diff --git a/CHANGELOG.md b/CHANGELOG.md
index 422bae2..2eabfc7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,17 @@ Format: [Keep a Changelog](https://keepachangelog.com/en/1.1.0/)
 
 ## [Unreleased]
 
+## [0.3.0] — 2026-04-24
+
+### Added
+- `src/keystore.rs` — AES-256-GCM + Argon2id şifreleme; `save_encrypted` / `load_encrypted` / `prompt_password`
+- `nu wallet new`: şifre ister (confirm), private key şifreli JSON olarak `~/.nu/keystore/<label>.key`'e yazar
+- `nu wallet address`: şifre ister, decrypt edip compressed public key basar
+
+### Changed
+- Keystore formatı plaintext hex'ten JSON (`argon2_hash` + `nonce_hex` + `ciphertext_hex`) formatına geçti
+- Eski `.key` dosyaları yeni format ile uyumsuz — `wallet new` ile yeniden oluşturulmalı
+
 ## [0.2.0] — 2026-04-24
 
 ### Added
diff --git a/Cargo.lock b/Cargo.lock
index a0692a4..0888621 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,6 +2,41 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "aead"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d122413f284cf2d62fb1b7db97e02edb8cda96d769b16e443a4f6195e35662b0"
+dependencies = [
+ "crypto-common",
+ "generic-array",
+]
+
+[[package]]
+name = "aes"
+version = "0.8.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b169f7a6d4742236a0a00c541b845991d0ac43e546831af1249753ab4c3aa3a0"
+dependencies = [
+ "cfg-if",
+ "cipher",
+ "cpufeatures",
+]
+
+[[package]]
+name = "aes-gcm"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "831010a0f742e1209b3bcea8fab6a8e149051ba6099432c8cb2cc117dec3ead1"
+dependencies = [
+ "aead",
+ "aes",
+ "cipher",
+ "ctr",
+ "ghash",
+ "subtle",
+]
+
 [[package]]
 name = "anstream"
 version = "1.0.0"
@@ -58,6 +93,18 @@ version = "1.0.102"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f202df86484c868dbad7eaa557ef785d5c66295e41b460ef922eca0723b842c"
 
+[[package]]
+name = "argon2"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c3610892ee6e0cbce8ae2700349fcf8f98adb0dbfbee85aec3c9179d29cc072"
+dependencies = [
+ "base64ct",
+ "blake2",
+ "cpufeatures",
+ "password-hash",
+]
+
 [[package]]
 name = "atomic-waker"
 version = "1.1.2"
@@ -88,6 +135,15 @@ version = "2.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c4512299f36f043ab09a583e57bceb5a5aab7a73db1805848e8fef3c9e8c78b3"
 
+[[package]]
+name = "blake2"
+version = "0.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46502ad458c9a52b69d4d4d32775c788b7a1b85e8bc9d482d92250fc0e3f8efe"
+dependencies = [
+ "digest",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.10.4"
@@ -125,6 +181,16 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "cipher"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "773f3b9af64447d2ce9850330c473515014aa235e6a783b02db81ff39e4a3dad"
+dependencies = [
+ "crypto-common",
+ "inout",
+]
+
 [[package]]
 name = "clap"
 version = "4.6.1"
@@ -231,9 +297,19 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1bfb12502f3fc46cca1bb51ac28df9d618d813cdc3d2f25b9fe775a34af26bb3"
 dependencies = [
  "generic-array",
+ "rand_core",
  "typenum",
 ]
 
+[[package]]
+name = "ctr"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0369ee1ad671834580515889b80f2ea915f23b8be8d0daa4bbaf2ac5c7590835"
+dependencies = [
+ "cipher",
+]
+
 [[package]]
 name = "der"
 version = "0.7.10"
@@ -478,6 +554,16 @@ dependencies = [
  "wasip3",
 ]
 
