diff --git a/WORKSPACE b/WORKSPACE
index dfe700190fc8..105a176f80ca 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -1654,8 +1654,8 @@ go_repository(
     name = "com_github_wealdtech_eth2_signer_api",
     build_file_proto_mode = "disable_global",
     importpath = "github.com/wealdtech/eth2-signer-api",
-    sum = "h1:fqJYjKwG/FeUAJYYiZblIP6agiz3WWB+Hxpw85Fnr5I=",
-    version = "v1.0.1",
+    sum = "h1:Fs0GfrdhboBKW7zaMvIvUHJaOB1ibpAmRG3lkB53in4=",
+    version = "v1.3.0",
 )
 
 go_repository(
diff --git a/validator/client/validator_aggregate.go b/validator/client/validator_aggregate.go
index c90ce75cb395..03109f368fff 100644
--- a/validator/client/validator_aggregate.go
+++ b/validator/client/validator_aggregate.go
@@ -165,11 +165,7 @@ func (v *validator) aggregateAndProofSig(ctx context.Context, pubKey [48]byte, a
 	if err != nil {
 		return nil, err
 	}
-	signedRoot, err := helpers.ComputeSigningRoot(agg, d.SignatureDomain)
-	if err != nil {
-		return nil, err
-	}
-	sig, err := v.keyManager.Sign(pubKey, signedRoot)
+	sig, err := v.signObject(pubKey, agg, d.SignatureDomain)
 	if err != nil {
 		return nil, err
 	}
diff --git a/validator/client/validator_propose.go b/validator/client/validator_propose.go
index 336f7c903ff4..17a988cf63cb 100644
--- a/validator/client/validator_propose.go
+++ b/validator/client/validator_propose.go
@@ -193,10 +193,11 @@ func (v *validator) signBlock(ctx context.Context, pubKey [48]byte, epoch uint64
 			return nil, errors.Wrap(err, "could not get signing root")
 		}
 		blockHeader := &ethpb.BeaconBlockHeader{
-			Slot:       b.Slot,
-			StateRoot:  b.StateRoot,
-			ParentRoot: b.ParentRoot,
-			BodyRoot:   bodyRoot[:],
+			Slot:          b.Slot,
+			ProposerIndex: b.ProposerIndex,
+			StateRoot:     b.StateRoot,
+			ParentRoot:    b.ParentRoot,
+			BodyRoot:      bodyRoot[:],
 		}
 		sig, err = protectingKeymanager.SignProposal(pubKey, bytesutil.ToBytes32(domain.SignatureDomain), blockHeader)
 		if err != nil {
diff --git a/validator/keymanager/BUILD.bazel b/validator/keymanager/BUILD.bazel
index 384ded3119c3..4540021ec454 100644
--- a/validator/keymanager/BUILD.bazel
+++ b/validator/keymanager/BUILD.bazel
@@ -39,6 +39,7 @@ go_test(
         "direct_interop_test.go",
         "direct_test.go",
         "opts_test.go",
+        "remote_internal_test.go",
         "remote_test.go",
         "wallet_test.go",
     ],
diff --git a/validator/keymanager/remote.go b/validator/keymanager/remote.go
index 675a0acbb093..a4b4feb03baa 100644
--- a/validator/keymanager/remote.go
+++ b/validator/keymanager/remote.go
@@ -5,7 +5,10 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
+	"regexp"
+	"strings"
 
 	"github.com/pkg/errors"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
@@ -16,6 +19,11 @@ import (
 	"google.golang.org/grpc/credentials"
 )
 
