diff --git a/iam/converter.go b/iam/converter.go
index d6642f3..b781823 100644
--- a/iam/converter.go
+++ b/iam/converter.go
@@ -6,7 +6,7 @@ import (
 	"strings"
 	"time"
 
-	policyengine "git.frostfs.info/TrueCloudLab/policy-engine"
+	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/chain"
 )
 
 const (
@@ -52,41 +52,41 @@ const (
 	CondArnNotLike   string = "ArnNotLike"
 )
 
-func (p Policy) ToChain() (*policyengine.Chain, error) {
+func (p Policy) ToChain() (*chain.Chain, error) {
 	if err := p.Validate(GeneralPolicyType); err != nil {
 		return nil, err
 	}
 
-	var chain policyengine.Chain
+	var ch chain.Chain
 
 	for _, statement := range p.Statement {
-		status := policyengine.AccessDenied
+		status := chain.AccessDenied
 		if statement.Effect == AllowEffect {
-			status = policyengine.Allow
+			status = chain.Allow
 		}
 
 		var principals []string
-		var op policyengine.ConditionType
+		var op chain.ConditionType
 		statementPrincipal, inverted := statement.principal()
 		if _, ok := statementPrincipal[Wildcard]; ok { // this can be true only if 'inverted' false
 			principals = []string{Wildcard}
-			op = policyengine.CondStringLike
+			op = chain.CondStringLike
 		} else {
 			for _, principal := range statementPrincipal {
 				principals = append(principals, principal...)
 			}
 
-			op = policyengine.CondStringEquals
+			op = chain.CondStringEquals
 			if inverted {
-				op = policyengine.CondStringNotEquals
+				op = chain.CondStringNotEquals
 			}
 		}
 
-		var conditions []policyengine.Condition
+		var conditions []chain.Condition
 		for _, principal := range principals {
-			conditions = append(conditions, policyengine.Condition{
+			conditions = append(conditions, chain.Condition{
 				Op:     op,
-				Object: policyengine.ObjectRequest,
+				Object: chain.ObjectRequest,
 				Key:    RequestOwnerProperty,
 				Value:  principal,
 			})
@@ -99,49 +99,49 @@ func (p Policy) ToChain() (*policyengine.Chain, error) {
 		conditions = append(conditions, conds...)
 
 		action, actionInverted := statement.action()
-		ruleAction := policyengine.Actions{Inverted: actionInverted, Names: action}
+		ruleAction := chain.Actions{Inverted: actionInverted, Names: action}
 
 		resource, resourceInverted := statement.resource()
-		ruleResource := policyengine.Resources{Inverted: resourceInverted, Names: resource}
+		ruleResource := chain.Resources{Inverted: resourceInverted, Names: resource}
 
-		r := policyengine.Rule{
+		r := chain.Rule{
 			Status:    status,
 			Actions:   ruleAction,
 			Resources: ruleResource,
 			Any:       true,
 			Condition: conditions,
 		}
-		chain.Rules = append(chain.Rules, r)
+		ch.Rules = append(ch.Rules, r)
 	}
 
-	return &chain, nil
+	return &ch, nil
 }
 
 //nolint:funlen
-func (c Conditions) ToChainCondition() ([]policyengine.Condition, error) {
-	var conditions []policyengine.Condition
+func (c Conditions) ToChainCondition() ([]chain.Condition, error) {
+	var conditions []chain.Condition
 
 	var convertValue convertFunction
 
 	for op, KVs := range c {
-		var condType policyengine.ConditionType
+		var condType chain.ConditionType
 
 		switch {
 		case strings.HasPrefix(op, "String"):
 			convertValue = noConvertFunction
 			switch op {
 			case CondStringEquals:
-				condType = policyengine.CondStringEquals
+				condType = chain.CondStringEquals
 			case CondStringNotEquals:
-				condType = policyengine.CondStringNotEquals
+				condType = chain.CondStringNotEquals
 			case CondStringEqualsIgnoreCase:
-				condType = policyengine.CondStringEqualsIgnoreCase
+				condType = chain.CondStringEqualsIgnoreCase
 			case CondStringNotEqualsIgnoreCase:
-				condType = policyengine.CondStringNotEqualsIgnoreCase
+				condType = chain.CondStringNotEqualsIgnoreCase
 			case CondStringLike:
-				condType = policyengine.CondStringLike
+				condType = chain.CondStringLike
 			case CondStringNotLike:
-				condType = policyengine.CondStringNotLike
+				condType = chain.CondStringNotLike
 			default:
 				return nil, fmt.Errorf("unsupported condition operator: '%s'", op)
 			}
@@ -149,13 +149,13 @@ func (c Conditions) ToChainCondition() ([]policyengine.Condition, error) {
 			convertValue = noConvertFunction
 			switch op {
 			case CondArnEquals:
-				condType = policyengine.CondStringEquals
+				condType = chain.CondStringEquals
 			case CondArnNotEquals:
-				condType = policyengine.CondStringNotEquals
+				condType = chain.CondStringNotEquals
 			case CondArnLike:
-				condType = policyengine.CondStringLike
+				condType = chain.CondStringLike
 			case CondArnNotLike:
-				condType = policyengine.CondStringNotLike
+				condType = chain.CondStringNotLike
 			default:
 				return nil, fmt.Errorf("unsupported condition operator: '%s'", op)
 			}
@@ -165,33 +165,33 @@ func (c Conditions) ToChainCondition() ([]policyengine.Condition, error) {
 			convertValue = dateConvertFunction
 			switch op {
 			case CondDateEquals:
-				condType = policyengine.CondStringEquals
+				condType = chain.CondStringEquals
 			case CondDateNotEquals:
-				condType = policyengine.CondStringNotEquals
+				condType = chain.CondStringNotEquals
 			case CondDateLessThan:
-				condType = policyengine.CondStringLessThan
+				condType = chain.CondStringLessThan
 			case CondDateLessThanEquals:
-				condType = policyengine.CondStringLessThanEquals
+				condType = chain.CondStringLessThanEquals
 			case CondDateGreaterThan:
-				condType = policyengine.CondStringGreaterThan
+				condType = chain.CondStringGreaterThan
 			case CondDateGreaterThanEquals:
-				condType = policyengine.CondStringGreaterThanEquals
+				condType = chain.CondStringGreaterThanEquals
 			default:
 				return nil, fmt.Errorf("unsupported condition operator: '%s'", op)
 			}
 		case op == CondBool:
 			convertValue = noConvertFunction
-			condType = policyengine.CondStringEqualsIgnoreCase
+			condType = chain.CondStringEqualsIgnoreCase
 		case op == CondIPAddress:
 			// todo consider using converters
 			//  "203.0.113.0/24" -> "203.0.113.*",
 			//  "2001:DB8:1234:5678::/64" -> "2001:DB8:1234:5678:*"
 			//  or having specific condition type for IP
 			convertValue = noConvertFunction
-			condType = policyengine.CondStringLike
+			condType = chain.CondStringLike
 		case op == CondNotIPAddress:
 			convertValue = noConvertFunction
-			condType = policyengine.CondStringNotLike
+			condType = chain.CondStringNotLike
 		default:
 			return nil, fmt.Errorf("unsupported condition operator: '%s'", op)
 		}
@@ -203,9 +203,9 @@ func (c Conditions) ToChainCondition() ([]policyengine.Condition, error) {
 					return nil, err
 				}
 