+[[package]]
+name = "ghash"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0d8a4362ccb29cb0b265253fb0a2728f592895ee6854fd9bc13f2ffda266ff1"
+dependencies = [
+ "opaque-debug",
+ "polyval",
+]
+
 [[package]]
 name = "group"
 version = "0.13.0"
@@ -781,6 +867,15 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "inout"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "879f10e63c20629ecabbb64a8010319738c66a5cd0c29b02d63d272b03751d01"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "ipnet"
 version = "2.12.0"
@@ -927,13 +1022,16 @@ dependencies = [
 name = "nu-cli"
 version = "0.1.0"
 dependencies = [
+ "aes-gcm",
  "anyhow",
+ "argon2",
  "clap",
  "dirs",
  "hex",
  "k256",
  "rand",
  "reqwest",
+ "rpassword",
  "serde",
  "serde_json",
  "tokio",
@@ -951,6 +1049,12 @@ version = "1.70.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
 
+[[package]]
+name = "opaque-debug"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c08d65885ee38876c4f86fa503fb49d7b507c2b62552df7c70b2fce627e06381"
+
 [[package]]
 name = "openssl"
 version = "0.10.78"
@@ -1024,6 +1128,17 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "password-hash"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "346f04948ba92c43e8469c1ee6736c7563d71012b17d40745260fe106aac2166"
+dependencies = [
+ "base64ct",
+ "rand_core",
+ "subtle",
+]
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.2"
@@ -1052,6 +1167,18 @@ version = "0.3.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19f132c84eca552bf34cab8ec81f1c1dcc229b811638f9d283dceabe58c5569e"
 
+[[package]]
+name = "polyval"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d1fe60d06143b2430aa532c94cfe9e29783047f06c0d7fd359a9a51b729fa25"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "opaque-debug",
+ "universal-hash",
+]
+
 [[package]]
 name = "potential_utf"
 version = "0.1.5"
@@ -1218,6 +1345,27 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "rpassword"
+version = "7.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "66d4c8b64f049c6721ec8ccec37ddfc3d641c4a7fca57e8f2a89de509c73df39"
+dependencies = [
+ "libc",
+ "rtoolbox",
+ "windows-sys 0.59.0",
+]
+
+[[package]]
+name = "rtoolbox"
+version = "0.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "50a0e551c1e27e1731aba276dbeaeac73f53c7cd34d1bda485d02bd1e0f36844"
+dependencies = [
+ "libc",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "rustix"
 version = "1.1.4"
@@ -1720,6 +1868,16 @@ version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ebc1c04c71510c7f702b52b7c350734c9ff1295c464a03335b00bb84fc54f853"
 
+[[package]]
+name = "universal-hash"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc1de2c688dc15305988b563c3854064043356019f97a4b46276fe734c4f07ea"
+dependencies = [
+ "crypto-common",
+ "subtle",
+]
+
 [[package]]
 name = "untrusted"
 version = "0.9.0"
@@ -1947,6 +2105,15 @@ dependencies = [
  "windows-targets 0.52.6",
 ]
 
+[[package]]
+name = "windows-sys"
+version = "0.59.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e38bc4d79ed67fd075bcc251a1c39b32a1776bbe92e5bef1f0bf1f8c531853b"
+dependencies = [
+ "windows-targets 0.52.6",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.61.2"
diff --git a/Cargo.toml b/Cargo.toml
index 1b9726d..dcb5889 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,3 +18,6 @@ k256        = { version = "0.13", features = ["ecdsa"] }   # secp256k1
 rand        = "0.8"
 hex         = "0.4"
 dirs        = "5"
+argon2      = "0.5"
+aes-gcm     = "0.10"
+rpassword   = "7"
diff --git a/src/commands/wallet.rs b/src/commands/wallet.rs
index 4a5d76f..a746c57 100644
--- a/src/commands/wallet.rs
+++ b/src/commands/wallet.rs
@@ -3,20 +3,21 @@ use clap::Subcommand;
 use k256::ecdsa::SigningKey;
 use rand::rngs::OsRng;
 
