TFHE Library

The TFHE functions can be used on encrypted data inside fhEVM. For instance, you could add 2 encrypted states together with TFHE.add(encryptedValue1, encryptedValue2).

To access all the TFHE functions, you can just import the library at the beginning of your solidity code:

pragma solidity ^0.8.20;

import "fhevm@v0.3.0/lib/TFHE.sol";

We recommend to use the same solidity version (for example v0.8.24) throughout your whole project, unless you are using Foundry that can work with multiple solidity versions. In Remix you might want to stick to v0.8.24.

Here's the list of operations:

Name	Function	Operator	Type
Addition	TFHE.add	+	Binary
Subtraction	TFHE.sub	-	Binary
Multiplication	TFHE.mul	*	Binary
Division	TFHE.div	NA	Binary
Remainder	TFHE.rem	NA	Binary
BitAnd	TFHE.and	&	Binary
BitOr	TFHE.or	|	Binary
BitXor	TFHE.xor	^	Binary
Shift Right	TFHE.shr	NA	Binary
Shift Left	TFHE.shl	NA	Binary

And the list of comparisons:

Name	Function	Operator	Type
Equal	TFHE.eq	NA	Binary
Not equal	TFHE.ne	NA	Binary
Greater than or equal	TFHE.ge	NA	Binary
Greater than	TFHE.gt	NA	Binary
Less than or equal	TFHE.le	NA	Binary
Less than	TFHE.lt	NA	Binary
Min	TFHE.min	NA	Binary
Max	TFHE.max	NA	Binary
Neg	TFHE.neg	-	Unary
Not	TFHE.not	~	Unary

The library has a limited support for operator overloading, so far only +, -, *, &, |, ^, -, ~ are supported for all encrypted types.

More information about the supported operations can be found on the Rust FHE library from Zama: TFHE-rs