diff --git a/api/api_storage.go b/api/api_storage.go
index 81f3a33a0..3d2f17ba8 100644
--- a/api/api_storage.go
+++ b/api/api_storage.go
@@ -127,8 +127,8 @@ type SectorInfo struct {
 	CommR    []byte
 	Proof    []byte
 	Deals    []abi.DealID
-	Ticket   sectorbuilder.SealTicket
-	Seed     sectorbuilder.SealSeed
+	Ticket   abi.SealRandomness
+	Seed     abi.Randomness
 	Retries  uint64
 
 	LastErr string
diff --git a/chain/gen/genesis/miners.go b/chain/gen/genesis/miners.go
index 277b77523..6835b778a 100644
--- a/chain/gen/genesis/miners.go
+++ b/chain/gen/genesis/miners.go
@@ -7,7 +7,6 @@ import (
 	"math/rand"
 
 	cborutil "github.com/filecoin-project/go-cbor-util"
-	commcid "github.com/filecoin-project/go-fil-commcid"
 	"github.com/filecoin-project/specs-actors/actors/builtin/power"
 	cbor "github.com/ipfs/go-ipld-cbor"
 
@@ -202,7 +201,7 @@ func SetupStorageMiners(ctx context.Context, cs *store.ChainStore, sroot cid.Cid
 				newSectorInfo := &miner.SectorOnChainInfo{
 					Info: miner.SectorPreCommitInfo{
 						SectorNumber:  preseal.SectorID,
-						SealedCID:     commcid.ReplicaCommitmentV1ToCID(preseal.CommR[:]),
+						SealedCID:     preseal.CommR,
 						SealRandEpoch: 0,
 						DealIDs:       []abi.DealID{dealIDs[pi]},
 						Expiration:    preseal.Deal.EndEpoch,
diff --git a/chain/stmgr/utils.go b/chain/stmgr/utils.go
index 2f99cd9f1..743a30706 100644
--- a/chain/stmgr/utils.go
+++ b/chain/stmgr/utils.go
@@ -2,6 +2,7 @@ package stmgr
 
 import (
 	"context"
+
 	"github.com/filecoin-project/lotus/chain/state"
 
 	amt "github.com/filecoin-project/go-amt-ipld/v2"
@@ -16,10 +17,6 @@ import (
 
 	"github.com/filecoin-project/lotus/chain/actors/aerrors"
 
-	sectorbuilder "github.com/filecoin-project/go-sectorbuilder"
-
-	ffi "github.com/filecoin-project/filecoin-ffi"
-
 	"github.com/filecoin-project/go-address"
 
 	"github.com/filecoin-project/lotus/api"
@@ -155,13 +152,13 @@ func GetMinerSectorSet(ctx context.Context, sm *StateManager, ts *types.TipSet,
 	return LoadSectorsFromSet(ctx, sm.ChainStore().Blockstore(), mas.Sectors)
 }
 
-func GetSectorsForElectionPost(ctx context.Context, sm *StateManager, ts *types.TipSet, maddr address.Address) (*sectorbuilder.SortedPublicSectorInfo, error) {
+func GetSectorsForElectionPost(ctx context.Context, sm *StateManager, ts *types.TipSet, maddr address.Address) ([]abi.SectorInfo, error) {
 	sectors, err := GetMinerProvingSet(ctx, sm, ts, maddr)
 	if err != nil {
 		return nil, xerrors.Errorf("failed to get sector set for miner: %w", err)
 	}
 
-	var uselessOtherArray []ffi.PublicSectorInfo
+	var uselessOtherArray []abi.SectorInfo
 	for _, s := range sectors {
 		cr, err := commcid.CIDToReplicaCommitmentV1(s.Info.Info.SealedCID)
 		if err != nil {
@@ -169,14 +166,14 @@ func GetSectorsForElectionPost(ctx context.Context, sm *StateManager, ts *types.
 		}
 		var uselessBuffer [32]byte
 		copy(uselessBuffer[:], cr)
-		uselessOtherArray = append(uselessOtherArray, ffi.PublicSectorInfo{
-			SectorNum: s.ID,
-			CommR:     uselessBuffer,
+		uselessOtherArray = append(uselessOtherArray, abi.SectorInfo{
+			RegisteredProof: s.Info.Info.RegisteredProof,
+			SectorNumber:    s.ID,
+			SealedCID:       s.Info.Info.SealedCID,
 		})
 	}
 
-	ssi := sectorbuilder.NewSortedPublicSectorInfo(uselessOtherArray)
-	return &ssi, nil
+	return uselessOtherArray, nil
 }
 
 func GetMinerSectorSize(ctx context.Context, sm *StateManager, ts *types.TipSet, maddr address.Address) (abi.SectorSize, error) {
diff --git a/chain/validation/applier.go b/chain/validation/applier.go
index 38f48d6cd..744dbb74b 100644
--- a/chain/validation/applier.go
+++ b/chain/validation/applier.go
@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/filecoin-project/specs-actors/actors/abi"
+	"github.com/filecoin-project/specs-actors/actors/crypto"
 
 	"github.com/filecoin-project/go-sectorbuilder"
 
@@ -64,6 +65,6 @@ type vmRand struct {
 	eCtx *vchain.ExecutionContext
 }
 
-func (*vmRand) GetRandomness(ctx context.Context, h int64) ([]byte, error) {
+func (*vmRand) GetRandomness(ctx context.Context, dst crypto.DomainSeparationTag, h int64, input []byte) ([]byte, error) {
 	panic("implement me")
 }
diff --git a/chain/vm/syscalls.go b/chain/vm/syscalls.go
index 57db24755..63292b348 100644
--- a/chain/vm/syscalls.go
+++ b/chain/vm/syscalls.go
@@ -6,7 +6,6 @@ import (
 	"math/bits"
 