+const (
+	// maxMessageSize is the largest message that can be received over GRPC.  Set to 8MB, which handles ~128K keys.
+	maxMessageSize = 8 * 1024 * 1024
+)
+
 // Remote is a key manager that accesses a remote wallet daemon.
 type Remote struct {
 	paths               []string
@@ -115,6 +123,8 @@ func NewRemoteWallet(input string) (KeyManager, string, error) {
 	grpcOpts := []grpc.DialOption{
 		// Require TLS with client certificate.
 		grpc.WithTransportCredentials(clientCreds),
+		// Receive large messages without erroring.
+		grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(maxMessageSize)),
 	}
 
 	conn, err := grpc.Dial(opts.Location, grpcOpts...)
@@ -129,7 +139,7 @@ func NewRemoteWallet(input string) (KeyManager, string, error) {
 
 	err = km.RefreshValidatingKeys()
 	if err != nil {
-		return nil, remoteOptsHelp, errors.New("failed to fetch accounts from remote wallet")
+		return nil, remoteOptsHelp, errors.Wrap(err, "failed to fetch accounts from remote wallet")
 	}
 
 	return km, remoteOptsHelp, nil
@@ -167,9 +177,9 @@ func (km *Remote) SignGeneric(pubKey [48]byte, root [32]byte, domain [32]byte) (
 		return nil, err
 	}
 	switch resp.State {
-	case pb.SignState_DENIED:
+	case pb.ResponseState_DENIED:
 		return nil, ErrDenied
-	case pb.SignState_FAILED:
+	case pb.ResponseState_FAILED:
 		return nil, ErrCannotSign
 	}
 	return bls.SignatureFromBytes(resp.Signature)
@@ -187,10 +197,11 @@ func (km *Remote) SignProposal(pubKey [48]byte, domain [32]byte, data *ethpb.Bea
 		Id:     &pb.SignBeaconProposalRequest_Account{Account: accountInfo.Name},
 		Domain: domain[:],
 		Data: &pb.BeaconBlockHeader{
-			Slot:       data.Slot,
-			ParentRoot: data.ParentRoot,
-			StateRoot:  data.StateRoot,
-			BodyRoot:   data.BodyRoot,
+			Slot:          data.Slot,
+			ProposerIndex: data.ProposerIndex,
+			ParentRoot:    data.ParentRoot,
+			StateRoot:     data.StateRoot,
+			BodyRoot:      data.BodyRoot,
 		},
 	}
 	resp, err := client.SignBeaconProposal(context.Background(), req)
@@ -198,9 +209,9 @@ func (km *Remote) SignProposal(pubKey [48]byte, domain [32]byte, data *ethpb.Bea
 		return nil, err
 	}
 	switch resp.State {
-	case pb.SignState_DENIED:
+	case pb.ResponseState_DENIED:
 		return nil, ErrDenied
-	case pb.SignState_FAILED:
+	case pb.ResponseState_FAILED:
 		return nil, ErrCannotSign
 	}
 	return bls.SignatureFromBytes(resp.Signature)
@@ -236,9 +247,9 @@ func (km *Remote) SignAttestation(pubKey [48]byte, domain [32]byte, data *ethpb.
 		return nil, err
 	}
 	switch resp.State {
-	case pb.SignState_DENIED:
+	case pb.ResponseState_DENIED:
 		return nil, ErrDenied
-	case pb.SignState_FAILED:
+	case pb.ResponseState_FAILED:
 		return nil, ErrCannotSign
 	}
 	return bls.SignatureFromBytes(resp.Signature)
@@ -250,12 +261,31 @@ func (km *Remote) RefreshValidatingKeys() error {
 	listAccountsReq := &pb.ListAccountsRequest{
 		Paths: km.paths,
 	}
-	accountsResp, err := listerClient.ListAccounts(context.Background(), listAccountsReq)
+	resp, err := listerClient.ListAccounts(context.Background(), listAccountsReq)
 	if err != nil {
-		panic(err)
+		return err
+	}
+	if resp.State == pb.ResponseState_DENIED {
+		return errors.New("attempt to fetch keys denied")
+	}
+	if resp.State == pb.ResponseState_FAILED {
+		return errors.New("attempt to fetch keys failed")
 	}
-	accounts := make(map[[48]byte]*accountInfo, len(accountsResp.Accounts))
-	for _, account := range accountsResp.Accounts {
