diff --git a/archiver.go b/archiver.go
index 558b39524..983d6f168 100644
--- a/archiver.go
+++ b/archiver.go
@@ -15,6 +15,7 @@ import (
 	"github.com/restic/restic/chunker"
 	"github.com/restic/restic/debug"
 	"github.com/restic/restic/pipe"
+	"github.com/restic/restic/server"
 )
 
 const (
@@ -27,7 +28,7 @@ const (
 )
 
 type Archiver struct {
-	s Server
+	s *server.Server
 	m *Map
 	c *Cache
 
@@ -37,7 +38,7 @@ type Archiver struct {
 	Filter func(item string, fi os.FileInfo) bool
 }
 
-func NewArchiver(s Server) (*Archiver, error) {
+func NewArchiver(s *server.Server) (*Archiver, error) {
 	var err error
 	arch := &Archiver{
 		s:         s,
@@ -101,7 +102,7 @@ func (arch *Archiver) Preload() error {
 	return nil
 }
 
-func (arch *Archiver) Save(t backend.Type, id backend.ID, length uint, rd io.Reader) (Blob, error) {
+func (arch *Archiver) Save(t backend.Type, id backend.ID, length uint, rd io.Reader) (server.Blob, error) {
 	debug.Log("Archiver.Save", "Save(%v, %v)\n", t, id.Str())
 
 	// test if this blob is already known
@@ -127,7 +128,7 @@ func (arch *Archiver) Save(t backend.Type, id backend.ID, length uint, rd io.Rea
 		// TODO: implement a list of blobs in transport, so this doesn't happen so often
 		err = arch.s.Remove(t, blob.Storage.String())
 		if err != nil {
-			return Blob{}, err
+			return server.Blob{}, err
 		}
 	}
 
@@ -136,13 +137,13 @@ func (arch *Archiver) Save(t backend.Type, id backend.ID, length uint, rd io.Rea
 	return smapblob, nil
 }
 
-func (arch *Archiver) SaveTreeJSON(item interface{}) (Blob, error) {
+func (arch *Archiver) SaveTreeJSON(item interface{}) (server.Blob, error) {
 	// convert to json
 	data, err := json.Marshal(item)
 	// append newline
 	data = append(data, '\n')
 	if err != nil {
-		return Blob{}, err
+		return server.Blob{}, err
 	}
 
 	// check if tree has been saved before
@@ -157,7 +158,7 @@ func (arch *Archiver) SaveTreeJSON(item interface{}) (Blob, error) {
 	// otherwise save the data
 	blob, err = arch.s.SaveJSON(backend.Tree, item)
 	if err != nil {
-		return Blob{}, err
+		return server.Blob{}, err
 	}
 
 	// store blob in storage map
@@ -168,7 +169,7 @@ func (arch *Archiver) SaveTreeJSON(item interface{}) (Blob, error) {
 
 // SaveFile stores the content of the file on the backend as a Blob by calling
 // Save for each chunk.
-func (arch *Archiver) SaveFile(p *Progress, node *Node) (Blobs, error) {
+func (arch *Archiver) SaveFile(p *Progress, node *Node) (server.Blobs, error) {
 	file, err := node.OpenForReading()
 	defer file.Close()
 	if err != nil {
@@ -197,12 +198,12 @@ func (arch *Archiver) SaveFile(p *Progress, node *Node) (Blobs, error) {
 		}
 	}
 
-	var blobs Blobs
+	var blobs server.Blobs
 
 	// store all chunks
 	chnker := GetChunker("archiver.SaveFile")
 	chnker.Reset(file, arch.s.ChunkerPolynomial())
-	chans := [](<-chan Blob){}
+	chans := [](<-chan server.Blob){}
 	defer FreeChunker("archiver.SaveFile", chnker)
 
 	chunks := 0
@@ -221,9 +222,9 @@ func (arch *Archiver) SaveFile(p *Progress, node *Node) (Blobs, error) {
 
 		// acquire token, start goroutine to save chunk
 		token := <-arch.blobToken
-		resCh := make(chan Blob, 1)
+		resCh := make(chan server.Blob, 1)
 
-		go func(ch chan<- Blob) {
+		go func(ch chan<- server.Blob) {
 			blob, err := arch.Save(backend.Data, chunk.Digest, chunk.Length, chunk.Reader(file))
 			// TODO handle error
 			if err != nil {
@@ -238,7 +239,7 @@ func (arch *Archiver) SaveFile(p *Progress, node *Node) (Blobs, error) {
 		chans = append(chans, resCh)
 	}
 
-	blobs = []Blob{}
+	blobs = []server.Blob{}
 	for _, ch := range chans {
 		blobs = append(blobs, <-ch)
 	}
@@ -267,7 +268,7 @@ func (arch *Archiver) SaveFile(p *Progress, node *Node) (Blobs, error) {
 	return blobs, nil
 }
 
-func (arch *Archiver) saveTree(p *Progress, t *Tree) (Blob, error) {
+func (arch *Archiver) saveTree(p *Progress, t *Tree) (server.Blob, error) {
 	debug.Log("Archiver.saveTree", "saveTree(%v)\n", t)
 	var wg sync.WaitGroup
 