 	"github.com/filecoin-project/go-address"
-	commcid "github.com/filecoin-project/go-fil-commcid"
 	"github.com/filecoin-project/go-sectorbuilder"
 	"github.com/filecoin-project/lotus/lib/zerocomm"
 	"github.com/filecoin-project/specs-actors/actors/abi"
@@ -31,12 +30,17 @@ type syscallShim struct {
 	verifier sectorbuilder.Verifier
 }
 
-func (ss *syscallShim) ComputeUnsealedSectorCID(ssize abi.SectorSize, pieces []abi.PieceInfo) (cid.Cid, error) {
+func (ss *syscallShim) ComputeUnsealedSectorCID(st abi.RegisteredProof, pieces []abi.PieceInfo) (cid.Cid, error) {
 	var sum abi.PaddedPieceSize
 	for _, p := range pieces {
 		sum += p.Size
 	}
 
+	ssize, err := st.SectorSize()
+	if err != nil {
+		return cid.Undef, err
+	}
+
 	{
 		// pad remaining space with 0 CommPs
 		toFill := uint64(abi.PaddedPieceSize(ssize) - sum)
@@ -54,13 +58,13 @@ func (ss *syscallShim) ComputeUnsealedSectorCID(ssize abi.SectorSize, pieces []a
 		}
 	}
 
-	commd, err := sectorbuilder.GenerateDataCommitment(ssize, ffipieces)
+	commd, err := sectorbuilder.GenerateUnsealedCID(st, pieces)
 	if err != nil {
 		log.Errorf("generate data commitment failed: %s", err)
 		return cid.Undef, err
 	}
 
-	return commcid.DataCommitmentV1ToCID(commd[:]), nil
+	return commd, nil
 }
 
 func (ss *syscallShim) HashBlake2b(data []byte) [32]byte {
@@ -106,17 +110,17 @@ func (ss *syscallShim) VerifySeal(info abi.SealVerifyInfo) error {
 
 	miner, err := address.NewIDAddress(uint64(info.Miner))
 	if err != nil {
-		return false, xerrors.Errorf("weirdly failed to construct address: %w", err)
+		return xerrors.Errorf("weirdly failed to construct address: %w", err)
 	}
 
 	ticket := []byte(info.Randomness)
 	proof := []byte(info.OnChain.Proof)
 	seed := []byte(info.InteractiveRandomness)
 
-	log.Infof("Werif %d r:%x; d:%x; m:%s; t:%x; s:%x; N:%d; p:%x", ssize, commR, commD, miner, ticket, seed, info.SectorID.Number, proof)
+	log.Infof("Verif r:%x; d:%x; m:%s; t:%x; s:%x; N:%d; p:%x", commR, commD, miner, ticket, seed, info.SectorID.Number, proof)
 
 	//func(ctx context.Context, maddr address.Address, ssize abi.SectorSize, commD, commR, ticket, proof, seed []byte, sectorID abi.SectorNumber)
-	ok, err := ss.verifier.VerifySeal(ssize, commR[:], commD[:], miner, ticket, seed, info.SectorID.Number, proof)
+	ok, err := ss.verifier.VerifySeal(info)
 	if err != nil {
 		return xerrors.Errorf("failed to validate PoRep: %w", err)
 	}
diff --git a/cmd/lotus-seed/main.go b/cmd/lotus-seed/main.go
index ded25ebf9..46445f1f0 100644
--- a/cmd/lotus-seed/main.go
+++ b/cmd/lotus-seed/main.go
@@ -119,7 +119,12 @@ var preSealCmd = &cli.Command{
 			}
 		}
 
-		gm, key, err := seed.PreSeal(maddr, abi.SectorSize(c.Uint64("sector-size")), abi.SectorNumber(c.Uint64("sector-offset")), c.Int("num-sectors"), sbroot, []byte(c.String("ticket-preimage")), k)
+		rp, err := registeredProofFromSsize(c.Uint64("sector-size"))
+		if err != nil {
+			return err
+		}
+
+		gm, key, err := seed.PreSeal(maddr, rp, abi.SectorNumber(c.Uint64("sector-offset")), c.Int("num-sectors"), sbroot, []byte(c.String("ticket-preimage")), k)
 		if err != nil {
 			return err
 		}
@@ -216,9 +221,20 @@ var aggregateSectorDirsCmd = &cli.Command{
 
 		ssize := abi.SectorSize(cctx.Uint64("sector-size"))
 
+		rp, err := registeredProofFromSsize(cctx.Uint64("sector-size"))
+		if err != nil {
+			return err
+		}
+
+		sp, err := rp.RegisteredSealProof()
+		if err != nil {
+			return err
+		}
+
 		agsb, err := sectorbuilder.New(&sectorbuilder.Config{
 			Miner:         maddr,
-			SectorSize:    ssize,
+			SealProofType: sp,
+			PoStProofType: rp,
 			Paths:         sectorbuilder.SimplePath(destdir),
 			WorkerThreads: 2,
 		}, namespace.Wrap(agmds, datastore.NewKey("/sectorbuilder")))
@@ -279,7 +295,8 @@ var aggregateSectorDirsCmd = &cli.Command{
 
