diff --git a/protocol/config/consensus.go b/protocol/config/consensus.go
index 87afbc5c..f83621b0 100644
--- a/protocol/config/consensus.go
+++ b/protocol/config/consensus.go
@@ -262,8 +262,9 @@ type ConsensusParams struct {
 	// be read in the transaction
 	MaxAppTxnForeignAssets int
 
-	// maximum number of "foreign references" (accounts, asa, app, boxes)
-	// that can be attached to a single app call.
+	// maximum number of "foreign references" (accounts, asa, app, boxes) that
+	// can be attached to a single app call.  Modern transactions can use
+	// MaxAccess references in txn.Access to access more.
 	MaxAppTotalTxnReferences int
 
 	// maximum cost of application approval program or clear state program
@@ -335,6 +336,9 @@ type ConsensusParams struct {
 	// Number of box references allowed
 	MaxAppBoxReferences int
 
+	// Number of references allowed in txn.Access
+	MaxAppAccess int
+
 	// Amount added to a txgroup's box I/O budget per box ref supplied.
 	// For reads: the sum of the sizes of all boxes in the group must be less than I/O budget
 	// For writes: the sum of the sizes of all boxes created or written must be less than I/O budget
@@ -1289,6 +1293,11 @@ func initConsensusProtocols() {
 	vFuture.EnableAppVersioning = true // if not promoted when v12 goes into effect, update logic/field.go
 	vFuture.EnableSha512BlockHash = true
 
+	// txn.Access work
+	vFuture.MaxAppTxnAccounts = 8       // Accounts are no worse than others, they should be the same
+	vFuture.MaxAppAccess = 16           // Twice as many, though cross products are explicit
+	vFuture.BytesPerBoxReference = 2048 // Count is more important that bytes, loosen up
+
 	Consensus[protocol.ConsensusFuture] = vFuture
 
 	// vAlphaX versions are an separate series of consensus parameters and versions for alphanet
diff --git a/types/applications.go b/types/applications.go
index da3f4b20..b912980e 100644
--- a/types/applications.go
+++ b/types/applications.go
@@ -32,6 +32,35 @@ type BoxReference struct {
 	Name []byte `codec:"n"`
 }
 
+// ResourceRef names a single resource
+type ResourceRef struct {
+	_struct struct{} `codec:",omitempty,omitemptyarray"`
+
+	// Only one of these may be set
+	Address Address      `codec:"d"`
+	Asset   AssetIndex   `codec:"s"`
+	App     AppIndex     `codec:"p"`
+	Holding HoldingRef   `codec:"h"`
+	Locals  LocalsRef    `codec:"l"`
+	Box     BoxReference `codec:"b"`
+}
+
+// HoldingRef names a holding by referring to an Address and Asset that appear
+// earlier in the Access list (0 is special cased)
+type HoldingRef struct {
+	_struct struct{} `codec:",omitempty,omitemptyarray"`
+	Address uint64   `codec:"d"` // 0=Sender,n-1=index into the Access list, which must be an Address
+	Asset   uint64   `codec:"s"` // n-1=index into the Access list, which must be an Asset
+}
+
+// LocalsRef names a local state by referring to an Address and App that appear
+// earlier in the Access list (0 is special cased)
+type LocalsRef struct {
+	_struct struct{} `codec:",omitempty,omitemptyarray"`
+	Address uint64   `codec:"d"` // 0=Sender,n-1=index into the Access list, which must be an Address
+	App     uint64   `codec:"p"` // 0=ApplicationID,n-1=index into the Access list, which must be an App
+}
+
 // OnCompletion is an enum representing some layer 1 side effect that an
 // ApplicationCall transaction will have if it is included in a block.
 //
@@ -93,22 +122,29 @@ type ApplicationCallTxnFields struct {
 	// the app or asset id).
 	Accounts []Address `codec:"apat"`
 
+	// ForeignAssets are asset IDs for assets whose AssetParams
+	// (and since v4, Holdings) may be read by the executing
+	// ApprovalProgram or ClearStateProgram.
+	ForeignAssets []AssetIndex `codec:"apas"`
+
 	// ForeignApps are application IDs for applications besides
 	// this one whose GlobalState (or Local, since v4) may be read
 	// by the executing ApprovalProgram or ClearStateProgram.
 	ForeignApps []AppIndex `codec:"apfa"`
 
+	// Access unifies `Accounts`, `ForeignApps`, `ForeignAssets`, and `Boxes`
+	// under a single list. It removes all implicitly available resources, so
+	// "cross-product" resources (holdings and locals) must be explicitly
+	// listed, as well as app accounts, even the app account of the called app!
+	// Transactions using Access may not use the other lists.
+	Access []ResourceRef `codec:"al"`
+
 	// Boxes are the boxes that can be accessed by this transaction (and others
 	// in the same group). The Index in the BoxRef is the slot of ForeignApps
 	// that the name is associated with (shifted by 1, so 0 indicates "current
-	// app")
+	// app") If Access is used, the indexes refer to it.
 	BoxReferences []BoxReference `codec:"apbx"`
 
-	// ForeignAssets are asset IDs for assets whose AssetParams
-	// (and since v4, Holdings) may be read by the executing
-	// ApprovalProgram or ClearStateProgram.
-	ForeignAssets []AssetIndex `codec:"apas"`
-
 	// LocalStateSchema specifies the maximum number of each type that may
 	// appear in the local key/value store of users who opt in to this
 	// application. This field is only used during application creation