Crate bellare_micali

Bellare-Micali 1-out-of-2 Oblivious Transfer (OT) Protocol Implementation

This crate provides a secure and efficient implementation of the Bellare-Micali 1-out-of-2 Oblivious Transfer (OT) protocol. The OT protocol is a fundamental cryptographic primitive used in various secure multi-party computations and protocols, including secure voting systems, private information retrieval, and secure two-party computation.

The implementation leverages the Ristretto group for elliptic curve operations, ensuring strong security guarantees and efficient performance.

Features

• Secure OT Protocol: Implements the Bellare-Micali OT protocol with rigorous security measures.
• Batch Processing: Supports batch processing of OT operations for enhanced efficiency.
• Comprehensive Error Handling: Provides detailed error types to facilitate robust error handling.
• Cryptographic Utilities: Includes a suite of cryptographic utility functions essential for protocol operations.
• Modular Design: Organized into distinct modules for clarity, maintainability, and ease of extension.

Modules

• batch: Contains implementations for batch processing of OT operations, allowing multiple OT instances to be handled simultaneously for improved performance.
• crypto: Houses cryptographic utility functions and structures used throughout the protocol, such as random scalar generation and hashing functions.
• error: Defines the OTError enum, encapsulating all possible errors that can occur during the OT protocol execution.
• protocol: Implements the core OT protocol logic, including the OTProtocol struct that manages the protocol’s state and operations.
• types: Defines fundamental types used across the crate, such as Message and Ciphertext, ensuring type safety and clarity.

Re-Exports

For convenience, the crate re-exports several commonly used items, allowing users to access them directly from the crate root without needing to navigate through individual modules.

• OTError: The primary error type for handling OT protocol errors.
• OTProtocol: The main struct managing the OT protocol’s state and operations.
• Message: Represents messages transmitted within the OT protocol.
• BatchOTProtocol: Facilitates batch processing of multiple OT instances.

Example

Below is a simple example demonstrating how to initialize and execute the OT protocol.

use bellare_micali_ot::OTProtocol;
use curve25519_dalek::ristretto::RistrettoPoint;
use rand::rngs::OsRng;
 
fn main() -> Result<(), bellare_micali_ot::OTError> {
    // Initialize the sender
    let mut rng = OsRng;
    let sender = OTProtocol::new_sender(&mut rng)?;
     
    // Initialize the receiver with a choice bit
    let receiver = OTProtocol::new_receiver(&mut rng, true)?;
     
    // Execute the protocol
    let ciphertext = sender.send(&receiver)?;
    let message = receiver.receive(&ciphertext)?;
     
    println!("Received message: {:?}", message.as_bytes());
     
    Ok(())
}

Security Considerations

• Randomness: The protocol relies on cryptographically secure random number generators. Ensure that a secure RNG is used to prevent potential vulnerabilities.
• Key Management: Properly manage and protect all cryptographic keys and scalars to maintain protocol security.
• Dependencies: Keep all dependencies up-to-date to benefit from the latest security patches and improvements.

License

This project is licensed under the MIT License.

Re-exports

pub use crate::error::OTError;

pub use crate::protocol::OTProtocol;

pub use crate::types::Message;

pub use crate::batch::BatchOTProtocol;

Modules

batch

crypto

error

protocol

types