feat: support issuer key rollover by each key having its own revocation update update

internal/servercore/api.go

@@ -140,18 +140,7 @@ func (s *Server) CancelSession(token string) error {
 }
 
 func (s *Server) Revoke(credid irma.CredentialTypeIdentifier, key string) error {
-	sk, err := s.conf.IrmaConfiguration.PrivateKey(credid.IssuerIdentifier())
-	if err != nil {
-		return err
-	}
-	if sk == nil {
-		return errors.Errorf("cannot revoke: private key of %s not found", credid.IssuerIdentifier())
-	}
-	rsk, err := sk.RevocationKey()
-	if err != nil {
-		return err
-	}
-	return s.conf.IrmaConfiguration.Revocation.Revoke(credid, key, rsk)
+	return s.conf.IrmaConfiguration.Revocation.Revoke(credid, key)
 }
 
 func ParsePath(path string) (token, noun string, arg []string, err error) {
@@ -382,20 +371,31 @@ func (s *Server) handleClientMessage(
 func (s *Server) handleRevocationMessage(
 	noun, method string, args []string, headers map[string][]string, message []byte,
 ) (int, []byte) {
-	if (noun == "updatefrom" || noun == "updatelatest") && method == http.MethodGet {
+	if (noun == "updatefrom") && method == http.MethodGet {
 		if len(args) != 2 {
-			return server.BinaryResponse(nil, server.RemoteError(server.ErrorInvalidRequest, "GET "+noun+" expects 2 url arguments"))
+			return server.BinaryResponse(nil, server.RemoteError(server.ErrorInvalidRequest, "GET updatefrom expects 3 url arguments"))
 		}
 		i, err := strconv.ParseUint(args[1], 10, 64)
 		if err != nil {
 			return server.BinaryResponse(nil, server.RemoteError(server.ErrorMalformedInput, err.Error()))
 		}
+		pkindex, err := strconv.ParseUint(args[2], 10, 32)
+		if err != nil {
+			return server.BinaryResponse(nil, server.RemoteError(server.ErrorMalformedInput, err.Error()))
+		}
 		cred := irma.NewCredentialTypeIdentifier(args[0])
-		if noun == "updatefrom" {
-			return server.BinaryResponse(s.handleGetUpdateFrom(cred, i))
-		} else {
-			return server.BinaryResponse(s.handleGetUpdateLatest(cred, i))
+		return server.BinaryResponse(s.handleGetUpdateFrom(cred, uint(pkindex), i))
+	}
+	if noun == "updatelatest" && method == http.MethodGet {
+		if len(args) != 2 {
+			return server.BinaryResponse(nil, server.RemoteError(server.ErrorInvalidRequest, "GET updatelatest expects 2 url arguments"))
+		}
+		i, err := strconv.ParseUint(args[1], 10, 64)
+		if err != nil {
+			return server.BinaryResponse(nil, server.RemoteError(server.ErrorMalformedInput, err.Error()))
 		}
+		cred := irma.NewCredentialTypeIdentifier(args[0])
+		return server.BinaryResponse(s.handleGetUpdateLatest(cred, i))
 	}
 	if noun == "update" && method == http.MethodPost {
 		if len(args) != 1 {

internal/servercore/handle.go

@@ -189,7 +189,7 @@ func (session *session) handlePostCommitments(commitments *irma.IssueCommitmentM
 	for i, cred := range request.Credentials {
 		id := cred.CredentialTypeID.IssuerIdentifier()
 		pk, _ := session.conf.IrmaConfiguration.PublicKey(id, cred.KeyCounter)
-		sk, _ := session.conf.IrmaConfiguration.PrivateKey(id)
+		sk, _ := session.conf.IrmaConfiguration.PrivateKeyLatest(id)
 		issuer := gabi.NewIssuer(sk, pk, one)
 		proof, ok := commitments.Proofs[i+discloseCount].(*gabi.ProofU)
 		if !ok {
@@ -223,15 +223,15 @@ func (s *Server) handlePostUpdate(typ irma.CredentialTypeIdentifier, update *rev
 	return nil, nil
 }
 