-				conditions = append(conditions, policyengine.Condition{
+				conditions = append(conditions, chain.Condition{
 					Op:     condType,
-					Object: policyengine.ObjectRequest,
+					Object: chain.ObjectRequest,
 					Key:    key,
 					Value:  converted,
 				})
diff --git a/iam/converter_test.go b/iam/converter_test.go
index 3de9cb5..27fcc04 100644
--- a/iam/converter_test.go
+++ b/iam/converter_test.go
@@ -3,7 +3,7 @@ package iam
 import (
 	"testing"
 
-	policyengine "git.frostfs.info/TrueCloudLab/policy-engine"
+	chain "git.frostfs.info/TrueCloudLab/policy-engine/pkg/chain"
 	"github.com/stretchr/testify/require"
 )
 
@@ -26,22 +26,22 @@ func TestConverters(t *testing.T) {
 			}},
 		}
 
-		expected := &policyengine.Chain{Rules: []policyengine.Rule{
+		expected := &chain.Chain{Rules: []chain.Rule{
 			{
-				Status:    policyengine.Allow,
-				Actions:   policyengine.Actions{Names: p.Statement[0].Action},
-				Resources: policyengine.Resources{Names: p.Statement[0].Resource},
+				Status:    chain.Allow,
+				Actions:   chain.Actions{Names: p.Statement[0].Action},
+				Resources: chain.Resources{Names: p.Statement[0].Resource},
 				Any:       true,
-				Condition: []policyengine.Condition{
+				Condition: []chain.Condition{
 					{
-						Op:     policyengine.CondStringEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringEquals,
+						Object: chain.ObjectRequest,
 						Key:    RequestOwnerProperty,
 						Value:  "arn:aws:iam::111122223333:user/JohnDoe",
 					},
 					{
-						Op:     policyengine.CondStringEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringEquals,
+						Object: chain.ObjectRequest,
 						Key:    "s3:RequestObjectTag/Department",
 						Value:  "Finance",
 					},
@@ -67,16 +67,16 @@ func TestConverters(t *testing.T) {
 			}},
 		}
 
-		expected := &policyengine.Chain{Rules: []policyengine.Rule{
+		expected := &chain.Chain{Rules: []chain.Rule{
 			{
-				Status:    policyengine.AccessDenied,
-				Actions:   policyengine.Actions{Inverted: true, Names: p.Statement[0].NotAction},
-				Resources: policyengine.Resources{Inverted: true, Names: p.Statement[0].NotResource},
+				Status:    chain.AccessDenied,
+				Actions:   chain.Actions{Inverted: true, Names: p.Statement[0].NotAction},
+				Resources: chain.Resources{Inverted: true, Names: p.Statement[0].NotResource},
 				Any:       true,
-				Condition: []policyengine.Condition{
+				Condition: []chain.Condition{
 					{
-						Op:     policyengine.CondStringNotEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringNotEquals,
+						Object: chain.ObjectRequest,
 						Key:    RequestOwnerProperty,
 						Value:  "arn:aws:iam::111122223333:user/JohnDoe",
 					},
@@ -154,136 +154,136 @@ func TestConverters(t *testing.T) {
 			}},
 		}
 
