message

type Base64Message []byte

type Curve25519Key [Curve25519KeySize]byte

type DecryptBodyDef struct {
	IV           [IVSize]byte        // The IV to use. This is overkill since the key is unique anyways... anyways
	SharedSecret [SharedKeySize]byte // The shared secret, calculate HMAC and Symmetric Key from this
}

type EncryptBodyDef struct {
	IV           [IVSize]byte        // The IV to use. This is overkill since the key is unique anyways... anyways
	SharedSecret [SharedKeySize]byte // The shared secret, calculate HMAC and Symmetric Key from this
	TotalLength  int                 // Total size of body including padding
	PadToLength  int                 // PadToLength will pad the body to PadToLength size of random padding before adding deterministic padding, if any
	MessageType  byte
}

type EncryptedBody struct {
	Encrypted            []byte           // First element
	RandomPadding        []byte           // Second element
	DeterministicPadding []byte           // Third element
	PadKey               [PadKeySize]byte // Will be set if deterministic padding is appended
	HMACSum              [HMACSize]byte   // The HMAC
}

type KeyPack struct {
	ConstantPubKey   *Curve25519Key // Public key: SenderConstantPubKey
	ConstantPrivKey  *Curve25519Key // Private key of ConstantPubKey
	TemporaryPubKey  *Curve25519Key // Public key: SenderTemporaryPubKey
	TemporaryPrivKey *Curve25519Key // Private key of TemporaryPubKey
}

type Message struct {
	SignatureHeader *[SignHeaderSize]byte // Packet signature header
	Header          *[KeyHeaderSize]byte  // Packed message header
	Body            []byte                // Unpacked body
}

type MetaDataRecieve struct {
	SenderConstantPublicKey   *Curve25519Key      // Public key used by sender
	ReceiveConstantPublicKey  *Curve25519Key      // Constant public key of recipient
	ReceiveTemporaryPublicKey *Curve25519Key      // Temporary public key of recipient
	MessageID                 [MessageIDSize]byte // MessageID as calculated
	MessageType               byte                // MessageType of message
}

type MetaDataSend struct {
	MessageID              [MessageIDSize]byte // MessageID of the message (calculated from header+body)
	PadKey                 *[PadKeySize]byte   // Will be set if deterministic padding is appended and meaningful
	MessageKey             *Curve25519Key      // Will be set if ephemeral recipient keys are used
	ReceiverConstantPubKey *Curve25519Key
}

type Receiver struct {
	SenderPublicKey            *Curve25519Key // Optional. If set, verify for message
	ReceiveConstantPrivateKey  *Curve25519Key // Optional. Will use callback if not set
	ReceiveTemporaryPrivateKey *Curve25519Key // Optional. Will try to generate from ReceiveConstantPrivateKey, then Callback
	// KeyCallBack is an optional function to get private keys. It takes a public key as parameter and expects the private key or nil as return
	KeyCallBack func(*Curve25519Key) *Curve25519Key
	// HashCashBits is the minimum number of hashcash bits required. Will be set to default if missing
	HashCashBits byte
}

type Sender struct {
	Signer                    *SignKeyPair   // Optional, autogenerated when missing
	SenderPrivateKey          *Curve25519Key // Optional. Use ephemeral key if missing
	ReceiveConstantPublicKey  *Curve25519Key // Optional. Constant public key of receiver, ephemeral keys will be used if missing
	ReceiveTemporaryPublicKey *Curve25519Key // MUST be set IF ReceiveConstantPublicKey is set
	// TotalLength is the total size of body including padding.
	// Set to default if missing if 0
	TotalLength int
	// PadToLength will pad the body to PadToLength size of random padding before adding deterministic padding, if any.
	// Set to default if missing if 0
	PadToLength int
	// HashCashBits is the minimum number of hashcash bits required. Will be set to default if missing
	HashCashBits byte
}

type SignKeyPair struct {
	PublicKey  *[SignerPubKeySize]byte
	PrivateKey *[ed25519.PrivateKeySize]byte
	Nonce      [hashcash.NonceSize]byte // HashCash nonce
	Bits       byte                     // Bits in hashcash
}

type SignatureDetails struct {
	MsgID         [MessageIDSize]byte      // MsgID of the message (sha256(KeyHeader|Body))
	PublicKey     [SignerPubKeySize]byte   // Public key of signer
	HashCashNonce [hashcash.NonceSize]byte // The HashCash nonce
	HashCashBits  byte                     // HashCash bits
}