-// GET revocation/updatefrom/{credtype}/{index}
+// GET revocation/updatefrom/{credtype}/{pkindex}/{index}
 func (s *Server) handleGetUpdateFrom(
-	cred irma.CredentialTypeIdentifier, index uint64,
+	cred irma.CredentialTypeIdentifier, pkindex uint, index uint64,
 ) (*revocation.Update, *irma.RemoteError) {
 	if settings := s.conf.RevocationSettings[cred]; settings == nil ||
 		!(settings.Mode == irma.RevocationModeProxy || settings.Mode == irma.RevocationModeServer) {
 		return nil, server.RemoteError(server.ErrorInvalidRequest, "not supported by this server")
 	}
-	update, err := s.conf.IrmaConfiguration.Revocation.UpdateFrom(cred, index)
+	update, err := s.conf.IrmaConfiguration.Revocation.UpdateFrom(cred, pkindex, index)
 	if err != nil {
 		return nil, server.RemoteError(server.ErrorUnknown, err.Error()) // TODO error type
 	}
@@ -241,7 +241,7 @@ func (s *Server) handleGetUpdateFrom(
 // GET revocation/updatelatest/{credtype}/{count}
 func (s *Server) handleGetUpdateLatest(
 	cred irma.CredentialTypeIdentifier, count uint64,
-) (*revocation.Update, *irma.RemoteError) {
+) (map[uint]*revocation.Update, *irma.RemoteError) {
 	if settings := s.conf.RevocationSettings[cred]; settings == nil ||
 		!(settings.Mode == irma.RevocationModeProxy || settings.Mode == irma.RevocationModeServer) {
 		return nil, server.RemoteError(server.ErrorInvalidRequest, "not supported by this server")

internal/servercore/helpers.go

@@ -95,10 +95,14 @@ func (session *session) issuanceHandleRevocation(
 
 	// Fetch latest revocation record, and then extract the current value of the accumulator
 	// from it to generate the witness from
-	u, err := rs.UpdateLatest(id, 0)
+	updates, err := rs.UpdateLatest(id, 0)
 	if err != nil {
 		return
 	}
+	u := updates[uint(cred.KeyCounter)]
+	if u == nil {
+		return nil, nil, errors.Errorf("no revocation updates found for key %d", cred.KeyCounter)
+	}
 	sig := u.SignedAccumulator
 	pk, err := rs.Keys.PublicKey(id.IssuerIdentifier(), sig.PKIndex)
 	if err != nil {
@@ -117,6 +121,7 @@ func (session *session) issuanceHandleRevocation(
 	nonrevAttr = witness.E
 	issrecord := &irma.IssuanceRecord{
 		CredType:   id,
+		PKIndex:    sk.Counter,
 		Key:        cred.RevocationKey,
 		Attr:       (*irma.RevocationAttribute)(nonrevAttr),
 		Issued:     time.Now().UnixNano(), // or (floored) cred issuance time?
@@ -130,7 +135,7 @@ func (s *Server) validateIssuanceRequest(request *irma.IssuanceRequest) error {
 	for _, cred := range request.Credentials {
 		// Check that we have the appropriate private key
 		iss := cred.CredentialTypeID.IssuerIdentifier()
-		privatekey, err := s.conf.IrmaConfiguration.PrivateKey(iss)
+		privatekey, err := s.conf.IrmaConfiguration.PrivateKeyLatest(iss)
 		if err != nil {
 			return err
 		}

internal/sessiontest/server_test.go

@@ -59,10 +59,9 @@ func StartRevocationServer(t *testing.T) {
 	var err error
 
 	irma.Logger = logger
-	dbstr := "host=127.0.0.1 port=5432 user=testuser dbname=test password='testpassword' sslmode=disable"
-	dbtype := "postgres"
-	//dbstr := "testuser:testpassword@tcp(127.0.0.1)/test"
-	//dbtype := "mysql"
+
+	//dbtype, dbstr := "postgres", "host=127.0.0.1 port=5432 user=testuser dbname=test password='testpassword' sslmode=disable"
+	dbtype, dbstr := "mysql", "testuser:testpassword@tcp(127.0.0.1)/test"
 	cred := irma.NewCredentialTypeIdentifier("irma-demo.MijnOverheid.root")
 	settings := map[irma.CredentialTypeIdentifier]*irma.RevocationSetting{
 		cred: {Mode: irma.RevocationModeServer},
@@ -97,7 +96,7 @@ func StartRevocationServer(t *testing.T) {
 	require.NoError(t, g.Close())
 
