(|e| {
-                proto::ProtoError::Io(std::io::Error::new(std::io::ErrorKind::InvalidData, e))
+                proto::ProtoError::Io(std::io::Error::new(
+                    std::io::ErrorKind::InvalidData,
+                    format!(
+                        "zlib: {e} (stream {stream_idx}, in={comp_len}, expected_out={total_bytes})"
+                    ),
+                ))
             })?;
+        let produced = (decompressor.total_out() - before_out) as usize;
+        if produced != total_bytes {
+            return Err(proto::ProtoError::Io(std::io::Error::new(
+                std::io::ErrorKind::InvalidData,
+                format!("zlib: produced {produced} bytes, expected {total_bytes}"),
+            )));
+        }
         output
     };
 
diff --git a/crates/ericrfb/src/input.rs b/crates/ericrfb/src/input.rs
new file mode 100644
index 0000000..b27140e
--- /dev/null
+++ b/crates/ericrfb/src/input.rs
@@ -0,0 +1,223 @@
+use std::io::Write;
+
+use crate::proto;
+
+/// e-RIC key scancode from KbdLayout_104pc.java.
+/// Press = scancode | 0x80, release = scancode.
+/// Sent via msg type 4: `[4, code]`.
+pub fn write_key_press(w: &mut impl Write, scancode: u8) -> proto::Result<()> {
+    w.write_all(&[4, scancode | 0x80])?;
+    w.flush()?;
+    Ok(())
+}
+
+pub fn write_key_release(w: &mut impl Write, scancode: u8) -> proto::Result<()> {
+    w.write_all(&[4, scancode])?;
+    w.flush()?;
+    Ok(())
+}
+
+/// Send a complete key tap (press + release).
+pub fn write_key_tap(w: &mut impl Write, scancode: u8) -> proto::Result<()> {
+    write_key_press(w, scancode)?;
+    write_key_release(w, scancode)?;
+    Ok(())
+}
+
+/// Send a hotkey sequence from the applet's HOTKEYCODE params.
+/// Bytes are space-separated hex values, sent raw via msg type 4.
+pub fn write_hotkey_sequence(w: &mut impl Write, hex_str: &str) -> proto::Result<()> {
+    for token in hex_str.split_whitespace() {
+        if let Ok(byte) = u8::from_str_radix(token, 16) {
+            w.write_all(&[4, byte])?;
+        }
+    }
+    w.flush()?;
+    Ok(())
+}
+
+/// Ctrl+Alt+Delete hotkey sequence from the OmniView's HOTKEYCODE_0 param.
+pub const HOTKEY_CTRL_ALT_DEL: &str = "36 f0 37 f0 4e";
+
+// ---------------------------------------------------------------------------
+// JavaScript KeyboardEvent.code → e-RIC scancode mapping
+//
+// Maps browser key codes to KbdLayout_104pc keycodes.
+// keynr == keycode for almost all keys in this layout.
+// ---------------------------------------------------------------------------
+
+/// Map a JavaScript `KeyboardEvent.code` string to an e-RIC scancode.
+/// Returns `None` for unmapped keys.
+pub fn js_code_to_scancode(code: &str) -> Option<u8> {
+    Some(match code {
+        // Function row
+        "Escape" => 0,
+        "F1" => 59,
+        "F2" => 60,
+        "F3" => 61,
+        "F4" => 62,
+        "F5" => 63,
+        "F6" => 64,
+        "F7" => 65,
+        "F8" => 66,
+        "F9" => 67,
+        "F10" => 68,
+        "F11" => 69,
+        "F12" => 70,
+
+        // Number row
+        "Backquote" => 1,
+        "Digit1" => 2,
+        "Digit2" => 3,
+        "Digit3" => 4,
+        "Digit4" => 5,
+        "Digit5" => 6,
+        "Digit6" => 7,
+        "Digit7" => 8,
+        "Digit8" => 9,
+        "Digit9" => 10,
+        "Digit0" => 11,
+        "Minus" => 12,
+        "Equal" => 13,
+        "Backspace" => 14,
+
+        // QWERTY row
+        "Tab" => 15,
+        "KeyQ" => 16,
+        "KeyW" => 17,
+        "KeyE" => 18,
+        "KeyR" => 19,
+        "KeyT" => 20,
+        "KeyY" => 21,