+use crate::keystore;
+
 #[derive(Subcommand)]
 pub enum WalletCmd {
-    /// Generate a new keypair
+    /// Generate a new encrypted keypair
     New {
-        /// Label for the keystore file
         #[arg(long, default_value = "default")]
         label: String,
     },
-    /// Show address for a keystore entry
+    /// Show compressed public key (address) for a keystore entry
     Address {
         #[arg(long, default_value = "default")]
         label: String,
     },
-    /// Send NUT tokens
+    /// Send NUT tokens (stub — Faz 1 tx signing)
     Send {
         #[arg(long)] to:     String,
         #[arg(long)] amount: u64,
@@ -27,29 +28,36 @@ pub enum WalletCmd {
 pub async fn run(cmd: WalletCmd) -> Result<()> {
     match cmd {
         WalletCmd::New { label } => {
-            let key    = SigningKey::random(&mut OsRng);
-            let bytes  = key.to_bytes();
-            let hex_key = hex::encode(bytes);
+            let key       = SigningKey::random(&mut OsRng);
+            let key_bytes = key.to_bytes();
+            let verifying = key.verifying_key();
+            let address   = hex::encode(verifying.to_sec1_bytes());
 
-            let dir = crate::config::keystore_dir();
+            let password = keystore::prompt_password(true)?;
+
+            let dir  = crate::config::keystore_dir();
             std::fs::create_dir_all(&dir)?;
             let path = dir.join(format!("{label}.key"));
-            // Store as hex — Faz 1: add password encryption
-            std::fs::write(&path, &hex_key)?;
 