 	// Enable revocation for our credential type
-	sk, err := irmaconf.Revocation.Keys.PrivateKey(cred.IssuerIdentifier())
+	sk, err := irmaconf.Revocation.Keys.PrivateKeyLatest(cred.IssuerIdentifier())
 	require.NoError(t, err)
 	require.NoError(t, irmaconf.Revocation.EnableRevocation(cred, sk))
 

irmaclient/credential.go

 package irmaclient
 
 import (
+	"github.com/go-errors/errors"
 	"github.com/privacybydesign/gabi"
 	"github.com/privacybydesign/gabi/revocation"
 	"github.com/privacybydesign/irmago"
@@ -57,20 +58,28 @@ func (cred *credential) NonrevPrepare(conf *irma.Configuration, request irma.Ses
 	}
 
 	// first try to update witness by applying the revocation update messages attached to the session request
-	keys := irma.RevocationKeys{Conf: conf}
-	revupdates := base.RevocationUpdates[credtype]
-	count := len(revupdates.Events)
-	updated, err := cred.NonrevApplyUpdates(revupdates, keys)
+	var (
+		keys       = irma.RevocationKeys{Conf: conf}
+		revupdates = base.RevocationUpdates[credtype][cred.Pk.Counter]
+		updated    bool
+		err        error
+	)
+	if revupdates == nil {
+		return false, errors.Errorf("revocation updates for key %d not found in session request", cred.Pk.Counter)
+	}
+	updated, err = cred.NonrevApplyUpdates(revupdates, keys)
 	if err != nil {
 		return updated, err
 	}
+	count := len(revupdates.Events)
 	if cred.NonRevocationWitness.Accumulator.Index >= revupdates.Events[count-1].Index {
 		return updated, nil
 	}
 
 	// nonrevocation witness is still out of date after applying the updates from the request:
 	// we were too far behind. Update from revocation server.
-	revupdates, err = irma.RevocationClient{Conf: conf}.FetchUpdateFrom(credtype, cred.NonRevocationWitness.Accumulator.Index+1)
+	revupdates, err = irma.RevocationClient{Conf: conf}.
+		FetchUpdateFrom(credtype, cred.Pk.Counter, cred.NonRevocationWitness.Accumulator.Index+1)
 	if err != nil {
 		return updated, err
 	}

irmaconfig.go

@@ -48,7 +48,7 @@ type Configuration struct {
 
 	// Issuer private keys. If set (after calling ParseFolder()), will use these keys
 	// instead of keys in irma_configuration/$issuer/PrivateKeys.
-	PrivateKeys map[IssuerIdentifier]*gabi.PrivateKey
+	PrivateKeys map[IssuerIdentifier]map[int]*gabi.PrivateKey
 
 	Revocation *RevocationStorage
 
@@ -166,7 +166,7 @@ func (conf *Configuration) clear() {
 	conf.DisabledSchemeManagers = make(map[SchemeManagerIdentifier]*SchemeManagerError)
 	conf.kssPublicKeys = make(map[SchemeManagerIdentifier]map[int]*rsa.PublicKey)
 	conf.publicKeys = make(map[IssuerIdentifier]map[int]*gabi.PublicKey)
-	conf.PrivateKeys = make(map[IssuerIdentifier]*gabi.PrivateKey)
+	conf.PrivateKeys = make(map[IssuerIdentifier]map[int]*gabi.PrivateKey)
 	conf.reverseHashes = make(map[string]CredentialTypeIdentifier)
 }
 
