diff --git a/core/interfaces.go b/core/interfaces.go
index 84db750..5be4bc5 100644
--- a/core/interfaces.go
+++ b/core/interfaces.go
@@ -5,24 +5,13 @@ import (
 )
 
 type EntryStore interface {
-	Append(ctx context.Context, entry Entry) error
-	Get(ctx context.Context, entryID EntryID) (Entry, error)
-	GetBySeq(ctx context.Context, ledgerID LedgerID, seq uint64) (Entry, error)
-	Delete(ctx context.Context, entryID EntryID) error
-
-	Head(ctx context.Context, ledgerID LedgerID) (EntryID, error)
-	HeadSeq(context.Context, LedgerID) (uint64, error)
-	Tail(ctx context.Context, ledgerID LedgerID) (EntryID, error)
-	Iterator(ctx context.Context, ledgerLedgerID, startSeq uint64) (EntryIterator, error)
+	Put(ctx context.Context, id EntryID, canonical []byte) error
+	Get(ctx context.Context, id EntryID) ([]byte, error)
+	Has(ctx context.Context, id EntryID) (bool, error)
 }
 
-type EntryIterator interface {
-	Next() bool
-	Entry() Entry
-}
-
-type PayloadStore interface {
-	Put(ctx context.Context, payload []byte) (PayloadID, error)
-	Get(ctx context.Context, payloadID PayloadID) ([]byte, error)
-	Delete(ctx context.Context, payloadID PayloadID) error
+type ReferenceStore interface {
+	GetRef(ctx context.Context, name string) (EntryID, bool, error)
+	SetRef(ctx context.Context, name string, entryID EntryID) (bool, error)
+	RemoveRef(ctx context.Context, name string) error
 }
diff --git a/core/ledger.go b/core/ledger.go
index 72891fe..73b26cb 100644
--- a/core/ledger.go
+++ b/core/ledger.go
@@ -1,107 +1,14 @@
 package core
 
-import (
-	"context"
-	"time"
-
-	"github.com/google/uuid"
-	"lukechampine.com/blake3"
-)
+import ()
 
 type Ledger struct {
-	LedgerID LedgerID
-
-	entryStore   EntryStore
-	payloadStore PayloadStore
-
-	hashChaining bool
+	entryStore     EntryStore
+	referenceStore ReferenceStore
 }
 
-func NewLedger(entryStore EntryStore, payloadStore PayloadStore) (*Ledger, error) {
-	id, err := uuid.NewV7()
-	if err != nil {
-		return nil, err
-	}
-
-	idByes, err := id.MarshalBinary()
-	if err != nil {
-		return nil, err
-	}
-
+func NewLedger(entryStore EntryStore) (*Ledger, error) {
 	return &Ledger{
-		LedgerID:     LedgerID(idByes),
-		entryStore:   entryStore,
-		payloadStore: payloadStore,
+		entryStore: entryStore,
 	}, nil
 }
-
-func (l *Ledger) ID() LedgerID {
-	return l.LedgerID
-}
-
-func (l *Ledger) Head() (Entry, error) {
-	panic("unimplemented")
-}
-
-func (l *Ledger) Append(ctx context.Context, payload []byte) (EntryID, error) {
-	payloadDigest := blake3.Sum256(payload)
-	payloadID, err := l.payloadStore.Put(ctx, payload)
-	if err != nil {
-		return EntryID{}, err
-	}
-
-	entryID, err := uuid.NewV7()
-	entryIDBytes, err := entryID.MarshalBinary()
-	if err != nil {
-		return EntryID{}, err
-	}
-
-	head, err := l.Head()
-	if err != nil {
-		return EntryID{}, err
-	}
-
-	entry := Entry{
-		EntryID:       EntryID(entryIDBytes),
-		LedgerID:      l.LedgerID,
-		Seq:           head.Seq + 1,
-		Timestamp:     time.Now(),
-		PayloadID:     payloadID,
-		PayloadDigest: payloadDigest,
-	}
-
-	entryHash := HashEntry(entry)
-	entry.EntryHash = entryHash
-
-	err = l.entryStore.Append(ctx, entry)
-	if err != nil {
-		return EntryID{}, err
-	}
-
-	return EntryID(entryIDBytes), nil
-}
-
-func (l *Ledger) Get(ctx context.Context, seq uint64) (Entry, []byte, error) {
-	entry, err := l.entryStore.GetBySeq(ctx, l.LedgerID, seq)
-	if err != nil {
-		return Entry{}, nil, err
-	}
-	payload, err := l.payloadStore.Get(ctx, entry.PayloadID)
-	if err != nil {
-		return Entry{}, nil, err
-	}
-
-	return entry, payload, nil
-}
-
-func (l *Ledger) GetEntry(ctx context.Context, seq uint64) (Entry, error) {
-	panic("unimplemented")
-}
-
-func (l *Ledger) GetPayload(ctx context.Context, seq uint64) ([]byte, error) {
-	panic("unimplemented")
-}
-
-func (l *Ledger) Iter(ctx context.Context, startSeq uint64) (EntryIterator, error) {
-	panic("unimplemented")
-}
diff --git a/core/types.go b/core/types.go
index 030b7a0..4d9af37 100644
--- a/core/types.go
+++ b/core/types.go
@@ -1,51 +1,16 @@
 package core
 
 import (
-	"encoding/binary"
 	"time"
-
-	"lukechampine.com/blake3"
 )
 
-type LedgerID [16]byte
-type EntryID [16]byte
-type PayloadID [16]byte
-
-type Hash32 [32]byte
+type EntryID [32]byte
 
 type Entry struct {
 	EntryID EntryID
 
-	LedgerID LedgerID
-	Seq      uint64
+	Previous []EntryID
 
 	Timestamp time.Time
-
-	PayloadID     PayloadID
-	PayloadDigest Hash32
-
-	PreviousHash Hash32
-	EntryHash    Hash32
-}
-
-func HashEntry(e Entry) Hash32 {
-	b := make([]byte, 0, 128)
-
-	b = append(b, "chron.entry.v1"...)
-	b = append(b, e.LedgerID[:]...)
-
-	var buf [8]byte
-	binary.LittleEndian.PutUint64(buf[:], e.Seq)
-	b = append(b, buf[:]...)
-
-	binary.LittleEndian.PutUint64(buf[:], uint64(e.Timestamp.UTC().UnixNano()))
-	b = append(b, buf[:]...)
-
-	b = append(b, e.EntryID[:]...)
-	b = append(b, e.PayloadID[:]...)
-	b = append(b, e.PayloadDigest[:]...)
-	b = append(b, e.PreviousHash[:]...)
-
-	sum := blake3.Sum256(b)
-	return Hash32(sum)
+	Payload   []byte
 }