diff --git a/Cargo.toml b/Cargo.toml
index 13d3861..ee285c5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2021"
 
 [dependencies]
 clap = { version = "4.5.38", features = ["derive"] }
+hex = "0.4.3"
 rand = "0.9.1"
 rug = "1.27.0"
 
diff --git a/src/main.rs b/src/main.rs
index e49b34c..3fe5c0f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,12 +1,13 @@
 mod bootstrapping;
 mod dghv;
 mod dghv_asym;
+mod fileutils;
 mod utils;
 use crate::dghv::{decrypt_bit, encrypt_bit, generate_secret_key};
-use std::path::{Path, PathBuf};
+use crate::dghv_asym::{encrypt_bit_asym, generate_keys};
+use crate::fileutils::{read_privkey, read_pubkey, write_privkey, write_pubkey};
+use clap::{ArgGroup, Args, Parser, Subcommand};
 use rug::Integer;
-use clap::{Parser, Subcommand};
-
 
 #[derive(Parser)]
 #[command(author, version, about, long_about = None)]
@@ -25,26 +26,58 @@ enum Commands {
         size: u32,
     },
     /// Encrypt a single bit
-    Encrypt {
-        /// bit to encrypt (0 or 1)
-        #[clap(short = 'b', long)]
-        bit: u8,
-        /// secret key (hex)
-        #[clap(short = 'k', long)]
-        key: String,
+    Encrypt(EncryptArgs),
+    /// Decrypt a single bit
+    Decrypt(DecryptArgs),
+    /// Generate pair (pubkey, privkey)
+    KeygenPair {
+        /// output path prefix for keys
+        #[arg(short = 'o', long)]
+        path: String,
+        /// security parameter eta (p bit-length)
+        #[clap(short = 's', long, default_value_t = 6400)]
+        size: u32,
         /// noise parameter
         #[clap(short = 'n', long, default_value_t = 80)]
         noise: u32,
+        /// number of public key elements (theta)
+        #[arg(short = 't', long, default_value_t = 10)]
+        theta: usize,
     },
-    /// Decrypt a single bit
-    Decrypt {
-        /// ciphertext to decrypt (hex)
-        #[clap(short = 'c', long)]
-        ciphertext: String,
-        /// secret key (hex)
-        #[clap(short = 'k', long)]
-        key: String,
-    },
+}
+
+#[derive(Args)]
+#[command(group(ArgGroup::new("keysource").required(true).args(&["key", "privkey", "pubkey"])))]
+struct EncryptArgs {
+    /// bit to encrypt
+    #[arg(short = 'b', long)]
+    bit: u8,
+    /// Key as hex string
+    #[arg(short = 'k', long)]
+    key: Option<String>,
+    /// path to private key file
+    #[arg(long)]
+    privkey: Option<String>,
+    /// path to public key file
+    #[arg(long)]
+    pubkey: Option<String>,
+    /// noise parameter
+    #[arg(short = 'n', long, default_value_t = 80)]
+    noise: u32,
+}
+
+#[derive(Args)]
+#[command(group(ArgGroup::new("keysource").required(true).args(&["key", "privkey"])))]
+struct DecryptArgs {
+    /// ciphertext to decrypt (hex-encoded)
+    #[arg(short = 'c', long)]
+    ciphertext: String,
+    /// key as hex string
+    #[arg(short = 'k', long)]
+    key: Option<String>,
+    /// path to private key file
+    #[arg(long)]
+    privkey: Option<String>,
 }
 
 fn main() {
@@ -52,22 +85,47 @@ fn main() {
 
     match cli.command {
         Commands::Keygen { size } => {
-            let sk = generate_secret_key(size as u32);
+            let sk = generate_secret_key(size);
             println!("Secret key (p): {}", sk.to_string_radix(16));
         }
-        Commands::Encrypt { bit, key, noise } => {
-            let p = Integer::from_str_radix(&key, 16)
-                .expect("Invalid secret key: must be hexadecimal integer");
-            let ct = encrypt_bit(bit, &p, noise as u32, noise as u32);
-            println!("Encrypted bit (c): {}", ct.to_string_radix(16));
+        Commands::Encrypt(args) => {
+            let ct = if let Some(pub_path) = args.pubkey {
+                let pk = read_pubkey(pub_path).expect("Failed to load public key");
+                encrypt_bit_asym(args.bit, &pk, args.noise)
+            } else {
+                let p = if let Some(hex_str) = args.key {
+                    Integer::from_str_radix(&hex_str, 16).expect("Invalid key hex")
+                } else {
+                    read_privkey(args.privkey.unwrap())
+                        .expect("Failed to load private key")
+                        .p
+                };
+                encrypt_bit(args.bit, &p, args.noise, args.noise)
+            };
+            println!("Encrypted bit (hex): {}", ct.to_string_radix(16));
         }
-        Commands::Decrypt { ciphertext, key } => {
-            let p = Integer::from_str_radix(&key, 16)
-                .expect("Invalid secret key: must be hexadecimal integer");
-            let ct = Integer::from_str_radix(&ciphertext, 16)
-                .expect("Invalid ciphertext: must be hexadecimal integer");
+        Commands::Decrypt(args) => {
+            let p = if let Some(hex_str) = args.key {
+                Integer::from_str_radix(&hex_str, 16).expect("Invalid key hex")
+            } else {
+                read_privkey(args.privkey.unwrap())
+                    .expect("Failed to load private key")
+                    .p
+            };
+            let ct = Integer::from_str_radix(&args.ciphertext, 16).expect("Invalid ciphertext");
             let res = decrypt_bit(&ct, &p);
             println!("Decrypted bit: {}", res);
         }
+        Commands::KeygenPair {
+            path,
+            size,
+            noise,
+            theta,
+        } => {
+            let (sk, pk) = generate_keys(noise, size, noise, theta);
+            write_privkey(&path, &sk).expect("Failed to write privkey");
+            write_pubkey(&path, &pk).expect("Failed to write pubkey");
+            println!("keys written to {}.[privkey|pubkey]", path);
+        }
     }
 }