NEF and Manifest Files

Neo N3 uses the NEF (NEO Executable Format) and Manifest files as a replacement of the AVM and ABI files in Neo Legacy.

When a contract is compiled successfully, the compiler generates both the NEF file and Manifest file. These two files are also needed when you deploy a contract or upgrade a contract.

NEF

The NEF file includes the following fields.

Field	Type	Comment
Magic	uint32	The Magic value of the blockchain.
Compiler	byte[64]	Compiler name and version
Source	byte[64]	The source code address of the contract
Reserve	byte[2]	The field reserved for future extensions. It must be 0.
Tokens	MethodToken[]	Method tokens.
Reserve	byte[2]	The field reserved for future extensions. It must be 0.
Script	Byte[]	The contract script
Checksum	uint32	The first four bytes after two-time SHA256 hashed

Manifest

Before deploying the contract, you need to explicitly declare the contract functions and permissions in the manifest file, which affects the contract behavior when running.

The Manifest file includes the following fields.

Field	Type	Comment
Name	string	Contract name
Groups	ContractGroup[] Consisting of a public key and a signature on the contract hash	Defines a group of trusted contracts. Contracts in a group trusts each other and can be invoked by each other, without prompting the user any warnings. For example, a series of contracts that call each other for a DeFi project. A group is identified by a public key and must has a signature for the contract hash to prove that the contract is included in the group.
SupportedStandards	string[]	Supported NEP standard, equivalent to NEP-10 in Neo Legacy.x
Abi	ContractAbi	NEP-14 (NeoContract ABI) Description of smart contract methods (name, parameters, return value, offset, safe or not), events (name, parameters)
Permissions	ContractPermission[] Consisting of the contract and its method names	This field is an array containing a permission object, which defines other contracts and methods that the contract wants to call. The contract can be ScriptHash, Group, or Permission.Any *. The method is the method name or Permission.Any *. Contracts or methods not declared in the manifest cannot be called by the contract.
Trusts	WildcardContainer<ContractPermissionDescriptor>	Defines other contracts trusted by the contract. The contract can be ScriptHash, Group, or Permission.Any *. If a contract is trusted, the user will not receive any warning message when the contract is called.
Extra	object	Other user-defined data, such as developer, email, URL, contract profile, etc.