Secure RF Communications

import numpy as np
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
import pqcrypto.kem.kyber1024 as kyber

class SecureBeamformer:
    def __init__(self, num_antennas=8, frequency=28e9):
        self.num_antennas = num_antennas
        self.frequency = frequency
        self.wavelength = 3e8 / frequency
        
        # Initialize post-quantum crypto
        self.public_key, self.secret_key = kyber.generate_keypair()
        
    def encrypt_beam_weights(self, weights):
        """Encrypt beamforming weights using post-quantum crypto"""
        # Generate shared secret using Kyber
        ciphertext, shared_secret = kyber.encrypt(self.public_key)
        
        # Use shared secret for AES-GCM encryption
        cipher = Cipher(
            algorithms.AES(shared_secret[:32]),
            modes.GCM(os.urandom(12)),
            backend=default_backend()
        )
        encryptor = cipher.encryptor()
        
        # Encrypt the beamforming weights
        encrypted_weights = encryptor.update(weights.tobytes())
        encrypted_weights += encryptor.finalize()
        
        return encrypted_weights, encryptor.tag, ciphertext
    
    def secure_beamform(self, angle_deg, data):
        """Apply encrypted beamforming to data"""
        # Calculate steering vector
        angle_rad = np.deg2rad(angle_deg)
        d = self.wavelength / 2  # antenna spacing
        
        steering_vector = np.exp(1j * 2 * np.pi * d * 
                                 np.arange(self.num_antennas) * 
                                 np.sin(angle_rad) / self.wavelength)
        
        # Encrypt steering vector
        encrypted_sv, tag, ciphertext = self.encrypt_beam_weights(steering_vector)
        
        # In real implementation, weights would be decrypted at RF frontend
        # For demo, we'll apply beamforming
        beamformed_signal = data @ steering_vector
        
        return beamformed_signal, encrypted_sv

# Example usage
beamformer = SecureBeamformer(num_antennas=8)
test_data = np.random.randn(1000) + 1j * np.random.randn(1000)
secure_signal, encrypted_weights = beamformer.secure_beamform(30, test_data)

module secure_rf_controller #(
    parameter DATA_WIDTH = 256,
    parameter KEY_WIDTH = 256
)(
    input  wire                     clk,
    input  wire                     rst_n,
    
    // Data interface
    input  wire [DATA_WIDTH-1:0]    plaintext_data,
    input  wire                     data_valid,
    output reg  [DATA_WIDTH-1:0]    encrypted_data,
    output reg                      encrypted_valid,
    
    // Crypto interface
    input  wire [KEY_WIDTH-1:0]     encryption_key,
    input  wire                     key_valid,
    
    // RF control interface
    output reg  [7:0]               beam_angle,
    output reg  [15:0]              tx_power,
    output reg                      rf_enable,
    
    // Security status
    output reg                      secure_link_established,
    output reg  [7:0]               security_level
);

    // State machine for secure transmission
    localparam IDLE = 3'b000;
    localparam KEY_EXCHANGE = 3'b001;
    localparam ENCRYPT = 3'b010;
    localparam TRANSMIT = 3'b011;
    localparam VERIFY = 3'b100;
    
    reg [2:0] state, next_state;
    
    // AES-256 instance
    wire [DATA_WIDTH-1:0] aes_out;
    wire aes_done;
    
    aes_256_gcm aes_inst (
        .clk(clk),
        .rst_n(rst_n),
        .plaintext(plaintext_data),
        .key(encryption_key),
        .start(state == ENCRYPT && data_valid),
        .ciphertext(aes_out),
        .done(aes_done)
    );
    
    // Kyber post-quantum crypto instance
    wire [DATA_WIDTH-1:0] kyber_shared_secret;
    wire kyber_done;
    
    kyber_kem kyber_inst (
        .clk(clk),
        .rst_n(rst_n),
        .public_key(encryption_key),
        .start(state == KEY_EXCHANGE && key_valid),
        .shared_secret(kyber_shared_secret),
        .done(kyber_done)
    );
    
    // Beamforming controller
    reg [7:0] optimal_angle;
    reg [15:0] secure_power_level;
    
    always @(posedge clk) begin
        if (!rst_n) begin
            state <= IDLE;
            secure_link_established <= 1'b0;
            security_level <= 8'd0;
        end else begin
            state <= next_state;
            
            case (state)
                KEY_EXCHANGE: begin
                    if (kyber_done) begin
                        secure_link_established <= 1'b1;
                        security_level <= 8'd256; // 256-bit security
                    end
                end
                
                ENCRYPT: begin
                    if (aes_done) begin
                        encrypted_data <= aes_out;
                        encrypted_valid <= 1'b1;
                        
                        // Adjust beamforming for secure transmission
                        beam_angle <= optimal_angle;
                        tx_power <= secure_power_level;
                        rf_enable <= 1'b1;
                    end
                end
                
                TRANSMIT: begin
                    // Monitor link security during transmission
                    if (/* threat_detected */ 1'b0) begin
                        // Adjust beam to null towards threat
                        beam_angle <= beam_angle + 8'd10;
                    end
                end
            endcase
        end
    end
    
    // Next state logic
    always @(*) begin
        next_state = state;
        
        case (state)
            IDLE: begin
                if (key_valid)
                    next_state = KEY_EXCHANGE;
            end
            
            KEY_EXCHANGE: begin
                if (kyber_done)
                    next_state = ENCRYPT;
            end
            
            ENCRYPT: begin
                if (aes_done)
                    next_state = TRANSMIT;
            end
            
            TRANSMIT: begin
                if (!data_valid)
                    next_state = IDLE;
                else if (data_valid && encrypted_valid)
                    next_state = ENCRYPT;
            end
        endcase
    end

endmodule