Add dependencies/vendor (whatsapp)

vendor/go.mau.fi/libsignal/keys/message/MessageKey.go

@@ -0,0 +1,91 @@
+// Package message provides a structure for message keys, which are symmetric
+// keys used for the encryption/decryption of Signal messages.
+package message
+
+// DerivedSecretsSize is the size of the derived secrets for message keys.
+const DerivedSecretsSize = 80
+
+// CipherKeyLength is the length of the actual cipher key used for messages.
+const CipherKeyLength = 32
+
+// MacKeyLength is the length of the message authentication code in bytes.
+const MacKeyLength = 32
+
+// IVLength is the length of the initialization vector in bytes.
+const IVLength = 16
+
+// KdfSalt is used as the Salt for message keys to derive secrets using a Key Derivation Function
+const KdfSalt string = "WhisperMessageKeys"
+
+// NewKeys returns a new message keys structure with the given cipherKey, mac, iv, and index.
+func NewKeys(cipherKey, macKey, iv []byte, index uint32) *Keys {
+	messageKeys := Keys{
+		cipherKey: cipherKey,
+		macKey:    macKey,
+		iv:        iv,
+		index:     index,
+	}
+
+	return &messageKeys
+}
+
+// NewKeysFromStruct will return a new message keys object from the
+// given serializeable structure.
+func NewKeysFromStruct(structure *KeysStructure) *Keys {
+	return NewKeys(
+		structure.CipherKey,
+		structure.MacKey,
+		structure.IV,
+		structure.Index,
+	)
+}
+
+// NewStructFromKeys returns a serializeable structure of message keys.
+func NewStructFromKeys(keys *Keys) *KeysStructure {
+	return &KeysStructure{
+		CipherKey: keys.cipherKey,
+		MacKey:    keys.macKey,
+		IV:        keys.iv,
+		Index:     keys.index,
+	}
+}
+
+// KeysStructure is a serializeable structure of message keys.
+type KeysStructure struct {
+	CipherKey []byte
+	MacKey    []byte
+	IV        []byte
+	Index     uint32
+}
+
+// Keys is a structure to hold all the keys for a single MessageKey, including the
+// cipherKey, mac, iv, and index of the chain key. MessageKeys are used to
+// encrypt individual messages.
+type Keys struct {
+	cipherKey []byte
+	macKey    []byte
+	iv        []byte
+	index     uint32
+}
+
+// CipherKey is the key used to produce ciphertext.
+func (k *Keys) CipherKey() []byte {
+	return k.cipherKey
+}
+
+// MacKey returns the message's message authentication code.
+func (k *Keys) MacKey() []byte {
+	return k.macKey
+}
+
+// Iv returns the message keys' initialization vector. The IV is a fixed-size input
+// to a cryptographic primitive.
+func (k *Keys) Iv() []byte {
+	return k.iv
+}
+
+// Index returns the number of times the chain key has been put through a key derivation
+// function to generate this message key.
+func (k *Keys) Index() uint32 {
+	return k.index
+}