Trait SparkSignerEcies

pub trait SparkSignerEcies {
    // Required methods
    fn encrypt_secret_key_with_ecies(
        &self,
        receiver_public_key: &PublicKey,
        pubkey_for_sk_to_encrypt: &PublicKey,
    ) -> Result<Vec<u8>, SparkSdkError>;
    fn decrypt_secret_key_with_ecies<T>(
        &self,
        ciphertext: T,
        network: Network,
    ) -> Result<SecretKey, SparkSdkError>
       where T: AsRef<[u8]>;
}

Trait for ECIES encryption operations in the Spark wallet.

This trait provides methods for encrypting and decrypting secret keys using the ECIES (Elliptic Curve Integrated Encryption Scheme) algorithm. ECIES enables secure key exchange between users in operations like transfers, where the sender needs to securely transmit leaf private keys to the receiver.

The implementation follows standard ECIES practices:

• Generates an ephemeral key pair
• Derives a shared secret using ECDH
• Uses the shared secret to encrypt/decrypt the data
• Provides authenticated encryption to prevent tampering

Required Methods

fn encrypt_secret_key_with_ecies( &self, receiver_public_key: &PublicKey, pubkey_for_sk_to_encrypt: &PublicKey, ) -> Result<Vec<u8>, SparkSdkError>

Encrypts a secret key using the ECIES algorithm.

This method encrypts a secret key so that only the owner of the corresponding private key for receiver_public_key can decrypt it. This is typically used during transfers to securely send leaf private keys to another user.

Arguments

• receiver_public_key - The public key of the recipient who will be able to decrypt the secret key. This is typically the identity public key of the recipient’s wallet.
• pubkey_for_sk_to_encrypt - The public key corresponding to the secret key that will be encrypted. The method will find the secret key in the wallet based on this public key.

Returns

• Ok(Vec<u8>) - The encrypted secret key as a vector of bytes
• Err(SparkSdkError) - If encryption fails, typically because the secret key corresponding to pubkey_for_sk_to_encrypt cannot be found

Security Considerations

The encrypted data contains all necessary information for decryption by the intended recipient, including the ephemeral public key. No pre-shared secrets are required beyond the recipient’s public key.

Example

// Encrypt a leaf secret key for transfer to another user
let encrypted_key = signer.encrypt_secret_key_with_ecies(
    &recipient_pubkey, // The recipient's identity public key
    &leaf_pubkey       // The public key for the leaf secret key to encrypt
)?;

// The encrypted_key can now be safely transmitted to the recipient

fn decrypt_secret_key_with_ecies<T>( &self, ciphertext: T, network: Network, ) -> Result<SecretKey, SparkSdkError>

where T: AsRef<[u8]>,

Decrypts a secret key using the ECIES algorithm.

This method decrypts a secret key that was encrypted with the wallet’s identity public key. This is typically used during transfer receipt to obtain leaf private keys sent by another user.

Arguments

• ciphertext - The encrypted secret key data. Can be any type that implements AsRef<[u8]>, such as Vec<u8> or &[u8].
• network - The Bitcoin network to use, which affects the derivation path for the identity key used in decryption.

Returns

• Ok(SecretKey) - The decrypted secret key
• Err(SparkSdkError) - If decryption fails, typically due to invalid ciphertext or if the wallet doesn’t have the correct identity private key

Security Considerations

This method uses the wallet’s identity private key for decryption. The implementation must ensure that this key is securely managed and that decrypted secret keys are properly protected after decryption.

Example

// Decrypt a secret key received from another user
let decrypted_secret_key = signer.decrypt_secret_key_with_ecies(
    encrypted_key,
    Network::Bitcoin
)?;

// The decrypted_secret_key can now be used (typically inserted into the wallet)

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl SparkSignerEcies for DefaultSigner