+
+	verificationRegexes := pathsToVerificationRegexes(km.paths)
+	accounts := make(map[[48]byte]*accountInfo, len(resp.Accounts))
+	for _, account := range resp.Accounts {
+		verified := false
+		for _, verificationRegex := range verificationRegexes {
+			if verificationRegex.Match([]byte(account.Name)) {
+				verified = true
+				break
+			}
+		}
+		if !verified {
+			log.WithField("path", account.Name).Warn("Received unwanted account from server; ignoring")
+			continue
+		}
 		account := &accountInfo{
 			Name:   account.Name,
 			PubKey: account.PublicKey,
@@ -265,3 +295,35 @@ func (km *Remote) RefreshValidatingKeys() error {
 	km.accounts = accounts
 	return nil
 }
+
+// pathsToVerificationRegexes turns path specifiers in to regexes to ensure accounts we are given are good.
+func pathsToVerificationRegexes(paths []string) []*regexp.Regexp {
+	regexes := make([]*regexp.Regexp, 0, len(paths))
+	for _, path := range paths {
+		log := log.WithField("path", path)
+		parts := strings.Split(path, "/")
+		if len(parts) == 0 || len(parts[0]) == 0 {
+			log.Debug("Invalid path")
+			continue
+		}
+		if len(parts) == 1 {
+			parts = append(parts, ".*")
+		}
+		if strings.HasPrefix(parts[1], "^") {
+			parts[1] = parts[1][1:]
+		}
+		var specifier string
+		if strings.HasSuffix(parts[1], "$") {
+			specifier = fmt.Sprintf("^%s/%s", parts[0], parts[1])
+		} else {
+			specifier = fmt.Sprintf("^%s/%s$", parts[0], parts[1])
+		}
+		regex, err := regexp.Compile(specifier)
+		if err != nil {
+			log.WithField("specifier", specifier).WithError(err).Warn("Invalid path regex")
+			continue
+		}
+		regexes = append(regexes, regex)
+	}
+	return regexes
+}
diff --git a/validator/keymanager/remote_internal_test.go b/validator/keymanager/remote_internal_test.go
new file mode 100644
index 000000000000..9d6a4dc4690e
--- /dev/null
+++ b/validator/keymanager/remote_internal_test.go
@@ -0,0 +1,58 @@
+package keymanager
+
+import (
+	"testing"
+)
+
+func TestPathsToVerificationRegexes(t *testing.T) {
+	tests := []struct {
+		name    string
+		paths   []string
+		regexes []string
+		err     string
+	}{
+		{
+			name:    "Empty",
+			regexes: []string{},
+		},
+		{
+			name:    "IgnoreBadPaths",
+			paths:   []string{"", "/", "/Account"},
+			regexes: []string{},
+		},
+		{
+			name:    "Simple",
+			paths:   []string{"Wallet/Account"},
+			regexes: []string{"^Wallet/Account$"},
+		},
+		{
+			name:    "Multiple",
+			paths:   []string{"Wallet/Account1", "Wallet/Account2"},
+			regexes: []string{"^Wallet/Account1$", "^Wallet/Account2$"},
+		},
+		{
+			name:    "IgnoreInvalidRegex",
+			paths:   []string{"Wallet/Account1", "Bad/***", "Wallet/Account2"},
+			regexes: []string{"^Wallet/Account1$", "^Wallet/Account2$"},
+		},
+		{
+			name:    "TidyExistingAnchors",
+			paths:   []string{"Wallet/^.*$", "Wallet/Foo.*Bar$", "Wallet/^Account"},
+			regexes: []string{"^Wallet/.*$", "^Wallet/Foo.*Bar$", "^Wallet/Account$"},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			regexes := pathsToVerificationRegexes(test.paths)
+			if len(regexes) != len(test.regexes) {
+				t.Fatalf("Unexpected number of regexes: expected %v, received %v", len(test.regexes), len(regexes))
+			}
+			for i := range regexes {
+				if regexes[i].String() != test.regexes[i] {
+					t.Fatalf("Unexpected regex %d: expected %v, received %v", i, test.regexes[i], regexes[i].String())
+				}
+			}
+		})
+	}
+}