Type Alias Nonces 

pub type Nonces<T: Config> = StorageDoubleMap<_GeneratedPrefixForStorageNonces<T>, Blake2_128Concat, H160, Blake2_128Concat, H160, U256, ValueQuery>;

Nonces for permit signatures. Mapping: (verifying_contract, owner_address) => nonce

Uses Blake2_128Concat for the first key to prevent storage collision attacks when the verifying_contract address could be influenced by an attacker.

Note: EIP-2612 specifies uint256 nonce. We store as U256 for compatibility.

Storage type is [StorageDoubleMap] with key1 type H160, key2 type H160 and value type U256.

Aliased Type

pub struct Nonces<T: Config>(/* private fields */);