Add OpenVPN, TrustTunnel, Sudoku, inbound managers. Fixes

transport/sudoku/crypto/ed25519.go

@@ -0,0 +1,116 @@
+package crypto
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"errors"
+	"fmt"
+
+	"filippo.io/edwards25519"
+)
+
+// KeyPair holds the scalar private key and point public key
+type KeyPair struct {
+	Private *edwards25519.Scalar
+	Public  *edwards25519.Point
+}
+
+// GenerateMasterKey generates a random master private key (scalar) and its public key (point)
+func GenerateMasterKey() (*KeyPair, error) {
+	// 1. Generate random scalar x (32 bytes)
+	var seed [64]byte
+	if _, err := rand.Read(seed[:]); err != nil {
+		return nil, err
+	}
+
+	x, err := edwards25519.NewScalar().SetUniformBytes(seed[:])
+	if err != nil {
+		return nil, err
+	}
+
+	// 2. Calculate Public Key P = x * G
+	P := new(edwards25519.Point).ScalarBaseMult(x)
+
+	return &KeyPair{Private: x, Public: P}, nil
+}
+
+// SplitPrivateKey takes a master private key x and returns a new random split key (r, k)
+// such that x = r + k (mod L).
+// Returns hex encoded string of r || k (64 bytes)
+func SplitPrivateKey(x *edwards25519.Scalar) (string, error) {
+	// 1. Generate random r (32 bytes)
+	var seed [64]byte
+	if _, err := rand.Read(seed[:]); err != nil {
+		return "", err
+	}
+	r, err := edwards25519.NewScalar().SetUniformBytes(seed[:])
+	if err != nil {
+		return "", err
+	}
+
+	// 2. Calculate k = x - r (mod L)
+	k := new(edwards25519.Scalar).Subtract(x, r)
+
+	// 3. Encode r and k
+	rBytes := r.Bytes()
+	kBytes := k.Bytes()
+
+	full := make([]byte, 64)
+	copy(full[:32], rBytes)
+	copy(full[32:], kBytes)
+
+	return hex.EncodeToString(full), nil
+}
+
+// RecoverPublicKey takes a split private key (r, k) or a master private key (x)
+// and returns the public key P.
+// Input can be:
+// - 32 bytes hex (Master Scalar x)
+// - 64 bytes hex (Split Key r || k)
+func RecoverPublicKey(keyHex string) (*edwards25519.Point, error) {
+	keyBytes, err := hex.DecodeString(keyHex)
+	if err != nil {
+		return nil, fmt.Errorf("invalid hex: %w", err)
+	}
+
+	if len(keyBytes) == 32 {
+		// Master Key x
+		x, err := edwards25519.NewScalar().SetCanonicalBytes(keyBytes)
+		if err != nil {
+			return nil, fmt.Errorf("invalid scalar: %w", err)
+		}
+		return new(edwards25519.Point).ScalarBaseMult(x), nil
+	}
+	if len(keyBytes) == 64 {
+		// Split Key r || k
+		rBytes := keyBytes[:32]
+		kBytes := keyBytes[32:]
+
+		r, err := edwards25519.NewScalar().SetCanonicalBytes(rBytes)
+		if err != nil {
+			return nil, fmt.Errorf("invalid scalar r: %w", err)
+		}
+		k, err := edwards25519.NewScalar().SetCanonicalBytes(kBytes)
+		if err != nil {
+			return nil, fmt.Errorf("invalid scalar k: %w", err)
+		}
+
+		// sum = r + k
+		sum := new(edwards25519.Scalar).Add(r, k)
+
+		// P = sum * G
+		return new(edwards25519.Point).ScalarBaseMult(sum), nil
+	}
+
+	return nil, errors.New("invalid key length: must be 32 bytes (Master) or 64 bytes (Split)")
+}
+
+// EncodePoint returns the hex string of the compressed point
+func EncodePoint(p *edwards25519.Point) string {
+	return hex.EncodeToString(p.Bytes())
+}
+
+// EncodeScalar returns the hex string of the scalar
+func EncodeScalar(s *edwards25519.Scalar) string {
+	return hex.EncodeToString(s.Bytes())
+}