rust_bottle/
tpm.rs

1//! TPM/HSM support for rust-bottle.
2//!
3//! This module provides an interface for using Trusted Platform Modules (TPM)
4//! and Hardware Security Modules (HSM) with rust-bottle's ECDH operations.
5//!
6//! # Example
7//!
8//! ```rust,no_run
9//! use rust_bottle::tpm::ECDHHandler;
10//! use rust_bottle::ecdh::ecdh_encrypt_with_handler;
11//! use rand::rngs::OsRng;
12//!
13//! // Create a TPM handler (implementation depends on your TPM library)
14//! // let tpm_handler = TpmHandler::new()?;
15//!
16//! // Use it for encryption
17//! // let ciphertext = ecdh_encrypt_with_handler(
18//! //     &mut OsRng,
19//! //     b"Secret message",
20//! //     &public_key_bytes,
21//! //     Some(&tpm_handler),
22//! // )?;
23//! ```
24
25use crate::errors::{BottleError, Result};
26
27/// Trait for ECDH operations that can be performed by TPM/HSM backends.
28///
29/// This trait allows custom hardware backends (TPM, HSM, etc.) to provide
30/// ECDH key exchange operations. Implementations should handle the key exchange
31/// using the hardware module and return the shared secret.
32///
33/// This is similar to gobottle's `ECDHHandler` interface.
34///
35/// # Example
36///
37/// ```rust,no_run
38/// use rust_bottle::tpm::ECDHHandler;
39/// use rust_bottle::errors::Result;
40///
41/// struct MyTpmHandler {
42///     // TPM-specific fields
43/// }
44///
45/// impl ECDHHandler for MyTpmHandler {
46///     fn public_key(&self) -> Result<Vec<u8>> {
47///         // Return the public key from TPM
48///         Ok(vec![])
49///     }
50///
51///     fn ecdh(&self, peer_public_key: &[u8]) -> Result<Vec<u8>> {
52///         // Perform ECDH using TPM
53///         Ok(vec![])
54///     }
55/// }
56/// ```
57pub trait ECDHHandler {
58    /// Get the public key associated with this handler.
59    ///
60    /// The public key should be in the same format as the corresponding
61    /// software key type (e.g., 32 bytes for X25519, 65 bytes for P-256).
62    ///
63    /// # Returns
64    ///
65    /// * `Ok(Vec<u8>)` - The public key bytes
66    /// * `Err(BottleError)` - If the key cannot be retrieved
67    fn public_key(&self) -> Result<Vec<u8>>;
68
69    /// Perform ECDH key exchange with a peer's public key.
70    ///
71    /// This function computes the shared secret using the handler's private
72    /// key (stored in TPM/HSM) and the peer's public key.
73    ///
74    /// # Arguments
75    ///
76    /// * `peer_public_key` - The peer's public key bytes
77    ///
78    /// # Returns
79    ///
80    /// * `Ok(Vec<u8>)` - The shared secret bytes
81    /// * `Err(BottleError)` - If the ECDH operation fails
82    fn ecdh(&self, peer_public_key: &[u8]) -> Result<Vec<u8>>;
83}
84
85#[cfg(feature = "tpm")]
86mod tpm_impl {
87    use super::*;
88
89    /// TPM handler implementation using tss-esapi or similar.
90    ///
91    /// This is a placeholder implementation. Users should implement
92    /// `ECDHHandler` for their specific TPM library.
93    ///
94    /// # Example
95    ///
96    /// ```rust,no_run
97    /// use rust_bottle::tpm::{ECDHHandler, TpmHandler};
98    ///
99    /// // Initialize TPM handler
100    /// // let handler = TpmHandler::new()?;
101    ///
102    /// // Get public key
103    /// // let pub_key = handler.public_key()?;
104    ///
105    /// // Perform ECDH
106    /// // let shared_secret = handler.ecdh(&peer_pub_key)?;
107    /// ```
108    pub struct TpmHandler {
109        // TPM-specific fields would go here
110        // This is a placeholder structure
111    }
112
113    impl TpmHandler {
114        /// Create a new TPM handler.
115        ///
116        /// This function initializes a connection to the TPM and loads
117        /// or creates a key for ECDH operations.
118        ///
119        /// # Returns
120        ///
121        /// * `Ok(TpmHandler)` - A new TPM handler
122        /// * `Err(BottleError)` - If TPM initialization fails
123        pub fn new() -> Result<Self> {
124            // Placeholder implementation
125            // In a real implementation, this would:
126            // 1. Connect to the TPM
127            // 2. Load or create an ECDH key
128            // 3. Return the handler
129            Err(BottleError::UnsupportedAlgorithm)
130        }
131    }
132
133    impl ECDHHandler for TpmHandler {
134        fn public_key(&self) -> Result<Vec<u8>> {
135            // Placeholder implementation
136            // In a real implementation, this would retrieve the public key from TPM
137            Err(BottleError::UnsupportedAlgorithm)
138        }
139
140        fn ecdh(&self, _peer_public_key: &[u8]) -> Result<Vec<u8>> {
141            // Placeholder implementation
142            // In a real implementation, this would:
143            // 1. Parse the peer's public key
144            // 2. Use TPM to perform ECDH
145            // 3. Return the shared secret
146            Err(BottleError::UnsupportedAlgorithm)
147        }
148    }
149}
150
151#[cfg(feature = "tpm")]
152pub use tpm_impl::TpmHandler;
153
rust_bottle/tpm.rs

rust_bottle/
tpm.rs
