1 files changed, 99 insertions, 0 deletions
diff --git a/key/keyring.go b/key/keyring.go
new file mode 100644
index 0000000..9448460
--- /dev/null
+++ b/key/keyring.go
@@ -0,0 +1,99 @@
+package key
+
+import (
+	"bytes"
+	"github.com/keybase/saltpack"
+	"slices"
+)
+
+type keyring struct {
+	keyCreator saltpack.EphemeralKeyCreator
+	boxKeys    []BoxKeypair   // list of box keypairs sorted by public key.
+	sigPubKeys []SigPublicKey // sorted list of public verification keys.
+}
+
+func NewKeyring() saltpack.SigncryptKeyring {
+	return new(keyring)
+}
+
+func (ring *keyring) ImportBoxKeypair(pair BoxKeypair) {
+	i, ok := slices.BinarySearchFunc(ring.boxKeys, pair.Public, cmpBoxKeypairPubKey)
+	if ok {
+		return // key already in keyring.
+	}
+	ring.boxKeys = slices.Insert(ring.boxKeys, i, pair)
+}
+
+func (ring *keyring) ImportSigPublicKey(key SigPublicKey) {
+	i, ok := slices.BinarySearchFunc(ring.sigPubKeys, key, cmpSigPublicKey)
+	if ok {
+		return // key already in keyring.
+	}
+	ring.sigPubKeys = slices.Insert(ring.sigPubKeys, i, key)
+}
+
+func (ring *keyring) CreateEphemeralKey() (saltpack.BoxSecretKey, error) {
+	return ring.keyCreator.CreateEphemeralKey()
+}
+
+func (ring *keyring) LookupBoxSecretKey(kids [][]byte) (int, saltpack.BoxSecretKey) {
+	for _, kid := range kids {
+		var pub BoxPublicKey
+		if len(kid) != len(pub) {
+			continue
+		}
+		pub = BoxPublicKey(kid)
+		i, ok := slices.BinarySearchFunc(ring.boxKeys, pub, cmpBoxKeypairPubKey)
+		if ok {
+			return i, ring.boxKeys[i]
+		}
+	}
+	return -1, nil
+}
+
+func (ring *keyring) LookupBoxPublicKey(kid []byte) saltpack.BoxPublicKey {
+	var pub BoxPublicKey
+	if len(kid) != len(pub) {
+		return nil
+	}
+	pub = BoxPublicKey(kid)
+	i, ok := slices.BinarySearchFunc(ring.boxKeys, pub, cmpBoxKeypairPubKey)
+	if !ok {
+		return nil
+	}
+	return ring.boxKeys[i].Public
+}
+
+func (ring *keyring) GetAllBoxSecretKeys() []saltpack.BoxSecretKey {
+	secrets := make([]saltpack.BoxSecretKey, len(ring.boxKeys))
+	for i := range ring.boxKeys {
+		secrets[i] = ring.boxKeys[i]
+	}
+	return secrets
+}
+
+func (ring *keyring) ImportBoxEphemeralKey(kid []byte) saltpack.BoxPublicKey {
+	var pub BoxPublicKey
+	copy(pub[:], kid)
+	return pub
+}
+
+func (ring *keyring) LookupSigningPublicKey(kid []byte) saltpack.SigningPublicKey {
+	if len(kid) != len(SigPublicKey{}) {
+		return nil
+	}
+	key := SigPublicKey(kid)
+	i, ok := slices.BinarySearchFunc(ring.sigPubKeys, key, cmpSigPublicKey)
+	if !ok {
+		return nil // key not in keyring.
+	}
+	return ring.sigPubKeys[i]
+}
+
+func cmpBoxKeypairPubKey(a BoxKeypair, b BoxPublicKey) int {
+	return a.Public.Compare(b)
+}
+
+func cmpSigPublicKey(a, b SigPublicKey) int {
+	return bytes.Compare(a[:], b[:])
+}