 			sb, err := sectorbuilder.New(&sectorbuilder.Config{
 				Miner:         maddr,
-				SectorSize:    genm.SectorSize,
+				SealProofType: sp,
+				PoStProofType: rp,
 				Paths:         sectorbuilder.SimplePath(dir),
 				WorkerThreads: 2,
 			}, namespace.Wrap(mds, datastore.NewKey("/sectorbuilder")))
@@ -319,3 +336,19 @@ func mergeGenMiners(a, b genesis.Miner) genesis.Miner {
 		Sectors:       append(a.Sectors, b.Sectors...),
 	}
 }
+
+func registeredProofFromSsize(ssize uint64) (abi.RegisteredProof, error) {
+	// TODO: this should be provided to us by something lower down...
+	switch ssize {
+	case 2 << 10:
+		return abi.RegisteredProof_StackedDRG2KiBPoSt, nil
+	case 32 << 30:
+		return abi.RegisteredProof_StackedDRG32GiBPoSt, nil
+	case 8 << 20:
+		return abi.RegisteredProof_StackedDRG8MiBPoSt, nil
+	case 512 << 20:
+		return abi.RegisteredProof_StackedDRG512MiBPoSt, nil
+	default:
+		return 0, fmt.Errorf("unsupported sector size: %d", ssize)
+	}
+}
diff --git a/cmd/lotus-seed/seed/seed.go b/cmd/lotus-seed/seed/seed.go
index 247454ac4..270b35e6d 100644
--- a/cmd/lotus-seed/seed/seed.go
+++ b/cmd/lotus-seed/seed/seed.go
@@ -34,10 +34,21 @@ import (
 
 var log = logging.Logger("preseal")
 
-func PreSeal(maddr address.Address, ssize abi.SectorSize, offset abi.SectorNumber, sectors int, sbroot string, preimage []byte, key *types.KeyInfo) (*genesis.Miner, *types.KeyInfo, error) {
+func PreSeal(maddr address.Address, pt abi.RegisteredProof, offset abi.SectorNumber, sectors int, sbroot string, preimage []byte, key *types.KeyInfo) (*genesis.Miner, *types.KeyInfo, error) {
+	ppt, err := pt.RegisteredPoStProof()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	spt, err := pt.RegisteredSealProof()
+	if err != nil {
+		return nil, nil, err
+	}
+
 	cfg := &sectorbuilder.Config{
 		Miner:           maddr,
-		SectorSize:      ssize,
+		SealProofType:   spt,
+		PoStProofType:   ppt,
 		FallbackLastNum: offset,
 		Paths:           sectorbuilder.SimplePath(sbroot),
 		WorkerThreads:   2,
@@ -57,6 +68,11 @@ func PreSeal(maddr address.Address, ssize abi.SectorSize, offset abi.SectorNumbe
 		return nil, nil, err
 	}
 
+	ssize, err := pt.SectorSize()
+	if err != nil {
+		return nil, nil, err
+	}
+
 	var sealedSectors []*genesis.PreSeal
 	for i := 0; i < sectors; i++ {
 		sid, err := sb.AcquireSectorNumber()
@@ -70,13 +86,11 @@ func PreSeal(maddr address.Address, ssize abi.SectorSize, offset abi.SectorNumbe
 		}
 
 		trand := sha256.Sum256(preimage)
-		ticket := sectorbuilder.SealTicket{
-			TicketBytes: trand,
-		}
+		ticket := abi.SealRandomness(trand[:])
 
 		fmt.Printf("sector-id: %d, piece info: %v\n", sid, pi)
 
-		pco, err := sb.SealPreCommit(context.TODO(), sid, ticket, []sectorbuilder.PublicPieceInfo{pi})
+		scid, ucid, err := sb.SealPreCommit(context.TODO(), sid, ticket, []abi.PieceInfo{pi})
 		if err != nil {
 			return nil, nil, xerrors.Errorf("commit: %w", err)
 		}
@@ -85,10 +99,10 @@ func PreSeal(maddr address.Address, ssize abi.SectorSize, offset abi.SectorNumbe
 			return nil, nil, xerrors.Errorf("trim cache: %w", err)
 		}
 
-		log.Warn("PreCommitOutput: ", sid, pco)
+		log.Warn("PreCommitOutput: ", sid, scid, ucid)
 		sealedSectors = append(sealedSectors, &genesis.PreSeal{
-			CommR:    pco.CommR,
-			CommD:    pco.CommD,
+			CommR:    scid,
+			CommD:    ucid,
 			SectorID: sid,
 		})
 	}
@@ -172,10 +186,8 @@ func commDCID(commd []byte) cid.Cid {
 
 func createDeals(m *genesis.Miner, k *wallet.Key, maddr address.Address, ssize abi.SectorSize) error {
 	for _, sector := range m.Sectors {
-		pref := make([]byte, len(sector.CommD))
-		copy(pref, sector.CommD[:])
 		proposal := &market.DealProposal{
-			PieceCID:             commDCID(pref), // just one deal so this == CommP
+			PieceCID:             sector.CommD,
 			PieceSize:            abi.PaddedPieceSize(ssize),
 			Client:               k.Address,
 			Provider:             maddr,
diff --git a/genesis/types.go b/genesis/types.go
index f699a28b0..5d9073c07 100644
--- a/genesis/types.go
+++ b/genesis/types.go
@@ -6,6 +6,7 @@ import (
 	"github.com/filecoin-project/go-address"
 	"github.com/filecoin-project/specs-actors/actors/abi"
 	"github.com/filecoin-project/specs-actors/actors/builtin/market"
+	"github.com/ipfs/go-cid"
 	"github.com/libp2p/go-libp2p-core/peer"
 )
 
