diff --git a/src/main.rs b/src/main.rs
index a515075..6599932 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,11 +3,14 @@ use std::io::Write;
 use std::path::PathBuf;
 
 use clap::{Parser, Subcommand};
+use leansig::serialization::Serializable;
 use leansig::signature::{
     generalized_xmss::instantiations_poseidon_top_level::lifetime_2_to_the_32::hashing_optimized::SIGTopLevelTargetSumLifetime32Dim64Base8,
     SignatureScheme,
 };
-use serde_json::Value;
+
+// Type alias for the public key type
+type PublicKeyType = <SIGTopLevelTargetSumLifetime32Dim64Base8 as SignatureScheme>::PublicKey;
 
 /// A CLI tool to generate cryptographic keys for hash-based signatures.
 #[derive(Parser, Debug)]
@@ -111,40 +114,27 @@ fn generate_keys(
 }
 
 /// Convert pubkey JSON file to hex string
-/// Reads the JSON file, extracts root and parameter arrays,
-/// converts each u32 to 4 bytes (little-endian), concatenates,
-/// and returns hex string with "0x" prefix
+/// Reads the JSON file, deserializes into PublicKey type using serde,
+/// then uses SSZ serialization (to_bytes) to get canonical form bytes.
+/// Returns hex string with "0x" prefix.
+///
+/// Note: The JSON file contains field elements in Montgomery form (internal representation).
+/// We must use to_bytes() which performs SSZ serialization to get the canonical form
+/// that is expected by from_bytes() during signature verification.
 fn pubkey_json_to_hex(pk_file_path: &PathBuf) -> Result<String, Box<dyn std::error::Error>> {
     // Read JSON file
     let json_content = fs::read_to_string(pk_file_path)?;
-    let json: Value = serde_json::from_str(&json_content)?;
-    
-    // Extract root array (8 u32 integers)
-    let root_array = json["root"]
-        .as_array()
-        .ok_or("Missing or invalid 'root' array")?;
-    
-    // Extract parameter array (5 u32 integers)
-    let param_array = json["parameter"]
-        .as_array()
-        .ok_or("Missing or invalid 'parameter' array")?;
-    
-    // Convert root array to bytes (little-endian)
-    let mut pubkey_bytes = Vec::new();
-    for val in root_array {
-        let num = val.as_u64().ok_or("Invalid number in root array")? as u32;
-        pubkey_bytes.extend_from_slice(&num.to_le_bytes());
-    }
-    
-    // Convert parameter array to bytes (little-endian)
-    for val in param_array {
-        let num = val.as_u64().ok_or("Invalid number in parameter array")? as u32;
-        pubkey_bytes.extend_from_slice(&num.to_le_bytes());
-    }
-    
+
+    // Deserialize into PublicKeyType using serde (this handles Montgomery form)
+    let public_key: PublicKeyType = serde_json::from_str(&json_content)?;
+
+    // Use to_bytes() which uses SSZ serialization (canonical form)
+    // This is the correct format expected by from_bytes() during verification
+    let pubkey_bytes = public_key.to_bytes();
+
     // Convert bytes to hex string with "0x" prefix
     let hex_string = format!("0x{}", hex::encode(&pubkey_bytes));
-    
+
     Ok(hex_string)
 }