-		expected := &policyengine.Chain{Rules: []policyengine.Rule{
+		expected := &chain.Chain{Rules: []chain.Rule{
 			{
-				Status:    policyengine.Allow,
-				Actions:   policyengine.Actions{Names: p.Statement[0].Action},
-				Resources: policyengine.Resources{Names: p.Statement[0].Resource},
+				Status:    chain.Allow,
+				Actions:   chain.Actions{Names: p.Statement[0].Action},
+				Resources: chain.Resources{Names: p.Statement[0].Resource},
 				Any:       true,
-				Condition: []policyengine.Condition{
+				Condition: []chain.Condition{
 					{
-						Op:     policyengine.CondStringLike,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringLike,
+						Object: chain.ObjectRequest,
 						Key:    RequestOwnerProperty,
 						Value:  "*",
 					},
 					{
-						Op:     policyengine.CondStringEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringEquals,
+						Object: chain.ObjectRequest,
 						Key:    "key1",
 						Value:  "val0",
 					},
 					{
-						Op:     policyengine.CondStringEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringEquals,
+						Object: chain.ObjectRequest,
 						Key:    "key1",
 						Value:  "val1",
 					},
 					{
-						Op:     policyengine.CondStringNotEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringNotEquals,
+						Object: chain.ObjectRequest,
 						Key:    "key2",
 						Value:  "val2",
 					},
 					{
-						Op:     policyengine.CondStringEqualsIgnoreCase,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringEqualsIgnoreCase,
+						Object: chain.ObjectRequest,
 						Key:    "key3",
 						Value:  "val3",
 					},
 					{
-						Op:     policyengine.CondStringNotEqualsIgnoreCase,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringNotEqualsIgnoreCase,
+						Object: chain.ObjectRequest,
 						Key:    "key4",
 						Value:  "val4",
 					},
 					{
-						Op:     policyengine.CondStringLike,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringLike,
+						Object: chain.ObjectRequest,
 						Key:    "key5",
 						Value:  "val5",
 					},
 					{
-						Op:     policyengine.CondStringNotLike,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringNotLike,
+						Object: chain.ObjectRequest,
 						Key:    "key6",
 						Value:  "val6",
 					},
 					{
-						Op:     policyengine.CondStringEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringEquals,
+						Object: chain.ObjectRequest,
 						Key:    "key7",
 						Value:  "1136189045",
 					},
 					{
-						Op:     policyengine.CondStringNotEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringNotEquals,
+						Object: chain.ObjectRequest,
 						Key:    "key8",
 						Value:  "1136214245",
 					},
 					{
-						Op:     policyengine.CondStringLessThan,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringLessThan,
+						Object: chain.ObjectRequest,
 						Key:    "key9",
 						Value:  "1136192645",
 					},
 					{
-						Op:     policyengine.CondStringLessThanEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringLessThanEquals,
+						Object: chain.ObjectRequest,
 						Key:    "key10",
 						Value:  "1136203445",
 					},
 					{
-						Op:     policyengine.CondStringGreaterThan,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringGreaterThan,
+						Object: chain.ObjectRequest,
 						Key:    "key11",
 						Value:  "1136217845",
 					},
 					{
-						Op:     policyengine.CondStringGreaterThanEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringGreaterThanEquals,
+						Object: chain.ObjectRequest,
 						Key:    "key12",
 						Value:  "1136225045",
 					},
 					{
-						Op:     policyengine.CondStringEqualsIgnoreCase,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringEqualsIgnoreCase,
+						Object: chain.ObjectRequest,
 						Key:    "key13",
 						Value:  "True",
 					},
 					{
-						Op:     policyengine.CondStringLike,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringLike,
+						Object: chain.ObjectRequest,
 						Key:    "key14",
 						Value:  "val14",
 					},
 					{
-						Op:     policyengine.CondStringNotLike,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringNotLike,
+						Object: chain.ObjectRequest,
 						Key:    "key15",
 						Value:  "val15",
 					},
 					{
-						Op:     policyengine.CondStringEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringEquals,
+						Object: chain.ObjectRequest,
 						Key:    "key16",
 						Value:  "val16",
 					},
 					{
-						Op:     policyengine.CondStringLike,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringLike,
+						Object: chain.ObjectRequest,
 						Key:    "key17",
 						Value:  "val17",
 					},
 					{
-						Op:     policyengine.CondStringNotEquals,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringNotEquals,
+						Object: chain.ObjectRequest,
 						Key:    "key18",
 						Value:  "val18",
 					},
 					{
-						Op:     policyengine.CondStringNotLike,
-						Object: policyengine.ObjectRequest,
+						Op:     chain.CondStringNotLike,
+						Object: chain.ObjectRequest,
 						Key:    "key19",
 						Value:  "val19",
 					},
diff --git a/inmemory.go b/inmemory.go
deleted file mode 100644
index 50c146d..0000000
--- a/inmemory.go
+++ /dev/null
@@ -1,110 +0,0 @@
-package policyengine
-
-import (
-	"git.frostfs.info/TrueCloudLab/policy-engine/util"
-)
-
-type inmemory struct {
-	namespace map[Name][]chain
-	resource  map[Name][]chain
-	local     map[Name][]*Chain
-}
-
-type chain struct {
-	object string
-	chain  *Chain
-}
-
-// NewInMemory returns new inmemory instance of chain storage.
-func NewInMemory() CachedChainStorage {
-	return &inmemory{
-		namespace: make(map[Name][]chain),
-		resource:  make(map[Name][]chain),
-		local:     make(map[Name][]*Chain),
-	}
-}
-
-// IsAllowed implements the Engine interface.
-func (s *inmemory) IsAllowed(name Name, namespace string, r Request) (Status, bool) {
-	var ruleFound bool
-	if local, ok := s.local[name]; ok {
-		for _, c := range local {
-			if status, matched := c.Match(r); matched && status != Allow {
-				return status, true
-			}
-		}
-	}
-	if cs, ok := s.namespace[name]; ok {
-		status, ok := matchArray(cs, namespace, r)
-		if ok && status != Allow {
-			return status, true
-		}
-		ruleFound = ruleFound || ok
-	}
-	if cs, ok := s.resource[name]; ok {
-		status, ok := matchArray(cs, r.Resource().Name(), r)
-		if ok {
-			return status, true
-		}
-		ruleFound = ruleFound || ok
-	}
-	if ruleFound {
-		return Allow, true
-	}
-	return NoRuleFound, false
-}
-
-func matchArray(cs []chain, object string, r Request) (Status, bool) {
-	for _, c := range cs {
-		if !util.GlobMatch(object, c.object) {
-			continue
-		}
-		if status, matched := c.chain.Match(r); matched {
-			return status, true
-		}
-	}
-	return NoRuleFound, false
-}
-
-func (s *inmemory) AddResourceChain(name Name, resource string, c *Chain) {
-	s.resource[name] = append(s.resource[name], chain{resource, c})
-}
-
-func (s *inmemory) AddNameSpaceChain(name Name, namespace string, c *Chain) {
-	s.namespace[name] = append(s.namespace[name], chain{namespace, c})
-}
-
-func (s *inmemory) AddOverride(name Name, c *Chain) {
-	s.local[name] = append(s.local[name], c)
-}
-
-func (s *inmemory) GetOverride(name Name, chainID ChainID) (chain *Chain, found bool) {
-	chains := s.local[name]
-
-	for _, chain = range chains {
-		if chain.ID == chainID {
-			found = true
-			return
-		}
-	}
-
-	return
-}
-
-func (s *inmemory) RemoveOverride(name Name, chainID ChainID) (found bool) {
-	chains := s.local[name]
-
-	for i, chain := range chains {
-		if chain.ID == chainID {
-			s.local[name] = append(chains[:i], chains[i+1:]...)
-			found = true
-			return
-		}
-	}
-