@@ -279,7 +280,7 @@ func (arch *Archiver) saveTree(p *Progress, t *Tree) (Blob, error) {
 		if node.tree != nil {
 			b, err := arch.saveTree(p, node.tree)
 			if err != nil {
-				return Blob{}, err
+				return server.Blob{}, err
 			}
 			node.Subtree = b.ID
 			t.Map.Insert(b)
@@ -321,7 +322,7 @@ func (arch *Archiver) saveTree(p *Progress, t *Tree) (Blob, error) {
 				go func(n *Node) {
 					defer wg.Done()
 
-					var blobs Blobs
+					var blobs server.Blobs
 					blobs, n.err = arch.SaveFile(p, n)
 					for _, b := range blobs {
 						t.Map.Insert(b)
@@ -340,7 +341,7 @@ func (arch *Archiver) saveTree(p *Progress, t *Tree) (Blob, error) {
 	// check for invalid file nodes
 	for _, node := range t.Nodes {
 		if node.Type == "file" && node.Content == nil && node.err == nil {
-			return Blob{}, fmt.Errorf("node %v has empty content", node.Name)
+			return server.Blob{}, fmt.Errorf("node %v has empty content", node.Name)
 		}
 
 		// remember used hashes
@@ -357,7 +358,7 @@ func (arch *Archiver) saveTree(p *Progress, t *Tree) (Blob, error) {
 		if node.err != nil {
 			err := arch.Error(node.path, nil, node.err)
 			if err != nil {
-				return Blob{}, err
+				return server.Blob{}, err
 			}
 
 			// save error message in node
@@ -375,7 +376,7 @@ func (arch *Archiver) saveTree(p *Progress, t *Tree) (Blob, error) {
 
 	blob, err := arch.SaveTreeJSON(t)
 	if err != nil {
-		return Blob{}, err
+		return server.Blob{}, err
 	}
 
 	return blob, nil
@@ -531,7 +532,7 @@ func (arch *Archiver) dirWorker(wg *sync.WaitGroup, p *Progress, done <-chan str
 			debug.Log("Archiver.dirWorker", "save tree for %s: %v", dir.Path(), blob)
 
 			node.Subtree = blob.ID
-			node.blobs = Blobs{blob}
+			node.blobs = server.Blobs{blob}
 
 			dir.Result() <- node
 			if dir.Path() != "" {
diff --git a/archiver_test.go b/archiver_test.go
index 7e13a556a..77e10f17f 100644
--- a/archiver_test.go
+++ b/archiver_test.go
@@ -9,6 +9,7 @@ import (
 	"github.com/restic/restic"
 	"github.com/restic/restic/backend"
 	"github.com/restic/restic/chunker"
+	"github.com/restic/restic/server"
 	. "github.com/restic/restic/test"
 )
 
@@ -22,7 +23,7 @@ type Rdr interface {
 	io.ReaderAt
 }
 
-func benchmarkChunkEncrypt(b testing.TB, buf, buf2 []byte, rd Rdr, key *restic.Key) {
+func benchmarkChunkEncrypt(b testing.TB, buf, buf2 []byte, rd Rdr, key *server.Key) {
 	ch := restic.GetChunker("BenchmarkChunkEncrypt")
 	rd.Seek(0, 0)
 	ch.Reset(rd, testPol)
@@ -53,9 +54,9 @@ func BenchmarkChunkEncrypt(b *testing.B) {
 	data := Random(23, 10<<20) // 10MiB
 	rd := bytes.NewReader(data)
 
-	be := setupBackend(b)
-	defer teardownBackend(b, be)
-	key := setupKey(b, be, "geheim")
+	be := SetupBackend(b)
+	defer TeardownBackend(b, be)
+	key := SetupKey(b, be, "geheim")
 
 	buf := restic.GetChunkBuf("BenchmarkChunkEncrypt")
 	buf2 := restic.GetChunkBuf("BenchmarkChunkEncrypt")
@@ -71,7 +72,7 @@ func BenchmarkChunkEncrypt(b *testing.B) {
 	restic.FreeChunkBuf("BenchmarkChunkEncrypt", buf2)
 }
 
-func benchmarkChunkEncryptP(b *testing.PB, buf []byte, rd Rdr, key *restic.Key) {
+func benchmarkChunkEncryptP(b *testing.PB, buf []byte, rd Rdr, key *server.Key) {
 	ch := restic.GetChunker("BenchmarkChunkEncryptP")
 	rd.Seek(0, 0)
 	ch.Reset(rd, testPol)
@@ -92,9 +93,9 @@ func benchmarkChunkEncryptP(b *testing.PB, buf []byte, rd Rdr, key *restic.Key)
 }
 
 func BenchmarkChunkEncryptParallel(b *testing.B) {
-	be := setupBackend(b)
-	defer teardownBackend(b, be)
-	key := setupKey(b, be, "geheim")
+	be := SetupBackend(b)
+	defer TeardownBackend(b, be)
+	key := SetupKey(b, be, "geheim")
 
 	data := Random(23, 10<<20) // 10MiB
 
@@ -118,9 +119,9 @@ func BenchmarkArchiveDirectory(b *testing.B) {
 		b.Skip("benchdir not set, skipping BenchmarkArchiveDirectory")
 	}
 
