/
prekey.go
153 lines (128 loc) · 3.47 KB
/
prekey.go
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package message
import (
"bytes"
"errors"
"fmt"
"google.golang.org/protobuf/proto"
"github.com/RTann/libsignal-go/protocol/curve"
v1 "github.com/RTann/libsignal-go/protocol/generated/v1"
"github.com/RTann/libsignal-go/protocol/identity"
"github.com/RTann/libsignal-go/protocol/internal/pointer"
"github.com/RTann/libsignal-go/protocol/prekey"
)
var _ Ciphertext = (*PreKey)(nil)
// PreKey represents a pre-key message.
type PreKey struct {
version uint8
registrationID uint32
preKeyID *prekey.ID
signedPreKeyID prekey.ID
baseKey curve.PublicKey
identityKey identity.Key
message *Signal
serialized []byte
}
// PreKeyConfig represents the configuration for a PreKey message.
type PreKeyConfig struct {
Version uint8
RegistrationID uint32
PreKeyID *prekey.ID
SignedPreKeyID prekey.ID
BaseKey curve.PublicKey
IdentityKey identity.Key
Message *Signal
}
func NewPreKey(cfg PreKeyConfig) (Ciphertext, error) {
message, err := proto.Marshal(&v1.PreKeySignalMessage{
RegistrationId: &cfg.RegistrationID,
PreKeyId: (*uint32)(cfg.PreKeyID),
SignedPreKeyId: (*uint32)(&cfg.SignedPreKeyID),
BaseKey: cfg.BaseKey.Bytes(),
IdentityKey: cfg.IdentityKey.Bytes(),
Message: cfg.Message.Bytes(),
})
if err != nil {
return nil, err
}
versionPrefix := ((cfg.Version & 0xF) << 4) | CiphertextVersion
serialized := bytes.NewBuffer(make([]byte, 0, 1+len(message)))
serialized.WriteByte(versionPrefix)
serialized.Write(message)
return &PreKey{
version: cfg.Version,
registrationID: cfg.RegistrationID,
preKeyID: cfg.PreKeyID,
signedPreKeyID: cfg.SignedPreKeyID,
baseKey: cfg.BaseKey,
identityKey: cfg.IdentityKey,
message: cfg.Message,
serialized: serialized.Bytes(),
}, nil
}
func NewPreKeyFromBytes(bytes []byte) (Ciphertext, error) {
if len(bytes) == 0 {
return nil, errors.New("message too short")
}
version := bytes[0] >> 4
if int(version) != CiphertextVersion {
return nil, fmt.Errorf("unsupported message version: %d != %d", int(version), CiphertextVersion)
}
var message v1.PreKeySignalMessage
err := proto.Unmarshal(bytes[1:], &message)
if err != nil {
return nil, err
}
baseKey, err := curve.NewPublicKey(message.GetBaseKey())
if err != nil {
return nil, err
}
identityKey, err := identity.NewKey(message.GetIdentityKey())
if err != nil {
return nil, err
}
msg, err := NewSignalFromBytes(message.GetMessage())
if err != nil {
return nil, err
}
var preKeyID *prekey.ID
if message.PreKeyId != nil {
preKeyID = pointer.To(prekey.ID(message.GetPreKeyId()))
}
return &PreKey{
version: version,
registrationID: message.GetRegistrationId(),
preKeyID: preKeyID,
signedPreKeyID: prekey.ID(message.GetSignedPreKeyId()),
baseKey: baseKey,
identityKey: identityKey,
message: msg.(*Signal),
serialized: bytes,
}, nil
}
func (*PreKey) Type() CiphertextType {
return PreKeyType
}
func (p *PreKey) Bytes() []byte {
return p.serialized
}
func (p *PreKey) Version() uint8 {
return p.version
}
func (p *PreKey) RegistrationID() uint32 {
return p.registrationID
}
func (p *PreKey) PreKeyID() *prekey.ID {
return p.preKeyID
}
func (p *PreKey) SignedPreKeyID() prekey.ID {
return p.signedPreKeyID
}
func (p *PreKey) BaseKey() curve.PublicKey {
return p.baseKey
}
func (p *PreKey) IdentityKey() identity.Key {
return p.identityKey
}
func (p *PreKey) Message() *Signal {
return p.message
}