Public Decryption

This document explains how to perform public decryption of FHEVM ciphertexts. Public decryption is required when you want everyone to see the value in a ciphertext, for example the result of private auction. Public decryption is done using the Relayer SDK, which requests the decryption via HTTP endpoint and returns both the cleartext values and a cryptographic proof that can be verified on-chain.

HTTP Public Decrypt

Calling the public decryption endpoint of the Relayer can be done easily using the following code snippet.

// A list of ciphertexts handles to decrypt
const handles = [
  "0x830a61b343d2f3de67ec59cb18961fd086085c1c73ff0000000000aa36a70000",
  "0x98ee526413903d4613feedb9c8fa44fe3f4ed0dd00ff0000000000aa36a70400",
  "0xb837a645c9672e7588d49c5c43f4759a63447ea581ff0000000000aa36a70700",
];

// The list of decrypted values
// {
//  '0x830a61b343d2f3de67ec59cb18961fd086085c1c73ff0000000000aa36a70000': true,
//  '0x98ee526413903d4613feedb9c8fa44fe3f4ed0dd00ff0000000000aa36a70400': 242n,
//  '0xb837a645c9672e7588d49c5c43f4759a63447ea581ff0000000000aa36a70700': '0xfC4382C084fCA3f4fB07c3BCDA906C01797595a8'
// }
const values = instance.publicDecrypt(handles);

On-chain Verification

After obtaining decrypted values via the Relayer SDK, you can verify the decryption proof on-chain using FHE.checkSignatures(). For the complete workflow including on-chain setup with FHE.makePubliclyDecryptable() and verification, please refer to the Public Decryption Solidity Guide.