@@ -17,8 +18,8 @@ const (
 )
 
 type PreSeal struct {
-	CommR    [32]byte
-	CommD    [32]byte
+	CommR    cid.Cid
+	CommD    cid.Cid
 	SectorID abi.SectorNumber
 	Deal     market.DealProposal
 }
diff --git a/go.mod b/go.mod
index bd935a2e1..15752691b 100644
--- a/go.mod
+++ b/go.mod
@@ -23,7 +23,7 @@ require (
 	github.com/filecoin-project/go-paramfetch v0.0.2-0.20200218225740-47c639bab663
 	github.com/filecoin-project/go-sectorbuilder v0.0.2-0.20200226210935-4739f8749f56
 	github.com/filecoin-project/go-statestore v0.1.0
-	github.com/filecoin-project/specs-actors v0.0.0-20200226222915-a3b194d36c61
+	github.com/filecoin-project/specs-actors v0.0.0-20200226233922-9ed222007d11
 	github.com/gbrlsnchs/jwt/v3 v3.0.0-beta.1
 	github.com/go-ole/go-ole v1.2.4 // indirect
 	github.com/google/uuid v1.1.1
diff --git a/go.sum b/go.sum
index 3d34bcc5a..5472732a7 100644
--- a/go.sum
+++ b/go.sum
@@ -143,6 +143,10 @@ github.com/filecoin-project/specs-actors v0.0.0-20200226204010-2ecdc6712206/go.m
 github.com/filecoin-project/specs-actors v0.0.0-20200226222440-f5d1be727992 h1:T4BLV7JBn+0xxSzWlmMwU4tCGp2QkqcE+xXwNO0ufBo=
 github.com/filecoin-project/specs-actors v0.0.0-20200226222915-a3b194d36c61 h1:W5/1uYhny36b2x6Ce8awB3tF40z0Lmw7qluukRiVaVM=
 github.com/filecoin-project/specs-actors v0.0.0-20200226222915-a3b194d36c61/go.mod h1:0HAWYrvajFHDgRaKbF0rl+IybVLZL5z4gQ8koCMPhoU=
+github.com/filecoin-project/specs-actors v0.0.0-20200226232338-edd04eb6eda5 h1:B1JCug32caW45wn0X0oifwhFdveLRoi0wrVkKlf7hMs=
+github.com/filecoin-project/specs-actors v0.0.0-20200226232338-edd04eb6eda5/go.mod h1:0HAWYrvajFHDgRaKbF0rl+IybVLZL5z4gQ8koCMPhoU=
+github.com/filecoin-project/specs-actors v0.0.0-20200226233922-9ed222007d11 h1:IJJmTpNWYSdPPyMGP7ET3JE04jjZl7AzGiLTDcJOL04=
+github.com/filecoin-project/specs-actors v0.0.0-20200226233922-9ed222007d11/go.mod h1:0HAWYrvajFHDgRaKbF0rl+IybVLZL5z4gQ8koCMPhoU=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/gbrlsnchs/jwt/v3 v3.0.0-beta.1 h1:EzDjxMg43q1tA2c0MV3tNbaontnHLplHyFF6M5KiVP0=
diff --git a/storage/sbmock/preseal.go b/storage/sbmock/preseal.go
index 983044cb6..4de91d17a 100644
--- a/storage/sbmock/preseal.go
+++ b/storage/sbmock/preseal.go
@@ -2,7 +2,6 @@ package sbmock
 
 import (
 	"github.com/filecoin-project/go-address"
-	commcid "github.com/filecoin-project/go-fil-commcid"
 	"github.com/filecoin-project/specs-actors/actors/abi"
 	"github.com/filecoin-project/specs-actors/actors/abi/big"
 	"github.com/filecoin-project/specs-actors/actors/builtin/market"
@@ -11,6 +10,7 @@ import (
 	"github.com/filecoin-project/lotus/chain/types"
 	"github.com/filecoin-project/lotus/chain/wallet"
 	"github.com/filecoin-project/lotus/genesis"
+	"github.com/filecoin-project/lotus/lib/zerocomm"
 )
 
 func PreSeal(ssize abi.SectorSize, maddr address.Address, sectors int) (*genesis.Miner, *types.KeyInfo, error) {
@@ -30,13 +30,12 @@ func PreSeal(ssize abi.SectorSize, maddr address.Address, sectors int) (*genesis
 
 	for i := range genm.Sectors {
 		preseal := &genesis.PreSeal{}
-		sdata := randB(uint64(abi.PaddedPieceSize(ssize).Unpadded()))
 
-		preseal.CommD = commDR(sdata)
-		preseal.CommR = commDR(preseal.CommD[:])
+		preseal.CommD = zerocomm.ForSize(abi.PaddedPieceSize(ssize).Unpadded())
+		preseal.CommR = zerocomm.ForSize(abi.PaddedPieceSize(ssize).Unpadded())
 		preseal.SectorID = abi.SectorNumber(i + 1)
 		preseal.Deal = market.DealProposal{
-			PieceCID:             commcid.PieceCommitmentV1ToCID(preseal.CommD[:]),
+			PieceCID:             preseal.CommD,
 			PieceSize:            abi.PaddedPieceSize(ssize),
 			Client:               maddr,
 			Provider:             maddr,
diff --git a/storage/sbmock/sbmock.go b/storage/sbmock/sbmock.go
index 4346ccff7..e038affd8 100644
--- a/storage/sbmock/sbmock.go
+++ b/storage/sbmock/sbmock.go
@@ -81,15 +81,11 @@ func (sb *SBMock) AddPiece(ctx context.Context, size abi.UnpaddedPieceSize, sect
 		return abi.PieceInfo{}, err
 	}
 
