3 files changed, 22 insertions, 7 deletions
diff --git a/bidder/auction.go b/bidder/auction.go
index 5331136..a22f005 100644
--- a/bidder/auction.go
+++ b/bidder/auction.go
@@ -6,12 +6,27 @@ import (
 	"os"
 
 	"kesim.org/seal"
+	"kesim.org/seal/nizk/commit"
 )
 
+// Auction is the simple interface for the engine
+type Auction interface {
+	Join(bidder Bidder)                   // A bidder calls this to join the auction
+	GotMessage(msg []byte, sig []byte) error // A bidder uses this method to publish a message
+}
+
+// Bidder is the interface that the Auction engine uses to communicate
+type Bidder interface {
+	Commitment() *commit.Commitment
+	Start(map[string]*commit.Commitment)
+	Result()
+	Receive(msg []byte) error
+}
+
 type auction struct {
 	description *seal.Description
 
-	bidder seal.Bidder
+	bidder Bidder
 
 	log     func(string, ...any)
 	verbose func(string, ...any)
@@ -41,7 +56,7 @@ func NewAuction(description *seal.Description, options ...Option) (a *auction, e
 	return a, nil
 }
 
-func (a *auction) Join(bidder seal.Bidder) {
+func (a *auction) Join(bidder Bidder) {
 	a.bidder = bidder
 }
 
diff --git a/bidder/bid.go b/bidder/bid.go
index ba93a64..5f98a0c 100644
--- a/bidder/bid.go
+++ b/bidder/bid.go
@@ -31,8 +31,8 @@ type bid struct {
 	stage1 []*stage1.Statement
 }
 
-// NewBid creates a new Bidder for the given price, using the lower bits up to bitlength
-func NewBid(price uint64, bitlength uint8) (b *bid, e error) {
+// newBid creates a new Bidder for the given price, using the lower bits up to bitlength
+func newBid(price uint64, bitlength uint8) (b *bid, e error) {
 	if bitlength > 63 {
 		return nil, fmt.Errorf("bitlength too large, maximum is 63")
 	} else if 0 != (price >> bitlength) {
diff --git a/bidder/bid_test.go b/bidder/bid_test.go
index de6afd9..a479e5d 100644
--- a/bidder/bid_test.go
+++ b/bidder/bid_test.go
@@ -5,21 +5,21 @@ import (
 )
 
 func TestBitlengthTooLarge(t *testing.T) {
-	bid, e := NewBid(0xFFFFFF, 70)
+	bid, e := newBid(0xFFFFFF, 70)
 	if e == nil {
 		t.Fatalf("failure expected, but got bid: %#v", bid)
 	}
 }
 
 func TestPriceTooLarge(t *testing.T) {
-	bid, e := NewBid(0xFFFFFF, 8)
+	bid, e := newBid(0xFFFFFF, 8)
 	if e == nil {
 		t.Fatalf("failure expected, but got bid: %#v", bid)
 	}
 }
 
 func TestBidOK(t *testing.T) {
-	bid, e := NewBid(102400, 24)
+	bid, e := newBid(102400, 24)
 	if e != nil {
 		t.Fatalf("unexpected error: %v", e)
 	}