@@ -320,47 +320,42 @@ func (conf *Configuration) ParseSchemeManagerFolder(dir string, manager *SchemeM
 	return
 }
 
-// PrivateKey returns the latest private key of the specified issuer, or nil if not present in the Configuration.
-func (conf *Configuration) PrivateKey(id IssuerIdentifier) (*gabi.PrivateKey, error) {
-	if sk := conf.PrivateKeys[id]; sk != nil {
-		return sk, nil
+// PrivateKey returns the specified private key of the specified issuer if present; an error otherwise.
+func (conf *Configuration) PrivateKey(id IssuerIdentifier, counter int) (*gabi.PrivateKey, error) {
+	if _, haveIssuer := conf.PrivateKeys[id]; haveIssuer {
+		if sk := conf.PrivateKeys[id][counter]; sk != nil {
+			return sk, nil
+		}
 	}
 
 	path := fmt.Sprintf(privkeyPattern, conf.Path, id.SchemeManagerIdentifier().Name(), id.Name())
-	files, err := filepath.Glob(path)
+	file := strings.Replace(path, "*", strconv.Itoa(counter), 1)
+	sk, err := gabi.NewPrivateKeyFromFile(file)
 	if err != nil {
 		return nil, err
 	}
-	if len(files) == 0 {
-		return nil, nil
+	if int(sk.Counter) != counter {
+		return nil, errors.Errorf("Private key %s of issuer %s has wrong <Counter>", file, id.String())
 	}
 
-	// List private keys and get highest counter
-	counters := make([]int, 0, len(files))
-	for _, file := range files {
-		filename := filepath.Base(file)
-		count := filename[:len(filename)-4]
-		i, err := strconv.Atoi(count)
-		if err != nil {
-			return nil, err
-		}
-		counters = append(counters, i)
+	if conf.PrivateKeys[id] == nil {
+		conf.PrivateKeys[id] = make(map[int]*gabi.PrivateKey)
 	}
-	sort.Ints(counters)
-	counter := counters[len(counters)-1]
+	conf.PrivateKeys[id][counter] = sk
 
-	// Read private key
-	file := strings.Replace(path, "*", strconv.Itoa(counter), 1)
-	sk, err := gabi.NewPrivateKeyFromFile(file)
+	return sk, nil
+}
+
+// PrivateKeyLatest returns the latest private key of the specified issuer, or nil if not present in the Configuration.
+func (conf *Configuration) PrivateKeyLatest(id IssuerIdentifier) (*gabi.PrivateKey, error) {
+	indices, err := conf.PrivateKeyIndices(id)
 	if err != nil {
 		return nil, err
 	}
-	if int(sk.Counter) != counter {
-		return nil, errors.Errorf("Private key %s of issuer %s has wrong <Counter>", file, id.String())
+	if len(indices) == 0 {
+		return nil, errors.New("no private keys found")
 	}
-	conf.PrivateKeys[id] = sk
-
-	return sk, nil
+	return conf.PrivateKey(id, indices[len(indices)-1])
 }
 
 // PublicKey returns the specified public key, or nil if not present in the Configuration.
@@ -535,6 +530,10 @@ func (conf *Configuration) parseKeysFolder(issuerid IssuerIdentifier) error {
 	return nil
 }
 
+func (conf *Configuration) PrivateKeyIndices(issuerid IssuerIdentifier) (i []int, err error) {
+	return conf.matchKeyPattern(issuerid, privkeyPattern)
+}
+
 func (conf *Configuration) PublicKeyIndices(issuerid IssuerIdentifier) (i []int, err error) {
 	return conf.matchKeyPattern(issuerid, pubkeyPattern)
 }

requests.go

@@ -39,7 +39,7 @@ type BaseRequest struct {
 	Revocation []CredentialTypeIdentifier `json:"revocation,omitempty"`
 	// RevocationUpdates contains revocation update messages for the client to update its
 	// revocation state.
-	RevocationUpdates map[CredentialTypeIdentifier]*revocation.Update `json:"revocationUpdates,omitempty"`
+	RevocationUpdates map[CredentialTypeIdentifier]map[uint]*revocation.Update `json:"revocationUpdates,omitempty"`
 