-	return
-}
-
-func (s *inmemory) ListOverrides(name Name) []*Chain {
-	return s.local[name]
-}
diff --git a/inmemory_test.go b/inmemory_test.go
deleted file mode 100644
index b5be336..0000000
--- a/inmemory_test.go
+++ /dev/null
@@ -1,193 +0,0 @@
-package policyengine
-
-import (
-	"testing"
-
-	"github.com/stretchr/testify/require"
-)
-
-func TestInmemory(t *testing.T) {
-	const (
-		object     = "native::object::abc/xyz"
-		container  = "native::object::abc/*"
-		namespace  = "Tenant1"
-		namespace2 = "Tenant2"
-		actor1     = "owner1"
-		actor2     = "owner2"
-	)
-
-	s := NewInMemory()
-
-	// Object which was put via S3.
-	res := newResource(object, map[string]string{"FromS3": "true"})
-	// Request initiating from the trusted subnet and actor.
-	reqGood := newRequest("native::object::put", res, map[string]string{
-		"SourceIP": "10.1.1.12",
-		"Actor":    actor1,
-	})
-
-	status, ok := s.IsAllowed(Ingress, namespace, reqGood)
-	require.Equal(t, NoRuleFound, status)
-	require.False(t, ok)
-
-	s.AddNameSpaceChain(Ingress, namespace, &Chain{
-		Rules: []Rule{
-			{ // Restrict to remove ANY object from the namespace.
-				Status:    AccessDenied,
-				Actions:   Actions{Names: []string{"native::object::delete"}},
-				Resources: Resources{Names: []string{"native::object::*"}},
-			},
-			{ // Allow to put object only from the trusted subnet AND trusted actor, deny otherwise.
-				Status:    AccessDenied,
-				Actions:   Actions{Names: []string{"native::object::put"}},
-				Resources: Resources{Names: []string{"native::object::*"}},
-				Any:       true,
-				Condition: []Condition{
-					{
-						Op:     CondStringNotLike,
-						Object: ObjectRequest,
-						Key:    "SourceIP",
-						Value:  "10.1.1.*",
-					},
-					{
-						Op:     CondStringNotEquals,
-						Object: ObjectRequest,
-						Key:    "Actor",
-						Value:  actor1,
-					},
-				},
-			},
-		},
-	})
-
-	s.AddNameSpaceChain(Ingress, namespace2, &Chain{
-		Rules: []Rule{
-			{ // Deny all expect "native::object::get" for all objects expect "native::object::abc/xyz".
-				Status:    AccessDenied,
-				Actions:   Actions{Inverted: true, Names: []string{"native::object::get"}},
-				Resources: Resources{Inverted: true, Names: []string{object}},
-			},
-		},
-	})
-
-	s.AddResourceChain(Ingress, container, &Chain{
-		Rules: []Rule{
-			{ // Allow to actor2 to get objects from the specific container only if they have `Department=HR` attribute.
-				Status:    Allow,
-				Actions:   Actions{Names: []string{"native::object::get"}},
-				Resources: Resources{Names: []string{"native::object::abc/*"}},
-				Condition: []Condition{
-					{
-						Op:     CondStringEquals,
-						Object: ObjectResource,
-						Key:    "Department",
-						Value:  "HR",
-					},
-					{
-						Op:     CondStringEquals,
-						Object: ObjectRequest,
-						Key:    "Actor",
-						Value:  actor2,
-					},
-				},
-			},
-		},
-	})
-
-	t.Run("bad subnet, namespace deny", func(t *testing.T) {
-		// Request initiating from the untrusted subnet.
-		reqBadIP := newRequest("native::object::put", res, map[string]string{
-			"SourceIP": "10.122.1.20",
-			"Actor":    actor1,
-		})
-		status, ok := s.IsAllowed(Ingress, namespace, reqBadIP)
-		require.Equal(t, AccessDenied, status)
-		require.True(t, ok)
-	})
-	t.Run("bad actor, namespace deny", func(t *testing.T) {
-		// Request initiating from the untrusted actor.
-		reqBadActor := newRequest("native::object::put", res, map[string]string{
-			"SourceIP": "10.1.1.13",
-			"Actor":    actor2,
-		})
-		status, ok := s.IsAllowed(Ingress, namespace, reqBadActor)
-		require.Equal(t, AccessDenied, status)
-		require.True(t, ok)
-	})
-	t.Run("bad object, container deny", func(t *testing.T) {
-		objGood := newResource("native::object::abc/id1", map[string]string{"Department": "HR"})
-		objBadAttr := newResource("native::object::abc/id2", map[string]string{"Department": "Support"})
-
-		status, ok := s.IsAllowed(Ingress, namespace, newRequest("native::object::get", objGood, map[string]string{
-			"SourceIP": "10.1.1.14",
-			"Actor":    actor2,
-		}))
-		require.Equal(t, Allow, status)
-		require.True(t, ok)
-
-		status, ok = s.IsAllowed(Ingress, namespace, newRequest("native::object::get", objBadAttr, map[string]string{
-			"SourceIP": "10.1.1.14",
-			"Actor":    actor2,
-		}))
-		require.Equal(t, NoRuleFound, status)
-		require.False(t, ok)
-	})
-	t.Run("bad operation, namespace deny", func(t *testing.T) {
-		// Request with the forbidden operation.
-		reqBadOperation := newRequest("native::object::delete", res, map[string]string{
-			"SourceIP": "10.1.1.12",
-			"Actor":    actor1,
-		})
-		status, ok := s.IsAllowed(Ingress, namespace, reqBadOperation)
-		require.Equal(t, AccessDenied, status)
-		require.True(t, ok)
-	})
-	t.Run("inverted rules", func(t *testing.T) {
-		req := newRequest("native::object::put", newResource(object, nil), nil)
-		status, ok = s.IsAllowed(Ingress, namespace2, req)
-		require.Equal(t, NoRuleFound, status)
-		require.False(t, ok)
-
-		req = newRequest("native::object::put", newResource("native::object::cba/def", nil), nil)
-		status, ok = s.IsAllowed(Ingress, namespace2, req)
-		require.Equal(t, AccessDenied, status)
-		require.True(t, ok)
-
-		req = newRequest("native::object::get", newResource("native::object::cba/def", nil), nil)
-		status, ok = s.IsAllowed(Ingress, namespace2, req)
-		require.Equal(t, NoRuleFound, status)
-		require.False(t, ok)
-	})
-	t.Run("good", func(t *testing.T) {
-		status, ok = s.IsAllowed(Ingress, namespace, reqGood)
-		require.Equal(t, NoRuleFound, status)
-		require.False(t, ok)
-
-		t.Run("quota on a different container", func(t *testing.T) {
-			s.AddOverride(Ingress, &Chain{
-				Rules: []Rule{{
-					Status:    QuotaLimitReached,
-					Actions:   Actions{Names: []string{"native::object::put"}},
-					Resources: Resources{Names: []string{"native::object::cba/*"}},
-				}},
-			})
-
-			status, ok = s.IsAllowed(Ingress, namespace, reqGood)
-			require.Equal(t, NoRuleFound, status)
-			require.False(t, ok)
-		})
-		t.Run("quota on the request container", func(t *testing.T) {
-			s.AddOverride(Ingress, &Chain{
-				Rules: []Rule{{
-					Status:    QuotaLimitReached,
-					Actions:   Actions{Names: []string{"native::object::put"}},
-					Resources: Resources{Names: []string{"native::object::abc/*"}},
-				}},
-			})
-
-			status, ok = s.IsAllowed(Ingress, namespace, reqGood)
-			require.Equal(t, QuotaLimitReached, status)
-			require.True(t, ok)
-		})
-	})
-}
diff --git a/interface.go b/interface.go
deleted file mode 100644
index d75a701..0000000
--- a/interface.go
+++ /dev/null
@@ -1,18 +0,0 @@
-package policyengine
-
-// CachedChainStorage ...
-type CachedChainStorage interface {
-	Engine
-	// Adds a policy chain used for all operations with a specific resource.
-	AddResourceChain(name Name, resource string, c *Chain)
-	// Adds a policy chain used for all operations in the namespace.
-	AddNameSpaceChain(name Name, namespace string, c *Chain)
-	// Adds a local policy chain used for all operations with this service.
-	AddOverride(name Name, c *Chain)
-	// Gets the local override with given chain id.
-	GetOverride(name Name, chainID ChainID) (chain *Chain, found bool)
-	// Remove the local override with given chain id.
-	RemoveOverride(name Name, chainID ChainID) (removed bool)
-	// ListOverrides returns the list of local overrides.
-	ListOverrides(name Name) []*Chain
-}
diff --git a/chain.go b/pkg/chain/chain.go
similarity index 86%
rename from chain.go
rename to pkg/chain/chain.go
index cb17f70..a98ef43 100644
--- a/chain.go
+++ b/pkg/chain/chain.go
@@ -1,25 +1,19 @@
-package policyengine
+package chain
 
