Add dependencies/vendor (whatsapp)

vendor/go.mau.fi/libsignal/keys/session/Pair.go

@@ -0,0 +1,43 @@
+// Package session provides a simple structure for session keys, which is
+// a pair of root and chain keys for a session.
+package session
+
+import (
+	"go.mau.fi/libsignal/ecc"
+	"go.mau.fi/libsignal/keys/chain"
+	"go.mau.fi/libsignal/keys/message"
+)
+
+// RootKeyable is an interface for all root key implementations that are part of
+// a session keypair.
+type RootKeyable interface {
+	Bytes() []byte
+	CreateChain(theirRatchetKey ecc.ECPublicKeyable, ourRatchetKey *ecc.ECKeyPair) (*KeyPair, error)
+}
+
+// ChainKeyable is an interface for all chain key implementations that are part of
+// a session keypair.
+type ChainKeyable interface {
+	Key() []byte
+	Index() uint32
+	NextKey() *chain.Key
+	MessageKeys() *message.Keys
+	Current() *chain.Key
+}
+
+// NewKeyPair returns a new session key pair that holds a root and chain key.
+func NewKeyPair(rootKey RootKeyable, chainKey ChainKeyable) *KeyPair {
+	keyPair := KeyPair{
+		RootKey:  rootKey,
+		ChainKey: chainKey,
+	}
+
+	return &keyPair
+}
+
+// KeyPair is a session key pair that holds a single root and chain key pair. These
+// keys are ratcheted after every message sent and every message round trip.
+type KeyPair struct {
+	RootKey  RootKeyable
+	ChainKey ChainKeyable
+}