 	ids *IrmaIdentifierSet // cache for Identifiers() method
 
@@ -237,7 +237,7 @@ func (b *BaseRequest) GetNonce(*atum.Timestamp) *big.Int {
 // RequestsRevocation indicates whether or not the requestor requires a nonrevocation proof for
 // the given credential type; that is, whether or not it included revocation update messages.
 func (b *BaseRequest) RequestsRevocation(id CredentialTypeIdentifier) bool {
-	return len(b.RevocationUpdates) > 0 && len(b.RevocationUpdates[id].Events) > 0
+	return len(b.RevocationUpdates) > 0 && len(b.RevocationUpdates[id]) > 0
 }
 
 func (b *BaseRequest) RevocationConsistent() error {

revocation.go

@@ -74,12 +74,13 @@ type (
 	AccumulatorRecord struct {
 		CredType CredentialTypeIdentifier `gorm:"primary_key"`
 		Data     signedMessage
-		PKIndex  uint
+		PKIndex  uint `gorm:"primary_key;auto_increment:false"`
 	}
 
 	EventRecord struct {
 		Index      uint64                   `gorm:"primary_key;column:eventindex"`
 		CredType   CredentialTypeIdentifier `gorm:"primary_key"`
+		PKIndex    uint                     `gorm:"primary_key;auto_increment:false"`
 		E          *RevocationAttribute
 		ParentHash eventHash
 	}
@@ -88,6 +89,7 @@ type (
 	IssuanceRecord struct {
 		Key        string                   `gorm:"primary_key;column:revocationkey"`
 		CredType   CredentialTypeIdentifier `gorm:"primary_key"`
+		PKIndex    uint
 		Attr       *RevocationAttribute
 		Issued     int64
 		ValidUntil int64
@@ -136,12 +138,12 @@ const (
 // only way to create such an initial accumulator and it must be called before anyone can use
 // revocation for this credential type. Requires the issuer private key.
 func (rs *RevocationStorage) EnableRevocation(typ CredentialTypeIdentifier, sk *revocation.PrivateKey) error {
-	hasRecords, err := rs.db.HasRecords(typ, (*EventRecord)(nil))
+	enabled, err := rs.RevocationEnabled(typ)
 	if err != nil {
 		return err
 	}
-	if hasRecords {
-		return errors.New("revocation event record table not empty")
+	if enabled {
+		return errors.New("revocation already enabled")
 	}
 
 	update, err := revocation.NewAccumulator(sk)
@@ -159,7 +161,7 @@ func (rs *RevocationStorage) EnableRevocation(typ CredentialTypeIdentifier, sk *
 // by checking if any revocation record exists in the database.
 func (rs *RevocationStorage) RevocationEnabled(typ CredentialTypeIdentifier) (bool, error) {
 	if rs.sqlMode {
-		return rs.db.HasRecords(typ, (*EventRecord)(nil))
+		return rs.db.Exists((*EventRecord)(nil), nil)
 	} else {
 		return rs.memdb.HasRecords(typ), nil
 	}
@@ -170,16 +172,16 @@ func (rs *RevocationStorage) RevocationEnabled(typ CredentialTypeIdentifier) (bo
 // UpdateFrom returns all records that a client requires to update its revocation state if it is currently
 // at the specified index, that is, all records whose end index is greater than or equal to
 // the specified index.
-func (rs *RevocationStorage) UpdateFrom(typ CredentialTypeIdentifier, index uint64) (*revocation.Update, error) {
+func (rs *RevocationStorage) UpdateFrom(typ CredentialTypeIdentifier, pkindex uint, index uint64) (*revocation.Update, error) {
 	// Only requires SQL implementation
 	var update *revocation.Update
 	if err := rs.db.Transaction(func(tx revStorage) error {
-		acc, _, err := rs.currentAccumulator(tx, typ)
+		acc, _, err := rs.accumulator(tx, typ, pkindex)
 		if err != nil {
 			return err
 		}
 		var events []*EventRecord
-		if err := tx.From(typ, "index", index, &events); err != nil {
+		if err := tx.From(&events, "cred_type = ? and pk_index = ? and index >= ?", typ, pkindex, index); err != nil {
 			return err
 		}
 		update = rs.newUpdate(acc, events)
@@ -190,20 +192,22 @@ func (rs *RevocationStorage) UpdateFrom(typ CredentialTypeIdentifier, index uint
 	return update, nil
 }
 
