client: started work on API for client, wip

- auction defines description of an auction
- client creates auction object, given a description
- commitment/* merged into client

7 files changed, 205 insertions, 94 deletions

diff --git a/auction.go b/auction.go
new file mode 100644
index 0000000..50d6a2b
--- /dev/null
+++ b/auction.go
@@ -0,0 +1,44 @@
+package seal
+
+import (
+	"crypto"
+	"net/url"
+	"time"
+)
+
+type Type int
+
+const (
+	TypHighest = iota
+	TypSecondHighest
+)
+
+// Auction describes the asset of an auction and other
+// relevant meta-data
+type Description struct {
+	DashboardUrl    *url.URL // can be empty
+	Start           time.Time
+	End             time.Time
+	RoundTimeout    time.Duration // Timeout per round by which all responses must have arrived
+	BitLength       uint8         // Length of the price encoding
+	Currency        string
+	Type            Type
+	SellerPublicKey crypto.PublicKey // Public key of the Seller
+}
+
+// The SignedAuction contains an Auction and the signature,
+// signed by the seller's public key off the SHA512 hash of
+// the normalized JSON-object.
+// TODO(oec): normalized?
+type SignedDesciption struct {
+	Description
+	SellerSignature string
+}
+
+// Bidder is the interface that the Auction engine uses to communicate
+// with an bidder implementation
+type Bidder interface {
+	Result()
+	Broadcast()
+	Unicast()
+}
diff --git a/client/bid.go b/client/bid.go
new file mode 100644
index 0000000..3651d1d
--- /dev/null
+++ b/client/bid.go
@@ -0,0 +1,62 @@
+package client
+
+import (
+	"crypto/ed25519"
+	"fmt"
+
+	. "kesim.org/seal/nizk"
+
+	"kesim.org/seal/nizk/commit"
+)
+
+type bid struct {
+	id ed25519.PrivateKey
+	ID ed25519.PublicKey
+
+	price uint64 // bigendian encoding of the bid
+	n     uint8  // number of bits encoded in zbid.
+
+	// bits are derived from zbid and the zero element in
+	// the slice corresponds to the highest bit in zbid
+	bits []*commit.Statement
+}
+
+// NewBid creates a new Bidder for the given price, using the lower bits up to bitlength
+func newBid(price uint64, bitlength uint8) (*bid, error) {
+	if bitlength > 63 {
+		return nil, fmt.Errorf("bitlength too large, maximum is 63")
+	} else if 0 != (price >> bitlength) {
+		return nil, fmt.Errorf("price %d too large for given bitlength %d", price, bitlength)
+	}
+
+	var (
+		e   error
+		bid = &bid{
+			price: price,
+		}
+	)
+
+	bid.ID, bid.id, e = ed25519.GenerateKey(nil)
+	if e != nil {
+		return nil, e
+	}
+
+	bid.bits = make([]*commit.Statement, bitlength)
+	for i := bitlength; i > 0; i-- {
+		set := (price>>(i-1)&1 != 0)
+		a, b := Curve.RandomScalar(), Curve.RandomScalar()
+		bid.bits[i-1] = commit.NewStatement(a, b, set)
+	}
+
+	return bid, nil
+}
+
+// Commit returns the public commitment to the bits and a signature
+// TODO: return signature over bid
+func (bid *bid) Commit() (c []*commit.Commitment, pub ed25519.PublicKey, sig []byte) {
+	c = make([]*commit.Commitment, len(bid.bits))
+	for i := range bid.bits {
+		c[i] = bid.bits[i].Commit()
+	}
+	return c, bid.ID, nil
+}
\ No newline at end of file
diff --git a/client/bid_test.go b/client/bid_test.go
new file mode 100644
index 0000000..52c4c3c
--- /dev/null
+++ b/client/bid_test.go
@@ -0,0 +1,27 @@
+package client
+
+import (
+	"testing"
+)
+
+func TestBitlengthTooLarge(t *testing.T) {
+	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)
+	if e == nil {
+		t.Fatalf("failure expected, but got bid: %#v", bid)
+	}
+}
+
+func TestBidOK(t *testing.T) {
+	bid, e := newBid(102400, 24)
+	if e != nil {
+		t.Fatalf("unexpected error: %v", e)
+	}
+	t.Logf("Bid: %+v", bid)
+}
\ No newline at end of file
diff --git a/client/client.go b/client/client.go