-            let verifying = key.verifying_key();
-            println!("Created keystore: {}", path.display());
-            println!("Address (pubkey compressed): {}", hex::encode(verifying.to_sec1_bytes()));
+            keystore::save_encrypted(&path, &key_bytes, &password)?;
+
+            println!("Keystore : {}", path.display());
+            println!("Address  : {address}");
+            println!("(Private key encrypted with Argon2id + AES-256-GCM)");
         }
+
         WalletCmd::Address { label } => {
-            let dir  = crate::config::keystore_dir();
-            let raw  = std::fs::read_to_string(dir.join(format!("{label}.key")))?;
-            let bytes = hex::decode(raw.trim())?;
-            let key  = SigningKey::from_bytes(bytes.as_slice().into())?;
+            let dir      = crate::config::keystore_dir();
+            let path     = dir.join(format!("{label}.key"));
+            let password = keystore::prompt_password(false)?;
+
+            let key_bytes = keystore::load_encrypted(&path, &password)?;
+            let key       = SigningKey::from_bytes(key_bytes.as_slice().into())?;
             println!("{}", hex::encode(key.verifying_key().to_sec1_bytes()));
         }
+
         WalletCmd::Send { to, amount, from } => {
-            println!("TODO: nu wallet send --to {to} --amount {amount} (from: {from})");
+            println!("TODO: nu wallet send --to {to} --amount {amount} Shell (from: {from}) — Faz 1");
         }
     }
     Ok(())
diff --git a/src/keystore.rs b/src/keystore.rs
new file mode 100644
index 0000000..7eead45
--- /dev/null
+++ b/src/keystore.rs
@@ -0,0 +1,119 @@
+use aes_gcm::{
+    aead::{Aead, KeyInit},
+    Aes256Gcm, Key, Nonce,
+};
+use anyhow::{bail, Context, Result};
+use argon2::{Argon2, PasswordHasher, PasswordVerifier};
+use argon2::password_hash::{rand_core::OsRng, PasswordHash, SaltString};
+use serde::{Deserialize, Serialize};
+use std::path::Path;
+
+/// On-disk format for an encrypted keystore entry.
+#[derive(Serialize, Deserialize)]
+struct KeystoreFile {
+    /// Argon2id PHC string — contains salt and params
+    argon2_hash: String,
+    /// AES-256-GCM nonce, hex-encoded (12 bytes)
+    nonce_hex:   String,
+    /// AES-256-GCM ciphertext, hex-encoded
+    ciphertext_hex: String,
+}
+
+/// Encrypt `private_key_bytes` with `password`, write to `path`.
+pub fn save_encrypted(path: &Path, private_key_bytes: &[u8], password: &str) -> Result<()> {
+    let salt = SaltString::generate(&mut OsRng);
+    let argon2 = Argon2::default();
+
+    // Derive 32-byte key from password
+    let hash = argon2
+        .hash_password(password.as_bytes(), &salt)
+        .map_err(|e| anyhow::anyhow!("argon2 hash: {e}"))?;
+
+    let derived = derive_aes_key(&hash)?;
+    #[allow(deprecated)]
+    let cipher  = Aes256Gcm::new(Key::<Aes256Gcm>::from_slice(&derived));
+
+    let nonce_bytes: [u8; 12] = {
+        use rand::RngCore;
+        let mut b = [0u8; 12];
+        rand::rngs::OsRng.fill_bytes(&mut b);
+        b
+    };
+    #[allow(deprecated)]
+    let nonce = Nonce::from_slice(&nonce_bytes);
+
+    let ciphertext = cipher
+        .encrypt(nonce, private_key_bytes)
+        .map_err(|e| anyhow::anyhow!("aes-gcm encrypt: {e}"))?;
+
+    let entry = KeystoreFile {
+        argon2_hash:    hash.to_string(),
+        nonce_hex:      hex::encode(nonce_bytes),
+        ciphertext_hex: hex::encode(&ciphertext),
+    };
+
+    let json = serde_json::to_string_pretty(&entry)?;
+    std::fs::write(path, json)?;
+    Ok(())
+}
+
+/// Decrypt the keystore file at `path` using `password`.
+/// Returns raw private key bytes.
+pub fn load_encrypted(path: &Path, password: &str) -> Result<Vec<u8>> {
+    let json = std::fs::read_to_string(path)
+        .with_context(|| format!("keystore not found: {}", path.display()))?;
+
+    let entry: KeystoreFile = serde_json::from_str(&json)
+        .with_context(|| format!("invalid keystore format: {}", path.display()))?;
+
+    let hash = PasswordHash::new(&entry.argon2_hash)
+        .map_err(|e| anyhow::anyhow!("argon2 parse: {e}"))?;
+
+    // Verify password — Argon2::default() matches the stored params
+    Argon2::default()
+        .verify_password(password.as_bytes(), &hash)
+        .map_err(|_| anyhow::anyhow!("Wrong password"))?;
+
+    let derived = derive_aes_key(&hash)?;
+    #[allow(deprecated)]
+    let cipher  = Aes256Gcm::new(Key::<Aes256Gcm>::from_slice(&derived));
+
+    let nonce_bytes = hex::decode(&entry.nonce_hex)
+        .context("invalid nonce in keystore")?;
+    let ciphertext = hex::decode(&entry.ciphertext_hex)
+        .context("invalid ciphertext in keystore")?;
+
+    #[allow(deprecated)]
+    let nonce = Nonce::from_slice(&nonce_bytes);
+    cipher
+        .decrypt(nonce, ciphertext.as_slice())
+        .map_err(|_| anyhow::anyhow!("Decryption failed — wrong password or corrupted keystore"))
+}
+
+/// Prompt for password (no echo), confirm if `confirm = true`.
+pub fn prompt_password(confirm: bool) -> Result<String> {
+    let password = rpassword::prompt_password("Keystore password: ")?;
+    if password.is_empty() {
+        bail!("Password cannot be empty");
+    }
+    if confirm {
+        let confirm = rpassword::prompt_password("Confirm password: ")?;
+        if password != confirm {
+            bail!("Passwords do not match");
+        }
+    }
+    Ok(password)
+}
+
+/// Derives a 32-byte AES key from an Argon2 PHC hash using its output hash bytes.
+fn derive_aes_key(hash: &PasswordHash<'_>) -> Result<[u8; 32]> {
+    // The hash output is stored in the PHC string; re-derive from stored params
+    let output = hash.hash.ok_or_else(|| anyhow::anyhow!("no hash output in PHC string"))?;
+    let bytes = output.as_bytes();
+    if bytes.len() < 32 {
+        bail!("argon2 output too short for AES-256 key");
+    }
+    let mut key = [0u8; 32];
+    key.copy_from_slice(&bytes[..32]);
+    Ok(key)
+}
diff --git a/src/main.rs b/src/main.rs
index 3b11a7c..60bca1b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,6 @@
 mod commands;
 mod config;
+mod keystore;
 mod rpc;
 
 use anyhow::Result;