-func (rs *RevocationStorage) UpdateLatest(typ CredentialTypeIdentifier, count uint64) (*revocation.Update, error) {
+func (rs *RevocationStorage) UpdateLatest(typ CredentialTypeIdentifier, count uint64) (map[uint]*revocation.Update, error) {
 	// TODO what should this function and UpdateFrom return when no records are found?
 	if rs.sqlMode {
-		var update *revocation.Update
+		var update map[uint]*revocation.Update
 		if err := rs.db.Transaction(func(tx revStorage) error {
-			acc, _, err := rs.currentAccumulator(tx, typ)
-			if err != nil {
+			var (
+				records []*AccumulatorRecord
+				events  []*EventRecord
+			)
+			if err := tx.Last(&records, map[string]interface{}{"cred_type": typ}); err != nil {
 				return err
 			}
-			var events []*EventRecord
-			if err := tx.Latest(typ, "eventindex", count, &events); err != nil {
+			if err := tx.Latest(&events, count, map[string]interface{}{"cred_type": typ}); err != nil {
 				return err
 			}
-			update = rs.newUpdate(acc, events)
+			update = rs.newUpdates(records, events)
 			return nil
 		}); err != nil {
 			return nil, err
@@ -214,7 +218,28 @@ func (rs *RevocationStorage) UpdateLatest(typ CredentialTypeIdentifier, count ui
 	}
 }
 
-func (*RevocationStorage) newUpdate(acc *revocation.SignedAccumulator, events []*EventRecord) *revocation.Update {
+func (*RevocationStorage) newUpdates(records []*AccumulatorRecord, events []*EventRecord) map[uint]*revocation.Update {
+	accs := map[uint]*revocation.SignedAccumulator{}
+	for _, r := range records {
+		accs[r.PKIndex] = r.SignedAccumulator()
+	}
+	updates := make(map[uint]*revocation.Update, len(accs))
+	for _, e := range events {
+		i := e.PKIndex
+		if accs[i] == nil {
+			continue
+		}
+		update, present := updates[i]
+		if !present {
+			update = &revocation.Update{SignedAccumulator: accs[i]}
+			updates[i] = update
+		}
+		update.Events = append(update.Events, e.Event())
+	}
+	return updates
+}
+
+func (rs *RevocationStorage) newUpdate(acc *revocation.SignedAccumulator, events []*EventRecord) *revocation.Update {
 	updates := make([]*revocation.Event, len(events))
 	for i := range events {
 		updates[i] = events[i].Event()
@@ -249,7 +274,7 @@ func (rs *RevocationStorage) addUpdate(tx revStorage, typ CredentialTypeIdentifi
 			return err
 		}
 		for _, event := range update.Events {
-			if err = tx.Insert(new(EventRecord).Convert(typ, event)); err != nil {
+			if err = tx.Insert(new(EventRecord).Convert(typ, update.SignedAccumulator.PKIndex, event)); err != nil {
 				return err
 			}
 		}
@@ -268,7 +293,7 @@ func (rs *RevocationStorage) addUpdate(tx revStorage, typ CredentialTypeIdentifi
 // Issuance records
 
 func (rs *RevocationStorage) IssuanceRecordExists(typ CredentialTypeIdentifier, key []byte) (bool, error) {
-	return rs.db.Exists(typ, "key", key, &IssuanceRecord{})
+	return rs.db.Exists(&IssuanceRecord{}, map[string]interface{}{"cred_type": typ, "revocationkey": key})
 }
 