 import (
 	"encoding/json"
 	"fmt"
 	"strings"
 
+	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/resource"
 	"git.frostfs.info/TrueCloudLab/policy-engine/util"
 )
 
-// Engine ...
-type Engine interface {
-	// IsAllowed returns status for the operation after all checks.
-	// The second return value signifies whether a matching rule was found.
-	IsAllowed(name Name, namespace string, r Request) (Status, bool)
-}
-
-// ChainID is the ID of rule chain.
-type ChainID string
+// ID is the ID of rule chain.
+type ID string
 
 type Chain struct {
-	ID ChainID
+	ID ID
 
 	Rules []Rule
 }
@@ -138,7 +132,7 @@ func (c ConditionType) String() string {
 	}
 }
 
-func (c *Condition) Match(req Request) bool {
+func (c *Condition) Match(req resource.Request) bool {
 	var val string
 	switch c.Object {
 	case ObjectResource:
@@ -175,7 +169,7 @@ func (c *Condition) Match(req Request) bool {
 	}
 }
 
-func (r *Rule) Match(req Request) (status Status, matched bool) {
+func (r *Rule) Match(req resource.Request) (status Status, matched bool) {
 	found := len(r.Resources.Names) == 0
 	for i := range r.Resources.Names {
 		if util.GlobMatch(req.Resource().Name(), r.Resources.Names[i]) != r.Resources.Inverted {
@@ -194,14 +188,14 @@ func (r *Rule) Match(req Request) (status Status, matched bool) {
 	return NoRuleFound, false
 }
 
-func (r *Rule) matchCondition(obj Request) (status Status, matched bool) {
+func (r *Rule) matchCondition(obj resource.Request) (status Status, matched bool) {
 	if r.Any {
 		return r.matchAny(obj)
 	}
 	return r.matchAll(obj)
 }
 
-func (r *Rule) matchAny(obj Request) (status Status, matched bool) {
+func (r *Rule) matchAny(obj resource.Request) (status Status, matched bool) {
 	for i := range r.Condition {
 		if r.Condition[i].Match(obj) {
 			return r.Status, true
@@ -210,7 +204,7 @@ func (r *Rule) matchAny(obj Request) (status Status, matched bool) {
 	return NoRuleFound, false
 }
 
-func (r *Rule) matchAll(obj Request) (status Status, matched bool) {
+func (r *Rule) matchAll(obj resource.Request) (status Status, matched bool) {
 	for i := range r.Condition {
 		if !r.Condition[i].Match(obj) {
 			return NoRuleFound, false
@@ -219,7 +213,7 @@ func (r *Rule) matchAll(obj Request) (status Status, matched bool) {
 	return r.Status, true
 }
 