-	server := setupBackend(b)
-	defer teardownBackend(b, server)
-	key := setupKey(b, server, "geheim")
+	server := SetupBackend(b)
+	defer TeardownBackend(b, server)
+	key := SetupKey(b, server, "geheim")
 	server.SetKey(key)
 
 	arch, err := restic.NewArchiver(server)
@@ -131,16 +132,7 @@ func BenchmarkArchiveDirectory(b *testing.B) {
 	b.Logf("snapshot archived as %v", id)
 }
 
-func snapshot(t testing.TB, server restic.Server, path string, parent backend.ID) *restic.Snapshot {
-	arch, err := restic.NewArchiver(server)
-	OK(t, err)
-	OK(t, arch.Preload())
-	sn, _, err := arch.Snapshot(nil, []string{path}, parent)
-	OK(t, err)
-	return sn
-}
-
-func countBlobs(t testing.TB, server restic.Server) (trees int, data int) {
+func countBlobs(t testing.TB, server *server.Server) (trees int, data int) {
 	return server.Count(backend.Tree), server.Count(backend.Data)
 }
 
@@ -149,13 +141,13 @@ func archiveWithPreload(t testing.TB) {
 		t.Skip("benchdir not set, skipping TestArchiverPreload")
 	}
 
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
+	server := SetupBackend(t)
+	defer TeardownBackend(t, server)
+	key := SetupKey(t, server, "geheim")
 	server.SetKey(key)
 
 	// archive a few files
-	sn := snapshot(t, server, *benchArchiveDirectory, nil)
+	sn := SnapshotDir(t, server, *benchArchiveDirectory, nil)
 	t.Logf("archived snapshot %v", sn.ID().Str())
 
 	// get archive stats
@@ -163,7 +155,7 @@ func archiveWithPreload(t testing.TB) {
 	t.Logf("found %v trees, %v data blobs", beforeTrees, beforeData)
 
 	// archive the same files again, without parent snapshot
-	sn2 := snapshot(t, server, *benchArchiveDirectory, nil)
+	sn2 := SnapshotDir(t, server, *benchArchiveDirectory, nil)
 	t.Logf("archived snapshot %v", sn2.ID().Str())
 
 	// get archive stats
@@ -177,7 +169,7 @@ func archiveWithPreload(t testing.TB) {
 	}
 
 	// archive the same files again, with a parent snapshot
-	sn3 := snapshot(t, server, *benchArchiveDirectory, sn2.ID())
+	sn3 := SnapshotDir(t, server, *benchArchiveDirectory, sn2.ID())
 	t.Logf("archived snapshot %v, parent %v", sn3.ID().Str(), sn2.ID().Str())
 
 	// get archive stats
@@ -200,9 +192,9 @@ func BenchmarkPreload(t *testing.B) {
 		t.Skip("benchdir not set, skipping TestArchiverPreload")
 	}
 
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
+	server := SetupBackend(t)
+	defer TeardownBackend(t, server)
+	key := SetupKey(t, server, "geheim")
 	server.SetKey(key)
 
 	// archive a few files
@@ -228,13 +220,13 @@ func BenchmarkLoadTree(t *testing.B) {
 		t.Skip("benchdir not set, skipping TestArchiverPreload")
 	}
 
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
-	server.SetKey(key)
+	s := SetupBackend(t)
+	defer TeardownBackend(t, s)
+	key := SetupKey(t, s, "geheim")
+	s.SetKey(key)
 
 	// archive a few files
-	arch, err := restic.NewArchiver(server)
+	arch, err := restic.NewArchiver(s)
 	OK(t, err)
 	sn, _, err := arch.Snapshot(nil, []string{*benchArchiveDirectory}, nil)
 	OK(t, err)
@@ -243,7 +235,7 @@ func BenchmarkLoadTree(t *testing.B) {
 	list := make([]backend.ID, 0, 10)
 	done := make(chan struct{})
 
-	for name := range server.List(backend.Tree, done) {
+	for name := range s.List(backend.Tree, done) {
 		id, err := backend.ParseID(name)
 		if err != nil {
 			t.Logf("invalid id for tree %v", name)
@@ -262,7 +254,7 @@ func BenchmarkLoadTree(t *testing.B) {
 
 	for i := 0; i < t.N; i++ {
 		for _, id := range list {
-			_, err := restic.LoadTree(server, restic.Blob{Storage: id})
+			_, err := restic.LoadTree(s, server.Blob{Storage: id})
 			OK(t, err)
 		}
 	}
diff --git a/cache.go b/cache.go
index 5de387df8..0d0a0c756 100644
--- a/cache.go
+++ b/cache.go
@@ -11,6 +11,7 @@ import (
 