-	// TODO: no idea what i'm doing here, just making a cid
-	c, err := cid.NewPrefixV1(cid.DagCBOR, 0xf104).Sum(b)
-	if err != nil {
-		return abi.PieceInfo{}, err
-	}
+	c := commcid.DataCommitmentV1ToCID(b[:32]) // hax
 
 	ss.pieces = append(ss.pieces, c)
 	return abi.PieceInfo{
-		Size:     abi.PaddedPieceSize(size),
+		Size:     size.Padded(),
 		PieceCID: c,
 	}, nil
 }
@@ -169,7 +165,7 @@ func (sb *SBMock) SealPreCommit(ctx context.Context, sid abi.SectorNumber, ticke
 	pis := make([]abi.PieceInfo, len(ss.pieces))
 	for i, piece := range ss.pieces {
 		pis[i] = abi.PieceInfo{
-			Size:     abi.UnpaddedPieceSize(32).Padded(),
+			Size:     pieces[i].Size,
 			PieceCID: piece,
 		}
 	}
@@ -183,10 +179,10 @@ func (sb *SBMock) SealPreCommit(ctx context.Context, sid abi.SectorNumber, ticke
 	if err != nil {
 		panic(err)
 	}
+
 	commr := make([]byte, 32)
 	for i := range cc {
-		commr[32-i] = cc[i]
-
+		commr[32-(i+1)] = cc[i]
 	}
 
 	commR := commcid.DataCommitmentV1ToCID(commr)
@@ -378,6 +374,7 @@ func (m mockVerif) GenerateDataCommitment(ssize abi.PaddedPieceSize, pieces []ab
 		panic("todo")
 	}
 	if pieces[0].Size != ssize {
+		fmt.Println("wrong sizes? ", pieces[0].Size, ssize)
 		panic("todo")
 	}
 	return pieces[0].PieceCID, nil
diff --git a/storage/sealing/cbor_gen.go b/storage/sealing/cbor_gen.go
index 3cd9b6451..d13847a99 100644
--- a/storage/sealing/cbor_gen.go
+++ b/storage/sealing/cbor_gen.go
@@ -348,16 +348,6 @@ func (t *Piece) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
-	if len(t.CommP) > cbg.ByteArrayMaxLen {
-		return xerrors.Errorf("Byte array in field t.CommP was too long")
-	}
-
-	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajByteString, uint64(len(t.CommP)))); err != nil {
-		return err
-	}
-	if _, err := w.Write(t.CommP); err != nil {
-		return err
-	}
 	return nil
 }
 
@@ -447,10 +437,6 @@ func (t *Piece) UnmarshalCBOR(r io.Reader) error {
 			if maj != cbg.MajByteString {
 				return fmt.Errorf("expected byte array")
 			}
-			t.CommP = make([]byte, extra)
-			if _, err := io.ReadFull(br, t.CommP); err != nil {
-				return err
-			}
 
 		default:
 			return fmt.Errorf("unknown struct field %d: '%s'", i, name)
@@ -553,17 +539,6 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
-	if len(t.CommD) > cbg.ByteArrayMaxLen {
-		return xerrors.Errorf("Byte array in field t.CommD was too long")
-	}
-
-	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajByteString, uint64(len(t.CommD)))); err != nil {
-		return err
-	}
-	if _, err := w.Write(t.CommD); err != nil {
-		return err
-	}
-
 	// t.CommR ([]uint8) (slice)
 	if len("CommR") > cbg.MaxLength {
 		return xerrors.Errorf("Value in field \"CommR\" was too long")
@@ -576,17 +551,6 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
-	if len(t.CommR) > cbg.ByteArrayMaxLen {
-		return xerrors.Errorf("Byte array in field t.CommR was too long")
-	}
-
-	if _, err := w.Write(cbg.CborEncodeMajorType(cbg.MajByteString, uint64(len(t.CommR)))); err != nil {
-		return err
-	}
-	if _, err := w.Write(t.CommR); err != nil {
-		return err
-	}
-
 	// t.Proof ([]uint8) (slice)
 	if len("Proof") > cbg.MaxLength {
 		return xerrors.Errorf("Value in field \"Proof\" was too long")
@@ -622,10 +586,6 @@ func (t *SectorInfo) MarshalCBOR(w io.Writer) error {
 		return err
 	}
 
-	if err := t.Ticket.MarshalCBOR(w); err != nil {
-		return err
-	}
-
 	// t.PreCommitMessage (cid.Cid) (struct)
 	if len("PreCommitMessage") > cbg.MaxLength {
 		return xerrors.Errorf("Value in field \"PreCommitMessage\" was too long")
@@ -875,10 +835,6 @@ func (t *SectorInfo) UnmarshalCBOR(r io.Reader) error {
 			if maj != cbg.MajByteString {
 				return fmt.Errorf("expected byte array")
 			}
-			t.CommD = make([]byte, extra)
-			if _, err := io.ReadFull(br, t.CommD); err != nil {
-				return err
-			}
 			// t.CommR ([]uint8) (slice)
 		case "CommR":
 
@@ -893,10 +849,6 @@ func (t *SectorInfo) UnmarshalCBOR(r io.Reader) error {
 			if maj != cbg.MajByteString {
 				return fmt.Errorf("expected byte array")
 			}
-			t.CommR = make([]byte, extra)
-			if _, err := io.ReadFull(br, t.CommR); err != nil {
-				return err
-			}
 			// t.Proof ([]uint8) (slice)
 		case "Proof":
 
@@ -920,10 +872,6 @@ func (t *SectorInfo) UnmarshalCBOR(r io.Reader) error {
 
 			{
 
-				if err := t.Ticket.UnmarshalCBOR(br); err != nil {
-					return err
-				}
-
 			}
 			// t.PreCommitMessage (cid.Cid) (struct)
 		case "PreCommitMessage":
diff --git a/storage/sealing/checks.go b/storage/sealing/checks.go
index b45966d9f..ff19afcb7 100644
--- a/storage/sealing/checks.go
+++ b/storage/sealing/checks.go
@@ -5,12 +5,10 @@ import (
 	"context"
 
 	"github.com/ipfs/go-cid"
-	"github.com/multiformats/go-multihash"
 	cbg "github.com/whyrusleeping/cbor-gen"
 	"golang.org/x/xerrors"
 