-func (c *Chain) Match(req Request) (status Status, matched bool) {
+func (c *Chain) Match(req resource.Request) (status Status, matched bool) {
 	for i := range c.Rules {
 		status, matched := c.Rules[i].Match(req)
 		if matched {
diff --git a/chain_names.go b/pkg/chain/chain_names.go
similarity index 92%
rename from chain_names.go
rename to pkg/chain/chain_names.go
index 637b967..8bb88c0 100644
--- a/chain_names.go
+++ b/pkg/chain/chain_names.go
@@ -1,4 +1,4 @@
-package policyengine
+package chain
 
 // Name represents the place in the request lifecycle where policy is applied.
 type Name string
diff --git a/chain_test.go b/pkg/chain/chain_test.go
similarity index 96%
rename from chain_test.go
rename to pkg/chain/chain_test.go
index 690ec37..2c5ae9c 100644
--- a/chain_test.go
+++ b/pkg/chain/chain_test.go
@@ -1,4 +1,4 @@
-package policyengine
+package chain
 
 import (
 	"testing"
diff --git a/error.go b/pkg/chain/error.go
similarity index 96%
rename from error.go
rename to pkg/chain/error.go
index 3fc1c59..218e372 100644
--- a/error.go
+++ b/pkg/chain/error.go
@@ -1,4 +1,4 @@
-package policyengine
+package chain
 
 import "fmt"
 