new file mode 100644
index 0000000..19f0d35
--- /dev/null
+++ b/client/client.go
@@ -0,0 +1,54 @@
+package client
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"kesim.org/seal"
+)
+
+type Auction struct {
+	description *seal.Description
+
+	bid *bid
+
+	log     func(string, ...any)
+	verbose func(string, ...any)
+	debug   func(string, ...any)
+}
+
+func nullf(string, ...any) {}
+
+func NewAuction(description *seal.Description, options ...Option) (auction *Auction, e error) {
+	if description.BitLength > 63 {
+		return nil, fmt.Errorf("Invalid BitLength in description: %d", description.BitLength)
+	}
+
+	logger := log.New(os.Stdout, "[seal::client] ", log.LstdFlags)
+
+	auction = &Auction{
+		description: description,
+		log:         logger.Printf,
+		verbose:     nullf,
+		debug:       nullf,
+	}
+
+	for _, opt := range options {
+		opt(auction)
+	}
+
+	return auction, nil
+}
+
+func (a *Auction) Join(price uint64) error {
+	bid, e := newBid(price, a.description.BitLength)
+	if e != nil {
+		return e
+	}
+
+	a.debug("created bid: %#v\n", bid)
+
+	a.bid = bid
+	return nil
+}
diff --git a/client/option.go b/client/option.go
new file mode 100644
index 0000000..c2b1e5d
--- /dev/null
+++ b/client/option.go
@@ -0,0 +1,18 @@
+package client
+
+import (
+	"log"
+	"os"
+)
+
+type Option func(auction *Auction)
+
+func OptVerbose(a *Auction) {
+	logger := log.New(os.Stdout, "[seal::client][verbose] ", log.LstdFlags)
+	a.verbose = logger.Printf
+}
+
+func OptDebug(a *Auction) {
+	logger := log.New(os.Stdout, "[seal::client][debug] ", log.LstdFlags)
+	a.debug = logger.Printf
+}
diff --git a/commitment/commitment.go b/commitment/commitment.go
deleted file mode 100644
index c958987..0000000
--- a/commitment/commitment.go
+++ /dev/null
@@ -1,59 +0,0 @@
-// Implements the data structures and methods for
-// creating a commitment for the SEAL protocol
-package commitment
-
-import (
-	"fmt"
-
-	"kesim.org/seal/curve"
-)
-
-type Scalar = curve.Curve25519Scalar
-type Point = curve.Curve25519Point
-
-var Curve = curve.Curve25519
-
-type Bidder struct {
-	private struct {
-		id *Scalar
-	}
-	Id *Point
-}
-
-type Bid struct {
-	Bidder *Point
-	zbid   uint64 // bigendian encoding of the bid
-	n      uint8  // number of bits encoded in zbid.
-	bits   []Bit  // derived from zbid
-}
-
-type Bit struct {
-	set bool
-	a   *Scalar
-	b   *Scalar
-	com *BitCommitment
-}
-
-type BitCommitment struct {
-	Gab *Point
-	A   *Point
-	B   *Point
-
-	Proofs struct {
-		A *Proof
-		B *Proof
-	}
-}
-
-type Proof struct {
-	V *Point  `json:"V"`
-	R *Scalar `json:"r"`
-}
-
-func NewBid(price uint64, bitlength uint8) (*Bidder, error) {
-	if bitlength > 63 {
-		return nil, fmt.Errorf("bitlength too large, maximum is 63")
-	}
-
-	return nil, fmt.Errorf("NewBid not implemented")
-}
\ No newline at end of file
diff --git a/main.go b/main.go
deleted file mode 100644
index 4d497a8..0000000
--- a/main.go
+++ /dev/null
@@ -1,35 +0,0 @@
-package seal
-
-import (
-	"crypto"
-	"time"
-)
-
-// Auction describes the asset of an auction and other
-// relevant meta-data
-type Auction struct {
-	// Start date
-	Start time.Time
-	// End date
-	End time.Time
-	// Timeout per round by which all responses must have arrived
-	RoundTimeout time.Duration
-
-	// Sha512 Hash of the Asset
-	AssetHash string
-
-	// Public key of the Seller
-	SellerPublicKey crypto.PublicKey
-}
-
-// The SignedAuction contains an Auction and the signature,
-// signed by the seller's public key off the SHA512 hash of
-// the normalized JSON-object.  TODO(oec): normalized?
-type SignedAuction struct {
-	Auction
-	SellerSignature string
-}
-
-// The published commiment of a participant
-type Commitment struct {
-}