 func (rs *RevocationStorage) AddIssuanceRecord(r *IssuanceRecord) error {
@@ -277,7 +302,7 @@ func (rs *RevocationStorage) AddIssuanceRecord(r *IssuanceRecord) error {
 
 func (rs *RevocationStorage) IssuanceRecord(typ CredentialTypeIdentifier, key []byte) (*IssuanceRecord, error) {
 	var r IssuanceRecord
-	err := rs.db.Get(typ, "key", key, &r)
+	err := rs.db.Last(&r, map[string]interface{}{"cred_type": typ, "revocationkey": key})
 	if err != nil {
 		return nil, err
 	}
@@ -289,7 +314,7 @@ func (rs *RevocationStorage) IssuanceRecord(typ CredentialTypeIdentifier, key []
 // Revoke revokes the credential specified by key if found within the current database,
 // by updating its revocation time to now, removing its revocation attribute from the current accumulator,
 // and updating the revocation database on disk.
-func (rs *RevocationStorage) Revoke(typ CredentialTypeIdentifier, key string, sk *revocation.PrivateKey) error {
+func (rs *RevocationStorage) Revoke(typ CredentialTypeIdentifier, key string) error {
 	if rs.getSettings(typ).Mode != RevocationModeServer {
 		return errors.Errorf("cannot revoke %s", typ)
 	}
@@ -297,19 +322,23 @@ func (rs *RevocationStorage) Revoke(typ CredentialTypeIdentifier, key string, sk
 	return rs.db.Transaction(func(tx revStorage) error {
 		var err error
 		issrecord := IssuanceRecord{}
-		if err = tx.Get(typ, "revocationkey", key, &issrecord); err != nil {
+		if err = tx.Last(&issrecord, map[string]interface{}{"cred_type": typ, "revocationkey": key}); err != nil {
 			return err
 		}
 		issrecord.RevokedAt = time.Now().UnixNano()
 		if err = tx.Save(&issrecord); err != nil {
 			return err
 		}
+		sk, err := rs.Keys.PrivateKey(typ.IssuerIdentifier(), issrecord.PKIndex)
+		if err != nil {
+			return err
+		}
 		return rs.revokeAttr(tx, typ, sk, issrecord.Attr)
 	})
 }
 
 func (rs *RevocationStorage) revokeAttr(tx revStorage, typ CredentialTypeIdentifier, sk *revocation.PrivateKey, e *RevocationAttribute) error {
-	_, cur, err := rs.currentAccumulator(tx, typ)
+	_, cur, err := rs.accumulator(tx, typ, sk.Counter)
 	if err != nil {
 		return err
 	}
@@ -317,7 +346,7 @@ func (rs *RevocationStorage) revokeAttr(tx revStorage, typ CredentialTypeIdentif
 		return errors.Errorf("cannot revoke for type %s, not enabled yet", typ)
 	}
 	var parent EventRecord
-	if err = rs.db.Last(typ, &parent); err != nil {
+	if err = rs.db.Last(&parent, map[string]interface{}{"cred_type": typ, "pk_index": sk.Counter}); err != nil {
 		return err
 	}
 
@@ -333,25 +362,25 @@ func (rs *RevocationStorage) revokeAttr(tx revStorage, typ CredentialTypeIdentif
 
 // Accumulator methods
 
-func (rs *RevocationStorage) currentAccumulator(tx revStorage, typ CredentialTypeIdentifier) (
+// accumulator retrieves, verifies and deserializes the accumulator of the given type and key.
+func (rs *RevocationStorage) accumulator(tx revStorage, typ CredentialTypeIdentifier, pkindex uint) (
 	*revocation.SignedAccumulator, *revocation.Accumulator, error,
 ) {
 	var err error
 	var sacc *revocation.SignedAccumulator
 	if rs.sqlMode {
 		record := &AccumulatorRecord{}
-		if err = tx.Last(typ, record); err != nil {
+		if err = tx.Last(record, map[string]interface{}{"cred_type": typ, "pk_index": pkindex}); err != nil {
 			if gorm.IsRecordNotFoundError(err) {
 				return nil, nil, nil
 			}
 		}
 		sacc = record.SignedAccumulator()
 	} else {
-		u := rs.memdb.Latest(typ, 0)
-		if u == nil {
+		sacc = rs.memdb.SignedAccumulator(typ, pkindex)
+		if sacc == nil {
 			return nil, nil, nil
 		}
-		sacc = u.SignedAccumulator
 	}
 