diff --git a/pkg/engine/inmemory.go b/pkg/engine/inmemory.go
new file mode 100644
index 0000000..c37fdd9
--- /dev/null
+++ b/pkg/engine/inmemory.go
@@ -0,0 +1,113 @@
+package engine
+
+import (
+	"git.frostfs.info/TrueCloudLab/policy-engine/util"
+
+	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/chain"
+	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/resource"
+)
+
+type inmemory struct {
+	namespace map[chain.Name][]chainWrapper
+	resource  map[chain.Name][]chainWrapper
+	local     map[chain.Name][]*chain.Chain
+}
+
+type chainWrapper struct {
+	object string
+	chain  *chain.Chain
+}
+
+// NewInMemory returns new inmemory instance of chain storage.
+func NewInMemory() CachedChainStorage {
+	return &inmemory{
+		namespace: make(map[chain.Name][]chainWrapper),
+		resource:  make(map[chain.Name][]chainWrapper),
+		local:     make(map[chain.Name][]*chain.Chain),
+	}
+}
+
+// IsAllowed implements the Engine interface.
+func (s *inmemory) IsAllowed(name chain.Name, namespace string, r resource.Request) (chain.Status, bool) {
+	var ruleFound bool
+	if local, ok := s.local[name]; ok {
+		for _, c := range local {
+			if status, matched := c.Match(r); matched && status != chain.Allow {
+				return status, true
+			}
+		}
+	}
+	if cs, ok := s.namespace[name]; ok {
+		status, ok := matchArray(cs, namespace, r)
+		if ok && status != chain.Allow {
+			return status, true
+		}
+		ruleFound = ruleFound || ok
+	}
+	if cs, ok := s.resource[name]; ok {
+		status, ok := matchArray(cs, r.Resource().Name(), r)
+		if ok {
+			return status, true
+		}
+		ruleFound = ruleFound || ok
+	}
+	if ruleFound {
+		return chain.Allow, true
+	}
+	return chain.NoRuleFound, false
+}
+
+func matchArray(cs []chainWrapper, object string, r resource.Request) (chain.Status, bool) {
+	for _, c := range cs {
+		if !util.GlobMatch(object, c.object) {
+			continue
+		}
+		if status, matched := c.chain.Match(r); matched {
+			return status, true
+		}
+	}
+	return chain.NoRuleFound, false
+}
+
+func (s *inmemory) AddResourceChain(name chain.Name, resource string, c *chain.Chain) {
+	s.resource[name] = append(s.resource[name], chainWrapper{resource, c})
+}
+
+func (s *inmemory) AddNameSpaceChain(name chain.Name, namespace string, c *chain.Chain) {
+	s.namespace[name] = append(s.namespace[name], chainWrapper{namespace, c})
+}
+
+func (s *inmemory) AddOverride(name chain.Name, c *chain.Chain) {
+	s.local[name] = append(s.local[name], c)
+}
+
+func (s *inmemory) GetOverride(name chain.Name, chainID chain.ID) (chain *chain.Chain, found bool) {
+	chains := s.local[name]
+
+	for _, chain = range chains {
+		if chain.ID == chainID {
+			found = true
+			return
+		}
+	}
+
+	return
+}
+
+func (s *inmemory) RemoveOverride(name chain.Name, chainID chain.ID) (found bool) {
+	chains := s.local[name]
+
+	for i, chain := range chains {
+		if chain.ID == chainID {
+			s.local[name] = append(chains[:i], chains[i+1:]...)
+			found = true
+			return
+		}
+	}
+
+	return
+}
+
+func (s *inmemory) ListOverrides(name chain.Name) []*chain.Chain {
+	return s.local[name]
+}
diff --git a/pkg/engine/inmemory_test.go b/pkg/engine/inmemory_test.go
new file mode 100644
index 0000000..72e7fc0
--- /dev/null
+++ b/pkg/engine/inmemory_test.go
@@ -0,0 +1,195 @@
+package engine
+
+import (
+	"testing"
+
+	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/chain"
+	resourcetest "git.frostfs.info/TrueCloudLab/policy-engine/pkg/resource/testutil"
+	"github.com/stretchr/testify/require"
+)
+
+func TestInmemory(t *testing.T) {
+	const (
+		object     = "native::object::abc/xyz"
+		container  = "native::object::abc/*"
+		namespace  = "Tenant1"
+		namespace2 = "Tenant2"
+		actor1     = "owner1"
+		actor2     = "owner2"
+	)
+
+	s := NewInMemory()
+
+	// Object which was put via S3.
+	res := resourcetest.NewResource(object, map[string]string{"FromS3": "true"})
+	// Request initiating from the trusted subnet and actor.
+	reqGood := resourcetest.NewRequest("native::object::put", res, map[string]string{
+		"SourceIP": "10.1.1.12",
+		"Actor":    actor1,
+	})
+
+	status, ok := s.IsAllowed(chain.Ingress, namespace, reqGood)
+	require.Equal(t, chain.NoRuleFound, status)
+	require.False(t, ok)
+
+	s.AddNameSpaceChain(chain.Ingress, namespace, &chain.Chain{
+		Rules: []chain.Rule{
+			{ // Restrict to remove ANY object from the namespace.
+				Status:    chain.AccessDenied,
+				Actions:   chain.Actions{Names: []string{"native::object::delete"}},
+				Resources: chain.Resources{Names: []string{"native::object::*"}},
+			},
+			{ // Allow to put object only from the trusted subnet AND trusted actor, deny otherwise.
+				Status:    chain.AccessDenied,
+				Actions:   chain.Actions{Names: []string{"native::object::put"}},
+				Resources: chain.Resources{Names: []string{"native::object::*"}},
+				Any:       true,
+				Condition: []chain.Condition{
+					{
+						Op:     chain.CondStringNotLike,
+						Object: chain.ObjectRequest,
+						Key:    "SourceIP",
+						Value:  "10.1.1.*",
+					},
+					{
+						Op:     chain.CondStringNotEquals,
+						Object: chain.ObjectRequest,
+						Key:    "Actor",
+						Value:  actor1,
+					},
+				},
+			},
+		},
+	})
+
+	s.AddNameSpaceChain(chain.Ingress, namespace2, &chain.Chain{
+		Rules: []chain.Rule{
+			{ // Deny all expect "native::object::get" for all objects expect "native::object::abc/xyz".
+				Status:    chain.AccessDenied,
+				Actions:   chain.Actions{Inverted: true, Names: []string{"native::object::get"}},
+				Resources: chain.Resources{Inverted: true, Names: []string{object}},
+			},
+		},
+	})
+
+	s.AddResourceChain(chain.Ingress, container, &chain.Chain{
+		Rules: []chain.Rule{
+			{ // Allow to actor2 to get objects from the specific container only if they have `Department=HR` attribute.
+				Status:    chain.Allow,
+				Actions:   chain.Actions{Names: []string{"native::object::get"}},
+				Resources: chain.Resources{Names: []string{"native::object::abc/*"}},
+				Condition: []chain.Condition{
+					{
+						Op:     chain.CondStringEquals,
+						Object: chain.ObjectResource,
+						Key:    "Department",
+						Value:  "HR",
+					},
+					{
+						Op:     chain.CondStringEquals,
+						Object: chain.ObjectRequest,
+						Key:    "Actor",
+						Value:  actor2,
+					},
+				},
+			},
+		},
+	})
+
+	t.Run("bad subnet, namespace deny", func(t *testing.T) {
+		// Request initiating from the untrusted subnet.
+		reqBadIP := resourcetest.NewRequest("native::object::put", res, map[string]string{
+			"SourceIP": "10.122.1.20",
+			"Actor":    actor1,
+		})
+		status, ok := s.IsAllowed(chain.Ingress, namespace, reqBadIP)
+		require.Equal(t, chain.AccessDenied, status)
+		require.True(t, ok)
+	})
+	t.Run("bad actor, namespace deny", func(t *testing.T) {
+		// Request initiating from the untrusted actor.
+		reqBadActor := resourcetest.NewRequest("native::object::put", res, map[string]string{
+			"SourceIP": "10.1.1.13",
+			"Actor":    actor2,
+		})
+		status, ok := s.IsAllowed(chain.Ingress, namespace, reqBadActor)
+		require.Equal(t, chain.AccessDenied, status)
+		require.True(t, ok)
+	})
+	t.Run("bad object, container deny", func(t *testing.T) {
+		objGood := resourcetest.NewResource("native::object::abc/id1", map[string]string{"Department": "HR"})
+		objBadAttr := resourcetest.NewResource("native::object::abc/id2", map[string]string{"Department": "Support"})
+
+		status, ok := s.IsAllowed(chain.Ingress, namespace, resourcetest.NewRequest("native::object::get", objGood, map[string]string{
+			"SourceIP": "10.1.1.14",
+			"Actor":    actor2,
+		}))
+		require.Equal(t, chain.Allow, status)
+		require.True(t, ok)
+
+		status, ok = s.IsAllowed(chain.Ingress, namespace, resourcetest.NewRequest("native::object::get", objBadAttr, map[string]string{
+			"SourceIP": "10.1.1.14",
+			"Actor":    actor2,
+		}))
+		require.Equal(t, chain.NoRuleFound, status)
+		require.False(t, ok)
+	})
+	t.Run("bad operation, namespace deny", func(t *testing.T) {
+		// Request with the forbidden operation.
+		reqBadOperation := resourcetest.NewRequest("native::object::delete", res, map[string]string{
+			"SourceIP": "10.1.1.12",
+			"Actor":    actor1,
+		})
+		status, ok := s.IsAllowed(chain.Ingress, namespace, reqBadOperation)
+		require.Equal(t, chain.AccessDenied, status)
+		require.True(t, ok)
+	})
+	t.Run("inverted rules", func(t *testing.T) {
+		req := resourcetest.NewRequest("native::object::put", resourcetest.NewResource(object, nil), nil)
+		status, ok = s.IsAllowed(chain.Ingress, namespace2, req)
+		require.Equal(t, chain.NoRuleFound, status)
+		require.False(t, ok)
+
+		req = resourcetest.NewRequest("native::object::put", resourcetest.NewResource("native::object::cba/def", nil), nil)
+		status, ok = s.IsAllowed(chain.Ingress, namespace2, req)
+		require.Equal(t, chain.AccessDenied, status)
+		require.True(t, ok)
+
+		req = resourcetest.NewRequest("native::object::get", resourcetest.NewResource("native::object::cba/def", nil), nil)
+		status, ok = s.IsAllowed(chain.Ingress, namespace2, req)
+		require.Equal(t, chain.NoRuleFound, status)
+		require.False(t, ok)
+	})
+	t.Run("good", func(t *testing.T) {
+		status, ok = s.IsAllowed(chain.Ingress, namespace, reqGood)
+		require.Equal(t, chain.NoRuleFound, status)
+		require.False(t, ok)
+
+		t.Run("quota on a different container", func(t *testing.T) {
+			s.AddOverride(chain.Ingress, &chain.Chain{
+				Rules: []chain.Rule{{
+					Status:    chain.QuotaLimitReached,
+					Actions:   chain.Actions{Names: []string{"native::object::put"}},
+					Resources: chain.Resources{Names: []string{"native::object::cba/*"}},
+				}},
+			})
+
+			status, ok = s.IsAllowed(chain.Ingress, namespace, reqGood)
+			require.Equal(t, chain.NoRuleFound, status)
+			require.False(t, ok)
+		})
+		t.Run("quota on the request container", func(t *testing.T) {
+			s.AddOverride(chain.Ingress, &chain.Chain{
+				Rules: []chain.Rule{{
+					Status:    chain.QuotaLimitReached,
+					Actions:   chain.Actions{Names: []string{"native::object::put"}},
+					Resources: chain.Resources{Names: []string{"native::object::abc/*"}},
+				}},
+			})
+
+			status, ok = s.IsAllowed(chain.Ingress, namespace, reqGood)
+			require.Equal(t, chain.QuotaLimitReached, status)
+			require.True(t, ok)
+		})
+	})
+}
diff --git a/pkg/engine/interface.go b/pkg/engine/interface.go
new file mode 100644
index 0000000..e753951
--- /dev/null
+++ b/pkg/engine/interface.go
@@ -0,0 +1,30 @@
+package engine
+
+import (
+	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/chain"
+	"git.frostfs.info/TrueCloudLab/policy-engine/pkg/resource"
+)
+
+// Engine ...
+type Engine interface {
+	// IsAllowed returns status for the operation after all checks.
+	// The second return value signifies whether a matching rule was found.
+	IsAllowed(name chain.Name, namespace string, r resource.Request) (chain.Status, bool)
+}
+
+// CachedChainStorage ...
+type CachedChainStorage interface {
+	Engine
+	// Adds a policy chain used for all operations with a specific resource.
+	AddResourceChain(name chain.Name, resource string, c *chain.Chain)
+	// Adds a policy chain used for all operations in the namespace.
+	AddNameSpaceChain(name chain.Name, namespace string, c *chain.Chain)
+	// Adds a local policy chain used for all operations with this service.
+	AddOverride(name chain.Name, c *chain.Chain)
+	// Gets the local override with given chain id.
+	GetOverride(name chain.Name, chainID chain.ID) (chain *chain.Chain, found bool)
+	// Remove the local override with given chain id.
+	RemoveOverride(name chain.Name, chainID chain.ID) (removed bool)
+	// ListOverrides returns the list of local overrides.
+	ListOverrides(name chain.Name) []*chain.Chain
+}
diff --git a/resource.go b/pkg/resource/resource.go
similarity index 96%
rename from resource.go
rename to pkg/resource/resource.go
index 94187cd..7180f20 100644
--- a/resource.go
+++ b/pkg/resource/resource.go
@@ -1,4 +1,4 @@
-package policyengine
+package resource
 