 	"github.com/filecoin-project/go-address"
-	commcid "github.com/filecoin-project/go-fil-commcid"
 	"github.com/filecoin-project/specs-actors/actors/builtin"
 	"github.com/filecoin-project/specs-actors/actors/builtin/market"
 
@@ -45,7 +43,7 @@ func checkPieces(ctx context.Context, si SectorInfo, api sealingApi) error {
 	for i, piece := range si.Pieces {
 		if piece.DealID == nil {
 			exp := zerocomm.ForSize(piece.Size)
-			if string(piece.CommP) != string(exp[:]) {
+			if piece.CommP != exp {
 				return &ErrInvalidPiece{xerrors.Errorf("deal %d piece %d had non-zero CommP %+v", piece.DealID, i, piece.CommP)}
 			}
 			continue
@@ -55,13 +53,8 @@ func checkPieces(ctx context.Context, si SectorInfo, api sealingApi) error {
 			return &ErrApi{xerrors.Errorf("getting deal %d for piece %d: %w", piece.DealID, i, err)}
 		}
 
-		h, err := multihash.Decode(deal.Proposal.PieceCID.Hash())
-		if err != nil {
-			return &ErrInvalidDeals{xerrors.Errorf("decoding piece CID: %w", err)}
-		}
-
-		if string(h.Digest) != string(piece.CommP) {
-			return &ErrInvalidDeals{xerrors.Errorf("piece %d (or %d) of sector %d refers deal %d with wrong CommP: %x != %x", i, len(si.Pieces), si.SectorID, piece.DealID, piece.CommP, h.Digest)}
+		if deal.Proposal.PieceCID != piece.CommP {
+			return &ErrInvalidDeals{xerrors.Errorf("piece %d (or %d) of sector %d refers deal %d with wrong CommP: %x != %x", i, len(si.Pieces), si.SectorID, piece.DealID, piece.CommP, deal.Proposal.PieceCID)}
 		}
 
 		if piece.Size != deal.Proposal.PieceSize.Unpadded() {
@@ -84,14 +77,9 @@ func checkSeal(ctx context.Context, maddr address.Address, si SectorInfo, api se
 		return &ErrApi{xerrors.Errorf("getting chain head: %w", err)}
 	}
 
-	ssize, err := api.StateMinerSectorSize(ctx, maddr, head.Key())
-	if err != nil {
-		return &ErrApi{err}
-	}
-
 	ccparams, err := actors.SerializeParams(&market.ComputeDataCommitmentParams{
 		DealIDs:    si.deals(),
-		SectorSize: ssize,
+		SectorType: si.SectorType,
 	})
 	if err != nil {
 		return xerrors.Errorf("computing params for ComputeDataCommitment: %w", err)
@@ -118,12 +106,8 @@ func checkSeal(ctx context.Context, maddr address.Address, si SectorInfo, api se
 	if err := c.UnmarshalCBOR(bytes.NewReader(r.Return)); err != nil {
 		return err
 	}
-	cd, err := commcid.CIDToDataCommitmentV1(cid.Cid(c))
-	if err != nil {
-		return err
-	}
 
-	if string(cd) != string(si.CommD) {
+	if cid.Cid(c) != *si.CommD {
 		return &ErrBadCommD{xerrors.Errorf("on chain CommD differs from sector: %x != %x", r.Return, si.CommD)}
 	}
 
diff --git a/storage/sealing/fsm_events.go b/storage/sealing/fsm_events.go
index 528da1234..535f3fd86 100644
--- a/storage/sealing/fsm_events.go
+++ b/storage/sealing/fsm_events.go
@@ -66,14 +66,16 @@ type SectorPackingFailed struct{ error }
 func (evt SectorPackingFailed) apply(*SectorInfo) {}
 
 type SectorSealed struct {
-	commR  []byte
-	commD  []byte
+	commR  cid.Cid
+	commD  cid.Cid
 	ticket SealTicket
 }
 
 func (evt SectorSealed) apply(state *SectorInfo) {
-	state.CommD = evt.commD
-	state.CommR = evt.commR
+	commd := evt.commD
+	state.CommD = &commd
+	commr := evt.commR
+	state.CommR = &commr
 	state.Ticket = evt.ticket
 }
 
diff --git a/storage/sealing/garbage.go b/storage/sealing/garbage.go
index 0a7b33324..289ff2c1a 100644
--- a/storage/sealing/garbage.go
+++ b/storage/sealing/garbage.go
@@ -39,8 +39,8 @@ func (m *Sealing) pledgeSector(ctx context.Context, sectorID abi.SectorNumber, e
 		existingPieceSizes = append(existingPieceSizes, size)
 
 		out[i] = Piece{
-			Size:  ppi.Size,
-			CommP: ppi.CommP[:],
+			Size:  ppi.Size.Unpadded(),
+			CommP: ppi.PieceCID,
 		}
 	}
 
diff --git a/storage/sealing/sealing.go b/storage/sealing/sealing.go
index 9851d77a9..2e1e65ceb 100644
--- a/storage/sealing/sealing.go
+++ b/storage/sealing/sealing.go
@@ -28,7 +28,7 @@ const SectorStorePrefix = "/sectors"
 
 var log = logging.Logger("sectors")
 
-type TicketFn func(context.Context) (*sectorbuilder.SealTicket, error)
+type TicketFn func(context.Context) (SealTicket, error)
 
 type sealingApi interface { // TODO: trim down
 	// Call a read only method on actors (no interaction with the chain required)
@@ -125,8 +125,8 @@ func (m *Sealing) SealPiece(ctx context.Context, size abi.UnpaddedPieceSize, r i
 		{
 			DealID: &dealID,
 
