diff --git a/libs/httpsignature/nitro_test.go b/libs/httpsignature/nitro_test.go
index 566d5d42e..5db151bef 100644
--- a/libs/httpsignature/nitro_test.go
+++ b/libs/httpsignature/nitro_test.go
@@ -30,7 +30,7 @@ func TestVerifyNitroAttestation(t *testing.T) {
 		t.Fatal("error reading sample attestation doc:", err)
 	}
 
-	verifier := NitroVerifier{PCRs: pcrs, now: now}
+	verifier := NitroVerifier{PCRs: pcrs, Now: now}
 
 	valid, err := verifier.Verify([]byte{}, doc, crypto.Hash(0))
 	if err != nil {
diff --git a/libs/nitro/attestation.go b/libs/nitro/attestation.go
index bbfe22fc7..7e4409ffb 100644
--- a/libs/nitro/attestation.go
+++ b/libs/nitro/attestation.go
@@ -113,14 +113,14 @@ func (s Signer) Sign(rand io.Reader, message []byte, opts crypto.SignerOpts) (si
 // Verifier specifies the PCR values required for verification
 type Verifier struct {
 	PCRs map[uint][]byte
-	now  func() time.Time
+	Now  func() time.Time
 }
 
 // NewVerifier returns a new verifier for nitro attestations
 func NewVerifier(pcrs map[uint][]byte) Verifier {
 	return Verifier{
 		PCRs: pcrs,
-		now:  time.Now,
+		Now:  time.Now,
 	}
 }
 
@@ -136,7 +136,7 @@ func (v Verifier) verifySigOnlyNotPCRs(message, sig []byte, opts crypto.SignerOp
 		sig,
 		nitrite.VerifyOptions{
 			Roots:       pool,
-			CurrentTime: v.now(),
+			CurrentTime: v.Now(),
 		},
 	)
 	if nil != err {
diff --git a/libs/payments/crypto.go b/libs/payments/crypto.go
index 424f21ebe..3f0077d7c 100644
--- a/libs/payments/crypto.go
+++ b/libs/payments/crypto.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto"
 	"io"
+	"time"
 )
 
 // Signator is an interface for cryptographic signature creation
@@ -19,6 +20,6 @@ type Verifier interface {
 
 // Keystore provides a way to lookup a public key based on the keyID a request was signed with
 type Keystore interface {
-	// LookupVerifier based on the keyID
-	LookupVerifier(ctx context.Context, keyID string) (context.Context, *Verifier, error)
+	// LookupVerifier based on the keyID and updatedAt
+	LookupVerifier(ctx context.Context, keyID string, updatedAt time.Time) (context.Context, *Verifier, error)
 }
diff --git a/libs/payments/state.go b/libs/payments/state.go
index 68c1c0d01..362af260a 100644
--- a/libs/payments/state.go
+++ b/libs/payments/state.go
@@ -6,6 +6,7 @@ import (
 	"crypto/rand"
 	"encoding/json"
 	"fmt"
+	"time"
 
 	"github.com/google/uuid"
 	"github.com/shopspring/decimal"
@@ -50,6 +51,7 @@ type PaymentState struct {
 	Signature          []byte    `ion:"signature"`
 	PublicKey          string    `ion:"publicKey"`
 	ID                 uuid.UUID `ion:"idempotencyKey"`
+	UpdatedAt          time.Time `ion:"-"`
 }
 
 // PaymentStateHistory is a sequence of payment states.
@@ -133,7 +135,7 @@ func (p PaymentStateHistory) GetAuthenticatedPaymentState(keystore Keystore, doc
 	// 3. the transition was valid
 	var authenticatedState AuthenticatedPaymentState
 	for i, state := range []PaymentState(p) {
-		_, verifier, err := keystore.LookupVerifier(context.Background(), state.PublicKey)
+		_, verifier, err := keystore.LookupVerifier(context.Background(), state.PublicKey, state.UpdatedAt)
 		if err != nil {
 			return nil, fmt.Errorf("signature validation for state with document ID %s failed: %w", documentID, err)
 		}
diff --git a/services/payments/datastore.go b/services/payments/datastore.go
index b274f8039..ae9211a6d 100644
--- a/services/payments/datastore.go
+++ b/services/payments/datastore.go
@@ -123,6 +123,7 @@ func (q *QLDBDatastore) GetPaymentStateHistory(ctx context.Context, documentID s
 			if err != nil {
 				return nil, fmt.Errorf("ion unmarshal failed: %w", err)
 			}
+			latestHistoryItem.Data.UpdatedAt = latestHistoryItem.Metadata.TxTime
 			stateHistory = append(stateHistory, latestHistoryItem.Data)
 		}
 
diff --git a/services/payments/state_verifier.go b/services/payments/state_verifier.go
index 71a04e3d9..812d200f6 100644
--- a/services/payments/state_verifier.go
+++ b/services/payments/state_verifier.go
@@ -5,6 +5,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"time"
 
 	"github.com/brave-intl/bat-go/libs/nitro"
 	"github.com/brave-intl/bat-go/libs/payments"
@@ -14,7 +15,7 @@ import (
 var previousPCR2Values = []string{}
 
 type VerifierStore struct {
-	verifiers map[string]payments.Verifier
+	verifiers map[string]nitro.Verifier
 }
 
 func NewVerifierStore() (*VerifierStore, error) {
@@ -23,7 +24,7 @@ func NewVerifierStore() (*VerifierStore, error) {
 		return nil, errors.New("could not retrieve nitro PCRs")
 	}
 
-	s := VerifierStore{verifiers: map[string]payments.Verifier{}}
+	s := VerifierStore{verifiers: map[string]nitro.Verifier{}}
 
 	// always accept attestations matching our own
 	pubKey := hex.EncodeToString(pcrs[2])
@@ -48,10 +49,12 @@ func NewVerifierStore() (*VerifierStore, error) {
 
 }
 
-func (s *VerifierStore) LookupVerifier(ctx context.Context, keyID string) (context.Context, *payments.Verifier, error) {
+func (s *VerifierStore) LookupVerifier(ctx context.Context, keyID string, updatedAt time.Time) (context.Context, *payments.Verifier, error) {
 	for k, v := range s.verifiers {
 		if k == keyID {
-			return ctx, &v, nil
+			v.Now = func() time.Time { return updatedAt }
+			vv := (payments.Verifier)(v)
+			return ctx, &vv, nil
 		}
 	}
 	return ctx, nil, fmt.Errorf("unknown key: %s", keyID)