 	"github.com/restic/restic/backend"
 	"github.com/restic/restic/debug"
+	"github.com/restic/restic/server"
 )
 
 type Cache struct {
@@ -106,7 +107,7 @@ func (c *Cache) Purge(t backend.Type, subtype string, id backend.ID) error {
 	return err
 }
 
-func (c *Cache) Clear(s Server) error {
+func (c *Cache) Clear(s *server.Server) error {
 	list, err := c.List(backend.Snapshot)
 	if err != nil {
 		return err
@@ -211,7 +212,7 @@ func (c *Cache) filename(t backend.Type, subtype string, id backend.ID) (string,
 
 // RefreshSnapshots loads the maps for all snapshots and saves them to the
 // local cache. Old cache entries are purged.
-func (c *Cache) RefreshSnapshots(s Server, p *Progress) error {
+func (c *Cache) RefreshSnapshots(s *server.Server, p *Progress) error {
 	defer p.Done()
 
 	// list cache entries
@@ -274,7 +275,7 @@ func (c *Cache) RefreshSnapshots(s Server, p *Progress) error {
 // cacheSnapshotBlobs creates a cache of all the blobs used within the
 // snapshot. It collects all blobs from all trees and saves the resulting map
 // to the cache and returns the map.
-func cacheSnapshotBlobs(p *Progress, s Server, c *Cache, id backend.ID) (*Map, error) {
+func cacheSnapshotBlobs(p *Progress, s *server.Server, c *Cache, id backend.ID) (*Map, error) {
 	debug.Log("CacheSnapshotBlobs", "create cache for snapshot %v", id.Str())
 
 	sn, err := LoadSnapshot(s, id)
@@ -338,7 +339,7 @@ func (c *Cache) StoreMap(snid backend.ID, m *Map) error {
 	return nil
 }
 
-func (c *Cache) LoadMap(s Server, snid backend.ID) (*Map, error) {
+func (c *Cache) LoadMap(s *server.Server, snid backend.ID) (*Map, error) {
 	rd, err := c.Load(backend.Snapshot, "blobs", snid)
 	if err != nil {
 		return nil, err
diff --git a/cache_test.go b/cache_test.go
index 878b1d0c3..98c8ff564 100644
--- a/cache_test.go
+++ b/cache_test.go
@@ -10,9 +10,9 @@ import (
 )
 
 func TestCache(t *testing.T) {
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
+	server := SetupBackend(t)
+	defer TeardownBackend(t, server)
+	key := SetupKey(t, server, "geheim")
 	server.SetKey(key)
 
 	cache, err := restic.NewCache(server)
diff --git a/cmd/restic/cmd_cat.go b/cmd/restic/cmd_cat.go
index 3a000233e..850ac4325 100644
--- a/cmd/restic/cmd_cat.go
+++ b/cmd/restic/cmd_cat.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/restic/restic"
 	"github.com/restic/restic/backend"
+	"github.com/restic/restic/server"
 )
 
 type CmdCat struct{}
@@ -112,7 +113,7 @@ func (cmd CmdCat) Execute(args []string) error {
 
 		dec := json.NewDecoder(rd)
 
-		var key restic.Key
+		var key server.Key
 		err = dec.Decode(&key)
 		if err != nil {
 			return err
diff --git a/cmd/restic/cmd_find.go b/cmd/restic/cmd_find.go
index ae18955dd..e80bda99f 100644
--- a/cmd/restic/cmd_find.go
+++ b/cmd/restic/cmd_find.go
@@ -8,6 +8,7 @@ import (
 	"github.com/restic/restic"
 	"github.com/restic/restic/backend"
 	"github.com/restic/restic/debug"
+	"github.com/restic/restic/server"
 )
 
 type findResult struct {
@@ -58,7 +59,7 @@ func parseTime(str string) (time.Time, error) {
 	return time.Time{}, fmt.Errorf("unable to parse time: %q", str)
 }
 
-func (c CmdFind) findInTree(s restic.Server, blob restic.Blob, path string) ([]findResult, error) {
+func (c CmdFind) findInTree(s *server.Server, blob server.Blob, path string) ([]findResult, error) {
 	debug.Log("restic.find", "checking tree %v\n", blob)
 	tree, err := restic.LoadTree(s, blob)
 	if err != nil {
@@ -109,7 +110,7 @@ func (c CmdFind) findInTree(s restic.Server, blob restic.Blob, path string) ([]f
 	return results, nil
 }
 
-func (c CmdFind) findInSnapshot(s restic.Server, name string) error {
+func (c CmdFind) findInSnapshot(s *server.Server, name string) error {
 	debug.Log("restic.find", "searching in snapshot %s\n  for entries within [%s %s]", name, c.oldest, c.newest)
 
 	id, err := backend.ParseID(name)
diff --git a/cmd/restic/cmd_fsck.go b/cmd/restic/cmd_fsck.go
index 0c0139189..2c360652e 100644
--- a/cmd/restic/cmd_fsck.go
+++ b/cmd/restic/cmd_fsck.go
@@ -8,6 +8,7 @@ import (
 	"github.com/restic/restic"
 	"github.com/restic/restic/backend"
 	"github.com/restic/restic/debug"
+	"github.com/restic/restic/server"
 )
 
 type CmdFsck struct {
@@ -31,7 +32,7 @@ func init() {
 	}
 }
 
-func fsckFile(opts CmdFsck, s restic.Server, m *restic.Map, IDs []backend.ID) (uint64, error) {
+func fsckFile(opts CmdFsck, s *server.Server, m *restic.Map, IDs []backend.ID) (uint64, error) {
 	debug.Log("restic.fsckFile", "checking file %v", IDs)
 	var bytes uint64
 