-			Size:  ppi.Size,
-			CommP: ppi.CommP[:],
+			Size:  ppi.Size.Unpadded(),
+			CommP: ppi.PieceCID,
 		},
 	})
 }
diff --git a/storage/sealing/states.go b/storage/sealing/states.go
index a23647502..9dae76694 100644
--- a/storage/sealing/states.go
+++ b/storage/sealing/states.go
@@ -2,9 +2,9 @@ package sealing
 
 import (
 	"context"
+
 	"github.com/filecoin-project/specs-actors/actors/crypto"
 
-	commcid "github.com/filecoin-project/go-fil-commcid"
 	"github.com/filecoin-project/go-sectorbuilder/fs"
 	"github.com/filecoin-project/specs-actors/actors/abi"
 	"github.com/filecoin-project/specs-actors/actors/builtin"
@@ -69,18 +69,15 @@ func (m *Sealing) handleUnsealed(ctx statemachine.Context, sector SectorInfo) er
 		return ctx.Send(SectorSealFailed{xerrors.Errorf("getting ticket failed: %w", err)})
 	}
 
-	rspco, err := m.sb.SealPreCommit(ctx.Context(), sector.SectorID, *ticket, sector.pieceInfos())
+	sealed, unsealed, err := m.sb.SealPreCommit(ctx.Context(), sector.SectorID, ticket.TicketBytes, sector.pieceInfos())
 	if err != nil {
 		return ctx.Send(SectorSealFailed{xerrors.Errorf("seal pre commit failed: %w", err)})
 	}
 
 	return ctx.Send(SectorSealed{
-		commD: rspco.CommD[:],
-		commR: rspco.CommR[:],
-		ticket: SealTicket{
-			BlockHeight: abi.ChainEpoch(ticket.BlockHeight),
-			TicketBytes: ticket.TicketBytes[:],
-		},
+		commD:  unsealed,
+		commR:  sealed,
+		ticket: ticket,
 	})
 }
 
@@ -104,7 +101,7 @@ func (m *Sealing) handlePreCommitting(ctx statemachine.Context, sector SectorInf
 		SectorNumber:    sector.SectorID,
 		RegisteredProof: abi.RegisteredProof_StackedDRG32GiBSeal,
 
-		SealedCID:     commcid.ReplicaCommitmentV1ToCID(sector.CommR),
+		SealedCID:     *sector.CommR,
 		SealRandEpoch: sector.Ticket.BlockHeight,
 		DealIDs:       sector.deals(),
 	}
@@ -161,7 +158,7 @@ func (m *Sealing) handleWaitSeed(ctx statemachine.Context, sector SectorInfo) er
 
 		ctx.Send(SectorSeedReady{seed: SealSeed{
 			BlockHeight: randHeight,
-			TicketBytes: rand,
+			TicketBytes: abi.InteractiveSealRandomness(rand),
 		}})
 
 		return nil
@@ -182,7 +179,7 @@ func (m *Sealing) handleCommitting(ctx statemachine.Context, sector SectorInfo)
 
 	log.Infof("KOMIT %d %x(%d); %x(%d); %v; r:%x; d:%x", sector.SectorID, sector.Ticket.TicketBytes, sector.Ticket.BlockHeight, sector.Seed.TicketBytes, sector.Seed.BlockHeight, sector.pieceInfos(), sector.CommR, sector.CommD)
 
-	proof, err := m.sb.SealCommit(ctx.Context(), sector.SectorID, sector.Ticket.SB(), sector.Seed.SB(), sector.pieceInfos(), sector.rspco())
+	proof, err := m.sb.SealCommit(ctx.Context(), sector.SectorID, sector.Ticket.TicketBytes, sector.Seed.TicketBytes, sector.pieceInfos(), *sector.CommR, *sector.CommD)
 	if err != nil {
 		return ctx.Send(SectorComputeProofFailed{xerrors.Errorf("computing seal proof failed: %w", err)})
 	}
diff --git a/storage/sealing/states_failed.go b/storage/sealing/states_failed.go
index aaffe8b43..a7dfe36a9 100644
--- a/storage/sealing/states_failed.go
+++ b/storage/sealing/states_failed.go
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"time"
 
-	commcid "github.com/filecoin-project/go-fil-commcid"
 	"github.com/filecoin-project/specs-actors/actors/builtin/miner"
 	"github.com/filecoin-project/specs-actors/actors/util/adt"
 	"golang.org/x/xerrors"
@@ -96,13 +95,8 @@ func (m *Sealing) handlePreCommitFailed(ctx statemachine.Context, sector SectorI
 			return nil // TODO: SeedWait needs this currently
 		}
 
-		pciR, err := commcid.CIDToReplicaCommitmentV1(pci.Info.SealedCID)
-		if err != nil {
-			return err
-		}
-
-		if string(pciR) != string(sector.CommR) {
-			log.Warn("sector %d is precommitted on chain, with different CommR: %x != %x", sector.SectorID, pciR, sector.CommR)
+		if pci.Info.SealedCID != *sector.CommR {
+			log.Warn("sector %d is precommitted on chain, with different CommR: %x != %x", sector.SectorID, pci.Info.SealedCID, sector.CommR)
 			return nil // TODO: remove when the actor allows re-precommit
 		}
 
diff --git a/storage/sealing/types.go b/storage/sealing/types.go
index e2a2c049d..3c181ef81 100644
--- a/storage/sealing/types.go
+++ b/storage/sealing/types.go
@@ -1,7 +1,6 @@
 package sealing
 
 import (
-	sectorbuilder "github.com/filecoin-project/go-sectorbuilder"
 	"github.com/filecoin-project/lotus/api"
 	"github.com/filecoin-project/specs-actors/actors/abi"
 	"github.com/ipfs/go-cid"
@@ -9,24 +8,12 @@ import (
 