+        "KeyU" => 22,
+        "KeyI" => 23,
+        "KeyO" => 24,
+        "KeyP" => 25,
+        "BracketLeft" => 26,
+        "BracketRight" => 27,
+
+        // Home row
+        "CapsLock" => 28,
+        "KeyA" => 29,
+        "KeyS" => 30,
+        "KeyD" => 31,
+        "KeyF" => 32,
+        "KeyG" => 33,
+        "KeyH" => 34,
+        "KeyJ" => 35,
+        "KeyK" => 36,
+        "KeyL" => 37,
+        "Semicolon" => 38,
+        "Quote" => 39,
+        "Enter" => 40,
+
+        // Bottom row
+        "ShiftLeft" => 41,
+        "Backslash" => 42,
+        "KeyZ" => 43,
+        "KeyX" => 44,
+        "KeyC" => 45,
+        "KeyV" => 46,
+        "KeyB" => 47,
+        "KeyN" => 48,
+        "KeyM" => 49,
+        "Comma" => 50,
+        "Period" => 51,
+        "Slash" => 52,
+        "ShiftRight" => 53,
+
+        // Modifier / bottom row
+        "ControlLeft" => 54,
+        "MetaLeft" => 105,
+        "AltLeft" => 55,
+        "Space" => 56,
+        "AltRight" => 57,
+        "MetaRight" => 106,
+        "ControlRight" => 58,
+
+        // Navigation cluster
+        "PrintScreen" => 71,
+        "ScrollLock" => 72,
+        "Pause" => 73,
+        "Insert" => 75,
+        "Home" => 76,
+        "PageUp" => 77,
+        "Delete" => 78,
+        "End" => 79,
+        "PageDown" => 80,
+
+        // Arrow keys
+        "ArrowUp" => 81,
+        "ArrowLeft" => 82,
+        "ArrowDown" => 83,
+        "ArrowRight" => 84,
+
+        // Numpad
+        "NumLock" => 85,
+        "NumpadDivide" => 86,
+        "NumpadMultiply" => 87,
+        "NumpadSubtract" => 88,
+        "NumpadAdd" => 89,
+        "NumpadEnter" => 98,
+        "Numpad7" => 90,
+        "Numpad8" => 94,
+        "Numpad9" => 99,
+        "Numpad4" => 91,
+        "Numpad5" => 92,
+        "Numpad6" => 93,
+        "Numpad1" => 95,
+        "Numpad2" => 96,
+        "Numpad3" => 97,
+        "Numpad0" => 100,
+        "NumpadDecimal" => 101,
+
+        _ => return None,
+    })
+}
+
+/// Send Ctrl+Alt+Delete via the applet's hotkey sequence.
+pub fn write_ctrl_alt_del(w: &mut impl Write) -> proto::Result<()> {
+    write_hotkey_sequence(w, HOTKEY_CTRL_ALT_DEL)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_key_press_sets_bit7() {
+        let mut buf = Vec::new();
+        write_key_press(&mut buf, 29).unwrap(); // 'A' scancode
+        assert_eq!(buf, [4, 29 | 0x80]);
+    }
+
+    #[test]
+    fn test_key_release_no_bit7() {
+        let mut buf = Vec::new();
+        write_key_release(&mut buf, 29).unwrap();
+        assert_eq!(buf, [4, 29]);
+    }
+
+    #[test]
+    fn test_key_tap() {
+        let mut buf = Vec::new();
+        write_key_tap(&mut buf, 29).unwrap();
+        assert_eq!(buf, [4, 29 | 0x80, 4, 29]);
+    }
+
+    #[test]
+    fn test_hotkey_sequence() {
+        let mut buf = Vec::new();
+        write_hotkey_sequence(&mut buf, "36 f0 37").unwrap();
+        assert_eq!(buf, [4, 0x36, 4, 0xF0, 4, 0x37]);
+    }
+
+    #[test]
+    fn test_js_code_mapping() {
+        assert_eq!(js_code_to_scancode("KeyA"), Some(29));
+        assert_eq!(js_code_to_scancode("Escape"), Some(0));
+        assert_eq!(js_code_to_scancode("ControlLeft"), Some(54));
+        assert_eq!(js_code_to_scancode("Delete"), Some(78));
+        assert_eq!(js_code_to_scancode("Unknown"), None);
+    }
+}
diff --git a/crates/ericrfb/src/lib.rs b/crates/ericrfb/src/lib.rs
index 5feec30..577f1a9 100644
--- a/crates/ericrfb/src/lib.rs
+++ b/crates/ericrfb/src/lib.rs
@@ -1,6 +1,7 @@
 pub mod codec;
 pub mod framebuffer;
 pub mod handshake;
+pub mod input;
 pub mod msg;
 pub mod proto;
 pub mod session;