Transactions

concrete_fhe_toolkit.finance.transactions

Encrypted transaction processing and settlement logic.

transfer

transfer(sender_balance: Any, receiver_balance: Any, amount: Any) -> tuple[Any, Any]

Transfers an amount from one account to another securely under encryption.

If the amount is negative or the sender has insufficient balance, the transfer is silently cancelled (amount becomes 0) without leaking information about the failure.

Parameters:

Name	Type	Description	Default
sender_balance	Any	The encrypted balance of the sender.	required
receiver_balance	Any	The encrypted balance of the receiver.	required
amount	Any	The encrypted integer amount to be processed.	required

Returns:

Type	Description
tuple[Any, Any]	tuple[Any, Any]: A tuple containing the new encrypted sender balance and receiver balance.

Example

from concrete_fhe_toolkit.finance.transactions import transfer

# Inside an FHE circuit
# enc_new_sender_bal, enc_new_receiver_bal = transfer(
#     enc_sender_bal, enc_receiver_bal, enc_transfer_amount
# )

Source code in src/concrete_fhe_toolkit/finance/transactions.py

def transfer(sender_balance: Any, receiver_balance: Any, amount: Any) -> tuple[Any,Any]:
    """Transfers an amount from one account to another securely under encryption.

    If the amount is negative or the sender has insufficient balance, the
    transfer is silently cancelled (amount becomes 0) without leaking 
    information about the failure.

    Args:
        sender_balance (Any): The encrypted balance of the sender.
        receiver_balance (Any): The encrypted balance of the receiver.
        amount (Any): The encrypted integer amount to be processed.

    Returns:
        tuple[Any, Any]: A tuple containing the new encrypted sender balance and receiver balance.

    Example:
        ```python
        from concrete_fhe_toolkit.finance.transactions import transfer

        # Inside an FHE circuit
        # enc_new_sender_bal, enc_new_receiver_bal = transfer(
        #     enc_sender_bal, enc_receiver_bal, enc_transfer_amount
        # )
        ```
    """
    valid = greater_equal(amount, 0) * greater_equal(sender_balance, amount)
    transferred = amount * valid
    return sender_balance - transferred, receiver_balance + transferred