@@ -74,7 +75,7 @@ func fsckFile(opts CmdFsck, s restic.Server, m *restic.Map, IDs []backend.ID) (u
 	return bytes, nil
 }
 
-func fsckTree(opts CmdFsck, s restic.Server, blob restic.Blob) error {
+func fsckTree(opts CmdFsck, s *server.Server, blob server.Blob) error {
 	debug.Log("restic.fsckTree", "checking tree %v", blob)
 
 	tree, err := restic.LoadTree(s, blob)
@@ -161,7 +162,7 @@ func fsckTree(opts CmdFsck, s restic.Server, blob restic.Blob) error {
 	return firstErr
 }
 
-func fsckSnapshot(opts CmdFsck, s restic.Server, id backend.ID) error {
+func fsckSnapshot(opts CmdFsck, s *server.Server, id backend.ID) error {
 	debug.Log("restic.fsck", "checking snapshot %v\n", id)
 
 	sn, err := restic.LoadSnapshot(s, id)
diff --git a/cmd/restic/cmd_key.go b/cmd/restic/cmd_key.go
index 5afc3a8b3..9e87ff247 100644
--- a/cmd/restic/cmd_key.go
+++ b/cmd/restic/cmd_key.go
@@ -5,8 +5,8 @@ import (
 	"fmt"
 	"os"
 
-	"github.com/restic/restic"
 	"github.com/restic/restic/backend"
+	"github.com/restic/restic/server"
 )
 
 type CmdKey struct{}
@@ -21,7 +21,7 @@ func init() {
 	}
 }
 
-func listKeys(s restic.Server) error {
+func listKeys(s *server.Server) error {
 	tab := NewTable()
 	tab.Header = fmt.Sprintf(" %-10s  %-10s  %-10s  %s", "ID", "User", "Host", "Created")
 	tab.RowFormat = "%s%-10s  %-10s  %-10s  %s"
@@ -35,7 +35,7 @@ func listKeys(s restic.Server) error {
 	defer close(done)
 
 	for name := range s.List(backend.Key, done) {
-		k, err := restic.LoadKey(s, name)
+		k, err := server.LoadKey(s, name)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "LoadKey() failed: %v\n", err)
 			continue
@@ -56,7 +56,7 @@ func listKeys(s restic.Server) error {
 	return nil
 }
 
-func addKey(s restic.Server) error {
+func addKey(s *server.Server) error {
 	pw := readPassword("RESTIC_NEWPASSWORD", "enter password for new key: ")
 	pw2 := readPassword("RESTIC_NEWPASSWORD", "enter password again: ")
 
@@ -64,7 +64,7 @@ func addKey(s restic.Server) error {
 		return errors.New("passwords do not match")
 	}
 
-	id, err := restic.AddKey(s, pw, s.Key())
+	id, err := server.AddKey(s, pw, s.Key())
 	if err != nil {
 		return fmt.Errorf("creating new key failed: %v\n", err)
 	}
@@ -74,7 +74,7 @@ func addKey(s restic.Server) error {
 	return nil
 }
 
-func deleteKey(s restic.Server, name string) error {
+func deleteKey(s *server.Server, name string) error {
 	if name == s.Key().Name() {
 		return errors.New("refusing to remove key currently used to access repository")
 	}
@@ -88,7 +88,7 @@ func deleteKey(s restic.Server, name string) error {
 	return nil
 }
 
-func changePassword(s restic.Server) error {
+func changePassword(s *server.Server) error {
 	pw := readPassword("RESTIC_NEWPASSWORD", "enter password for new key: ")
 	pw2 := readPassword("RESTIC_NEWPASSWORD", "enter password again: ")
 
@@ -97,7 +97,7 @@ func changePassword(s restic.Server) error {
 	}
 
 	// add new key
-	id, err := restic.AddKey(s, pw, s.Key())
+	id, err := server.AddKey(s, pw, s.Key())
 	if err != nil {
 		return fmt.Errorf("creating new key failed: %v\n", err)
 	}
diff --git a/cmd/restic/cmd_ls.go b/cmd/restic/cmd_ls.go
index da07bc2aa..ddbe460a3 100644
--- a/cmd/restic/cmd_ls.go
+++ b/cmd/restic/cmd_ls.go
@@ -7,6 +7,7 @@ import (
 
 	"github.com/restic/restic"
 	"github.com/restic/restic/backend"
+	"github.com/restic/restic/server"
 )
 
 type CmdLs struct{}
@@ -37,7 +38,7 @@ func printNode(prefix string, n *restic.Node) string {
 	}
 }
 
