Most users of the Sequence SDK will not need to interact with cryptographic functions directly.

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Binary Data

We encapsulate binary data using the FBinaryData structs, which is a wrapper around a pointer to a shared byte array TSharedPtr<TArray<uint8>>. Binary data is further subtyped into FUnsizedData, which represents data of any variable size, and TSizedData<TSize>, which represents data of a required byte length TSize. Important cryptographic types of set size, such as 32-byte private keys, are defined as subtypes of TSizedData- for example, we define FPrivateKey : TSizedData<32>. These can also be loaded from hex strings using From(FString Str), such as FPrivateKey::From("0x0...0");. Ensure that the input string is the correct size.

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The ABI

To call contracts on the blockchain, you will need to encode any data you wish to pass as arguments using the ABI. To read more about the ABI and its specification, check out the solidity docs. Our ABI implementation centers around the ABI class in ABI/ABI.h, which provides functions to convert the following types: UInt32, Int32, Bool, FAddress, and FString. Any other data may be transformed directly into TFixedABIArray or TDynamicABIArray for fixed-length and dynamic length arrays respectively, or to TFixedABIData and TDynamicABIData for fixed-length and dynamic length binary data. Once you have your data stored in ABIEncodeable types, you can provide the ABI an array of the type TArray<ABIEncodeable*> to ABI::Encode to receive the binary encoding of the arguments. See `TestABI.cpp for an example.

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Cryptographic Functions

Eth/Crypto.h provides some important ethereum functions for interacting directly with the blockchain: 
// Derives a public key from a private key
FPublicKey GetPublicKey(FPrivateKey PrivateKey);
// Derives an address from the public key
FAddress GetAddress(FPublicKey PublicKey);
// Finds a keccak hash for some binary data
FHash256 GetKeccakHash(FBinaryData &Data);
// Derives contract address from a given sending address and nonce
FAddress GetContractAddress(FAddress Sender, FBlockNonce Nonce);

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Raw Ethereum Transactions

EthTransaction.h contains a struct designed for managing raw ethereum transactions, including functions to sign and hash them. Note that transactions should usually be handled via the Sequence wallet interface, which sends the transactions via the Sequence WAAS.