 // Request represents generic named resource (bucket, container etc.).
 // Name is resource depenent but should be globally unique for any given
diff --git a/pkg/resource/testutil/resource.go b/pkg/resource/testutil/resource.go
new file mode 100644
index 0000000..02e6394
--- /dev/null
+++ b/pkg/resource/testutil/resource.go
@@ -0,0 +1,53 @@
+package testutil
+
+import (
+	resourcepkg "git.frostfs.info/TrueCloudLab/policy-engine/pkg/resource"
+)
+
+type Resource struct {
+	name       string
+	properties map[string]string
+}
+
+func (r *Resource) Name() string {
+	return r.name
+}
+
+func (r *Resource) Property(name string) string {
+	return r.properties[name]
+}
+
+func NewResource(name string, properties map[string]string) *Resource {
+	if properties == nil {
+		properties = make(map[string]string)
+	}
+	return &Resource{name: name, properties: properties}
+}
+
+type Request struct {
+	operation  string
+	properties map[string]string
+	resource   *Resource
+}
+
+var _ resourcepkg.Request = (*Request)(nil)
+
+func (r *Request) Operation() string {
+	return r.operation
+}
+
+func (r *Request) Resource() resourcepkg.Resource {
+	return r.resource
+}
+
+func (r *Request) Property(name string) string {
+	return r.properties[name]
+}
+
+func NewRequest(op string, r *Resource, properties map[string]string) *Request {
+	return &Request{
+		operation:  op,
+		properties: properties,
+		resource:   r,
+	}
+}
diff --git a/resource_test.go b/resource_test.go
deleted file mode 100644
index ed68e3a..0000000
--- a/resource_test.go
+++ /dev/null
@@ -1,49 +0,0 @@
-package policyengine
-
-type resource struct {
-	name       string
-	properties map[string]string
-}
-
-func (r *resource) Name() string {
-	return r.name
-}
-
-func (r *resource) Property(name string) string {
-	return r.properties[name]
-}
-
-func newResource(name string, properties map[string]string) *resource {
-	if properties == nil {
-		properties = make(map[string]string)
-	}
-	return &resource{name: name, properties: properties}
-}
-
-type request struct {
-	operation  string
-	properties map[string]string
-	resource   *resource
-}
-
-var _ Request = (*request)(nil)
-
-func (r *request) Operation() string {
-	return r.operation
-}
-
-func (r *request) Resource() Resource {
-	return r.resource
-}
-
-func (r *request) Property(name string) string {
-	return r.properties[name]
-}
-
-func newRequest(op string, r *resource, properties map[string]string) *request {
-	return &request{
-		operation:  op,
-		properties: properties,
-		resource:   r,
-	}
-}