-func printTree(prefix string, s restic.Server, blob restic.Blob) error {
+func printTree(prefix string, s *server.Server, blob server.Blob) error {
 	tree, err := restic.LoadTree(s, blob)
 	if err != nil {
 		return err
diff --git a/cmd/restic/main.go b/cmd/restic/main.go
index cc282bdb2..806fcd0c1 100644
--- a/cmd/restic/main.go
+++ b/cmd/restic/main.go
@@ -15,6 +15,7 @@ import (
 	"github.com/restic/restic/backend/local"
 	"github.com/restic/restic/backend/sftp"
 	"github.com/restic/restic/debug"
+	"github.com/restic/restic/server"
 )
 
 var version = "compiled manually"
@@ -72,9 +73,9 @@ func (cmd CmdInit) Execute(args []string) error {
 		os.Exit(1)
 	}
 
-	s := restic.NewServer(be)
+	s := server.NewServer(be)
 
-	_, err = restic.CreateKey(s, pw)
+	_, err = server.CreateKey(s, pw)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "creating key in backend at %s failed: %v\n", opts.Repo, err)
 		os.Exit(1)
@@ -134,21 +135,21 @@ func create(u string) (backend.Backend, error) {
 	return sftp.Create(url.Path[1:], "ssh", args...)
 }
 
-func OpenRepo() (restic.Server, error) {
+func OpenRepo() (*server.Server, error) {
 	if opts.Repo == "" {
-		return restic.Server{}, errors.New("Please specify repository location (-r)")
+		return nil, errors.New("Please specify repository location (-r)")
 	}
 
 	be, err := open(opts.Repo)
 	if err != nil {
-		return restic.Server{}, err
+		return nil, err
 	}
 
-	s := restic.NewServer(be)
+	s := server.NewServer(be)
 
 	err = s.SearchKey(readPassword("RESTIC_PASSWORD", "enter password for repository: "))
 	if err != nil {
-		return restic.Server{}, fmt.Errorf("unable to open repo: %v", err)
+		return nil, fmt.Errorf("unable to open repo: %v", err)
 	}
 
 	return s, nil
diff --git a/key_test.go b/key_test.go
deleted file mode 100644
index 1048a0cf8..000000000
--- a/key_test.go
+++ /dev/null
@@ -1,55 +0,0 @@
-package restic_test
-
-import (
-	"flag"
-	"io/ioutil"
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/restic/restic"
-	"github.com/restic/restic/backend/local"
-	. "github.com/restic/restic/test"
-)
-
-var testPassword = "foobar"
-var testCleanup = flag.Bool("test.cleanup", true, "clean up after running tests (remove local backend directory with all content)")
-var testTempDir = flag.String("test.tempdir", "", "use this directory for temporary storage (default: system temp dir)")
-
-func setupBackend(t testing.TB) restic.Server {
-	tempdir, err := ioutil.TempDir(*testTempDir, "restic-test-")
-	OK(t, err)
-
-	// create repository below temp dir
-	b, err := local.Create(filepath.Join(tempdir, "repo"))
-	OK(t, err)
-
-	// set cache dir
-	err = os.Setenv("RESTIC_CACHE", filepath.Join(tempdir, "cache"))
-	OK(t, err)
-
-	return restic.NewServer(b)
-}
-
-func teardownBackend(t testing.TB, s restic.Server) {
-	if !*testCleanup {
-		l := s.Backend().(*local.Local)
-		t.Logf("leaving local backend at %s\n", l.Location())
-		return
-	}
-
-	OK(t, s.Delete())
-}
-
-func setupKey(t testing.TB, s restic.Server, password string) *restic.Key {
-	k, err := restic.CreateKey(s, password)
-	OK(t, err)
-
-	return k
-}
-
-func TestRepo(t *testing.T) {
-	s := setupBackend(t)
-	defer teardownBackend(t, s)
-	_ = setupKey(t, s, testPassword)
-}
diff --git a/map.go b/map.go
index d80ca8258..b2c708ef5 100644
--- a/map.go
+++ b/map.go
@@ -1,7 +1,6 @@
 package restic
 
 import (
-	"bytes"
 	"encoding/json"
 	"errors"
 	"sort"
@@ -9,10 +8,11 @@ import (
 
 	"github.com/restic/restic/backend"
 	"github.com/restic/restic/debug"
+	"github.com/restic/restic/server"
 )
 
 type Map struct {
-	list []Blob
+	list []server.Blob
 	m    sync.Mutex
 }
 
@@ -20,11 +20,11 @@ var ErrBlobNotFound = errors.New("Blob not found")
 
 func NewMap() *Map {
 	return &Map{
-		list: []Blob{},
+		list: []server.Blob{},
 	}
 }
 
