Work on making SecretKeys type-safe

I2PKeyTypes.go

@@ -0,0 +1,62 @@
+// i2p_keys.go
+package i2pkeys
+
+import (
+	"crypto"
+	"crypto/ed25519"
+	"errors"
+	"fmt"
+	"io"
+)
+
+var (
+    ErrInvalidKeyType = errors.New("invalid key type")
+    ErrSigningFailed  = errors.New("signing operation failed")
+)
+
+// KeyType represents supported key algorithms
+type KeyType int
+
+const (
+    KeyTypeEd25519 KeyType = iota
+    KeyTypeElgamal
+    // Add other key types as needed
+)
+
+// SecretKeyProvider extends the basic crypto interfaces
+type SecretKeyProvider interface {
+    crypto.Signer
+    Type() KeyType
+    Raw() []byte
+}
+
+// Ed25519SecretKey provides a type-safe wrapper
+type Ed25519SecretKey struct {
+    key ed25519.PrivateKey
+}
+
+func NewEd25519SecretKey(key ed25519.PrivateKey) (*Ed25519SecretKey, error) {
+    if len(key) != ed25519.PrivateKeySize {
+        return nil, fmt.Errorf("%w: invalid Ed25519 key size", ErrInvalidKeyType)
+    }
+    return &Ed25519SecretKey{key: key}, nil
+}
+
+func (k *Ed25519SecretKey) Type() KeyType {
+    return KeyTypeEd25519
+}
+
+func (k *Ed25519SecretKey) Raw() []byte {
+    return k.key
+}
+
+func (k *Ed25519SecretKey) Public() crypto.PublicKey {
+    return k.key.Public()
+}
+
+func (k *Ed25519SecretKey) Sign(rand io.Reader, digest []byte, opts crypto.SignerOpts) ([]byte, error) {
+    if k == nil || len(k.key) != ed25519.PrivateKeySize {
+        return nil, fmt.Errorf("%w: invalid key state", ErrInvalidKeyType)
+    }
+    return k.key.Sign(rand, digest, opts)
+}