 type SealTicket struct {
 	BlockHeight abi.ChainEpoch
-	TicketBytes []byte
-}
-
-func (t *SealTicket) SB() sectorbuilder.SealTicket {
-	out := sectorbuilder.SealTicket{BlockHeight: uint64(t.BlockHeight)}
-	copy(out.TicketBytes[:], t.TicketBytes)
-	return out
+	TicketBytes abi.SealRandomness
 }
 
 type SealSeed struct {
 	BlockHeight abi.ChainEpoch
-	TicketBytes []byte
-}
-
-func (t *SealSeed) SB() sectorbuilder.SealSeed {
-	out := sectorbuilder.SealSeed{BlockHeight: uint64(t.BlockHeight)}
-	copy(out.TicketBytes[:], t.TicketBytes)
-	return out
+	TicketBytes abi.InteractiveSealRandomness
 }
 
 func (t *SealSeed) Equals(o *SealSeed) bool {
@@ -37,13 +24,7 @@ type Piece struct {
 	DealID *abi.DealID
 
 	Size  abi.UnpaddedPieceSize
-	CommP []byte
-}
-
-func (p *Piece) ppi() (out sectorbuilder.PublicPieceInfo) {
-	out.Size = p.Size
-	copy(out.CommP[:], p.CommP)
-	return out
+	CommP cid.Cid
 }
 
 type Log struct {
@@ -61,13 +42,15 @@ type SectorInfo struct {
 	SectorID abi.SectorNumber
 	Nonce    uint64 // TODO: remove
 
+	SectorType abi.RegisteredProof
+
 	// Packing
 
 	Pieces []Piece
 
 	// PreCommit
-	CommD  []byte
-	CommR  []byte
+	CommD  *cid.Cid
+	CommR  *cid.Cid
 	Proof  []byte
 	Ticket SealTicket
 
@@ -88,10 +71,13 @@ type SectorInfo struct {
 	Log []Log
 }
 
-func (t *SectorInfo) pieceInfos() []sectorbuilder.PublicPieceInfo {
-	out := make([]sectorbuilder.PublicPieceInfo, len(t.Pieces))
+func (t *SectorInfo) pieceInfos() []abi.PieceInfo {
+	out := make([]abi.PieceInfo, len(t.Pieces))
 	for i, piece := range t.Pieces {
-		out[i] = piece.ppi()
+		out[i] = abi.PieceInfo{
+			Size:     piece.Size.Padded(),
+			PieceCID: piece.CommP,
+		}
 	}
 	return out
 }
@@ -114,12 +100,3 @@ func (t *SectorInfo) existingPieces() []abi.UnpaddedPieceSize {
 	}
 	return out
 }
-
-func (t *SectorInfo) rspco() sectorbuilder.RawSealPreCommitOutput {
-	var out sectorbuilder.RawSealPreCommitOutput
-
-	copy(out.CommD[:], t.CommD)
-	copy(out.CommR[:], t.CommR)
-
-	return out
-}
diff --git a/storage/sealing/types_test.go b/storage/sealing/types_test.go
index 75460d3f8..32849e40c 100644
--- a/storage/sealing/types_test.go
+++ b/storage/sealing/types_test.go
@@ -5,14 +5,17 @@ import (
 	"testing"
 
 	"github.com/filecoin-project/specs-actors/actors/abi"
+	"github.com/filecoin-project/specs-actors/actors/builtin"
 	"gotest.tools/assert"
 
-	"github.com/filecoin-project/go-cbor-util"
+	cborutil "github.com/filecoin-project/go-cbor-util"
 )
 
 func TestSectorInfoSelialization(t *testing.T) {
 	d := abi.DealID(1234)
 
+	dummyCid := builtin.AccountActorCodeID
+
 	si := &SectorInfo{
 		State:    123,
 		SectorID: 234,
@@ -20,9 +23,9 @@ func TestSectorInfoSelialization(t *testing.T) {
 		Pieces: []Piece{{
 			DealID: &d,
 			Size:   5,
-			CommP:  []byte{3},
+			CommP:  dummyCid,
 		}},
-		CommD: []byte{32, 4},
+		CommD: &dummyCid,
 		CommR: nil,
 		Proof: nil,
 		Ticket: SealTicket{
diff --git a/storage/sealing/utils_test.go b/storage/sealing/utils_test.go
index a5287fd87..1d6b6c515 100644
--- a/storage/sealing/utils_test.go
+++ b/storage/sealing/utils_test.go
@@ -5,8 +5,6 @@ import (
 
 	"github.com/filecoin-project/specs-actors/actors/abi"
 
-	"github.com/filecoin-project/lotus/storage/sbmock"
-
 	"github.com/stretchr/testify/assert"
 )
 
@@ -45,19 +43,3 @@ func TestFillersFromRem(t *testing.T) {
 		testFill(t, ub, []abi.UnpaddedPieceSize{ub1, ub4})
 	}
 }
-
-func TestFastPledge(t *testing.T) {
-	sz := abi.PaddedPieceSize(16 << 20)
-
-	s := Sealing{sb: sbmock.NewMockSectorBuilder(0, abi.SectorSize(sz))}
-	if _, err := s.fastPledgeCommitment(sz.Unpadded(), 5); err != nil {
-		t.Fatalf("%+v", err)
-	}
-
-	sz = abi.PaddedPieceSize(1024)
-
-	s = Sealing{sb: sbmock.NewMockSectorBuilder(0, abi.SectorSize(sz))}
-	if _, err := s.fastPledgeCommitment(sz.Unpadded(), 64); err != nil {
-		t.Fatalf("%+v", err)
-	}
-}