-func (bl *Map) find(blob Blob, checkSize bool) (int, Blob, error) {
+func (bl *Map) find(blob server.Blob, checkSize bool) (int, server.Blob, error) {
 	pos := sort.Search(len(bl.list), func(i int) bool {
 		return blob.ID.Compare(bl.list[i].ID) >= 0
 	})
@@ -36,10 +36,10 @@ func (bl *Map) find(blob Blob, checkSize bool) (int, Blob, error) {
 		}
 	}
 
-	return pos, Blob{}, ErrBlobNotFound
+	return pos, server.Blob{}, ErrBlobNotFound
 }
 
-func (bl *Map) Find(blob Blob) (Blob, error) {
+func (bl *Map) Find(blob server.Blob) (server.Blob, error) {
 	bl.m.Lock()
 	defer bl.m.Unlock()
 
@@ -47,11 +47,11 @@ func (bl *Map) Find(blob Blob) (Blob, error) {
 	return blob, err
 }
 
-func (bl *Map) FindID(id backend.ID) (Blob, error) {
+func (bl *Map) FindID(id backend.ID) (server.Blob, error) {
 	bl.m.Lock()
 	defer bl.m.Unlock()
 
-	_, blob, err := bl.find(Blob{ID: id}, false)
+	_, blob, err := bl.find(server.Blob{ID: id}, false)
 	return blob, err
 }
 
@@ -66,7 +66,7 @@ func (bl *Map) Merge(other *Map) {
 	}
 }
 
-func (bl *Map) insert(blob Blob) Blob {
+func (bl *Map) insert(blob server.Blob) server.Blob {
 	pos, b, err := bl.find(blob, true)
 	if err == nil {
 		// already present
@@ -75,14 +75,14 @@ func (bl *Map) insert(blob Blob) Blob {
 
 	// insert blob
 	// https://code.google.com/p/go-wiki/wiki/SliceTricks
-	bl.list = append(bl.list, Blob{})
+	bl.list = append(bl.list, server.Blob{})
 	copy(bl.list[pos+1:], bl.list[pos:])
 	bl.list[pos] = blob
 
 	return blob
 }
 
-func (bl *Map) Insert(blob Blob) Blob {
+func (bl *Map) Insert(blob server.Blob) server.Blob {
 	bl.m.Lock()
 	defer bl.m.Unlock()
 
@@ -152,7 +152,7 @@ func (bl *Map) Equals(other *Map) bool {
 
 // Each calls f for each blob in the Map. While Each is running, no other
 // operation is possible, since a mutex is held for the whole time.
-func (bl *Map) Each(f func(blob Blob)) {
+func (bl *Map) Each(f func(blob server.Blob)) {
 	bl.m.Lock()
 	defer bl.m.Unlock()
 
@@ -162,13 +162,13 @@ func (bl *Map) Each(f func(blob Blob)) {
 }
 
 // Select returns a list of of blobs from the plaintext IDs given in list.
-func (bl *Map) Select(list backend.IDs) (Blobs, error) {
+func (bl *Map) Select(list backend.IDs) (server.Blobs, error) {
 	bl.m.Lock()
 	defer bl.m.Unlock()
 
-	blobs := make(Blobs, 0, len(list))
+	blobs := make(server.Blobs, 0, len(list))
 	for _, id := range list {
-		_, blob, err := bl.find(Blob{ID: id}, false)
+		_, blob, err := bl.find(server.Blob{ID: id}, false)
 		if err != nil {
 			return nil, err
 		}
@@ -210,27 +210,10 @@ func (m *Map) DeleteID(id backend.ID) {
 	m.m.Lock()
 	defer m.m.Unlock()
 
-	pos, _, err := m.find(Blob{ID: id}, false)
+	pos, _, err := m.find(server.Blob{ID: id}, false)
 	if err != nil {
 		return
 	}
 
 	m.list = append(m.list[:pos], m.list[pos+1:]...)
 }
-
-// Compare compares two blobs by comparing the ID and the size. It returns -1,
-// 0, or 1.
-func (blob Blob) Compare(other Blob) int {
-	if res := bytes.Compare(other.ID, blob.ID); res != 0 {
-		return res
-	}
-
-	if blob.Size < other.Size {
-		return -1
-	}
-	if blob.Size > other.Size {
-		return 1
-	}
-
-	return 0
-}
diff --git a/map_test.go b/map_test.go
index 1c91542ad..f83fa6828 100644
--- a/map_test.go
+++ b/map_test.go
@@ -12,6 +12,7 @@ import (
 
 	"github.com/restic/restic"
 	"github.com/restic/restic/backend"
+	"github.com/restic/restic/server"
 	. "github.com/restic/restic/test"
 )
 
@@ -26,8 +27,8 @@ func randomID() []byte {
 	return buf
 }
 
-func newBlob() restic.Blob {
-	return restic.Blob{
+func newBlob() server.Blob {
+	return server.Blob{
 		ID:          randomID(),
 		Size:        uint64(mrand.Uint32()),
 		Storage:     randomID(),
@@ -46,7 +47,7 @@ func TestMap(t *testing.T) {
 		bl.Insert(newBlob())
 	}
 