 	pk, err := rs.Keys.PublicKey(typ.IssuerIdentifier(), sacc.PKIndex)
@@ -368,15 +397,15 @@ func (rs *RevocationStorage) currentAccumulator(tx revStorage, typ CredentialTyp
 // Methods to update from remote revocation server
 
 func (rs *RevocationStorage) UpdateDB(typ CredentialTypeIdentifier) error {
-	update, err := rs.client.FetchUpdateLatest(typ, revocationUpdateCount)
+	updates, err := rs.client.FetchUpdateLatest(typ, revocationUpdateCount)
 	if err != nil {
 		return err
 	}
-
-	if err = rs.AddUpdate(typ, update); err != nil {
-		return err
+	for _, u := range updates {
+		if err = rs.AddUpdate(typ, u); err != nil {
+			return err
+		}
 	}
-
 	// bump updated even if no new records were added
 	rs.getSettings(typ).updated = time.Now()
 	return nil
@@ -489,7 +518,7 @@ func (rs *RevocationStorage) SetRevocationUpdates(b *BaseRequest) error {
 		return nil
 	}
 	var err error
-	b.RevocationUpdates = make(map[CredentialTypeIdentifier]*revocation.Update, len(b.Revocation))
+	b.RevocationUpdates = make(map[CredentialTypeIdentifier]map[uint]*revocation.Update, len(b.Revocation))
 	for _, credid := range b.Revocation {
 		if !rs.conf.CredentialTypes[credid].SupportsRevocation() {
 			return errors.Errorf("cannot request nonrevocation proof for %s: revocation not enabled in scheme")
@@ -549,36 +578,59 @@ func (client RevocationClient) PostIssuanceRecord(typ CredentialTypeIdentifier,
 }
 
 // FetchRevocationRecords gets revocation update messages from the revocation server, of the specified index and greater.
-func (client RevocationClient) FetchUpdateFrom(typ CredentialTypeIdentifier, index uint64) (*revocation.Update, error) {
-	return client.fetchUpdate(typ, "updatefrom", index)
+func (client RevocationClient) FetchUpdateFrom(typ CredentialTypeIdentifier, pkindex uint, index uint64) (*revocation.Update, error) {
+	update := &revocation.Update{}
+	return update, client.getMultiple(
+		client.Conf.CredentialTypes[typ].RevocationServers,
+		fmt.Sprintf("revocation/updatefrom/%s/%d/%d", typ, pkindex, index),
+		&update,
+	)
 }
 
-func (client RevocationClient) FetchUpdateLatest(typ CredentialTypeIdentifier, count uint64) (*revocation.Update, error) {
-	return client.fetchUpdate(typ, "updatelatest", count)
+func (client RevocationClient) FetchUpdateLatest(typ CredentialTypeIdentifier, count uint64) (map[uint]*revocation.Update, error) {
+	update := map[uint]*revocation.Update{}
+	return update, client.getMultiple(
+		client.Conf.CredentialTypes[typ].RevocationServers,
+		fmt.Sprintf("revocation/updatelatest/%s/%d", typ, count),
+		&update,
+	)
 }
 
-func (client RevocationClient) fetchUpdate(typ CredentialTypeIdentifier, u string, i uint64) (*revocation.Update, error) {
+func (RevocationClient) getMultiple(urls []string, path string, dest interface{}) error {
 	var (
-		err       error
 		errs      multierror.Error
-		update    = &revocation.Update{}
 		transport = NewHTTPTransport("")