-	b2, err := bl.Find(restic.Blob{ID: b.ID, Size: b.Size})
+	b2, err := bl.Find(server.Blob{ID: b.ID, Size: b.Size})
 	OK(t, err)
 	Assert(t, b2.Compare(b) == 0, "items are not equal: want %v, got %v", b, b2)
 
@@ -78,7 +79,7 @@ func TestMap(t *testing.T) {
 // Test JSON encode/decode
 func TestMapJSON(t *testing.T) {
 	bl := restic.NewMap()
-	b := restic.Blob{ID: randomID()}
+	b := server.Blob{ID: randomID()}
 	bl.Insert(b)
 
 	b2, err := bl.Find(b)
diff --git a/node.go b/node.go
index 15903348d..80bf8ffb3 100644
--- a/node.go
+++ b/node.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/juju/arrar"
 	"github.com/restic/restic/backend"
+	"github.com/restic/restic/server"
 )
 
 type Node struct {
@@ -37,7 +38,7 @@ type Node struct {
 
 	path  string
 	err   error
-	blobs Blobs
+	blobs server.Blobs
 }
 
 func (n Node) String() string {
@@ -95,7 +96,7 @@ func nodeTypeFromFileInfo(path string, fi os.FileInfo) string {
 	return ""
 }
 
-func CreateNodeAt(node *Node, m *Map, s Server, path string) error {
+func CreateNodeAt(node *Node, m *Map, s *server.Server, path string) error {
 	switch node.Type {
 	case "dir":
 		err := os.Mkdir(path, node.Mode)
diff --git a/restorer.go b/restorer.go
index a1686a8bb..ef362a159 100644
--- a/restorer.go
+++ b/restorer.go
@@ -9,10 +9,11 @@ import (
 
 	"github.com/juju/arrar"
 	"github.com/restic/restic/backend"
+	"github.com/restic/restic/server"
 )
 
 type Restorer struct {
-	s  Server
+	s  *server.Server
 	sn *Snapshot
 
 	Error  func(dir string, node *Node, err error) error
@@ -20,7 +21,7 @@ type Restorer struct {
 }
 
 // NewRestorer creates a restorer preloaded with the content from the snapshot snid.
-func NewRestorer(s Server, snid backend.ID) (*Restorer, error) {
+func NewRestorer(s *server.Server, snid backend.ID) (*Restorer, error) {
 	r := &Restorer{s: s}
 
 	var err error
@@ -36,7 +37,7 @@ func NewRestorer(s Server, snid backend.ID) (*Restorer, error) {
 	return r, nil
 }
 
-func (res *Restorer) to(dst string, dir string, treeBlob Blob) error {
+func (res *Restorer) to(dst string, dir string, treeBlob server.Blob) error {
 	tree, err := LoadTree(res.s, treeBlob)
 	if err != nil {
 		return res.Error(dir, nil, arrar.Annotate(err, "LoadTree"))
diff --git a/blob.go b/server/blob.go
similarity index 63%
rename from blob.go
rename to server/blob.go
index 949c9ce27..093a1033a 100644
--- a/blob.go
+++ b/server/blob.go
@@ -1,6 +1,7 @@
-package restic
+package server
 
 import (
+	"bytes"
 	"fmt"
 
 	"github.com/restic/restic/backend"
@@ -28,3 +29,20 @@ func (b Blob) String() string {
 		b.ID.Str(), b.Size,
 		b.Storage.Str(), b.StorageSize)
 }
+
+// Compare compares two blobs by comparing the ID and the size. It returns -1,
+// 0, or 1.
+func (blob Blob) Compare(other Blob) int {
+	if res := bytes.Compare(other.ID, blob.ID); res != 0 {
+		return res
+	}
+
+	if blob.Size < other.Size {
+		return -1
+	}
+	if blob.Size > other.Size {
+		return 1
+	}
+
+	return 0
+}
diff --git a/key.go b/server/key.go
similarity index 93%
rename from key.go
rename to server/key.go
index 70e16aa40..9d4db1b63 100644
--- a/key.go
+++ b/server/key.go
@@ -1,4 +1,4 @@
-package restic
+package server
 
 import (
 	"crypto/rand"
@@ -52,12 +52,12 @@ type Key struct {
 
 // CreateKey initializes a master key in the given backend and encrypts it with
 // the password.
-func CreateKey(s Server, password string) (*Key, error) {
+func CreateKey(s *Server, password string) (*Key, error) {
 	return AddKey(s, password, nil)
 }
 
 // OpenKey tries do decrypt the key specified by name with the given password.
-func OpenKey(s Server, name string, password string) (*Key, error) {
+func OpenKey(s *Server, name string, password string) (*Key, error) {
 	k, err := LoadKey(s, name)
 	if err != nil {
 		return nil, err
@@ -104,7 +104,7 @@ func OpenKey(s Server, name string, password string) (*Key, error) {
 
 // SearchKey tries to decrypt all keys in the backend with the given password.
 // If none could be found, ErrNoKeyFound is returned.
-func SearchKey(s Server, password string) (*Key, error) {
+func SearchKey(s *Server, password string) (*Key, error) {
 	// try all keys in repo
 	done := make(chan struct{})
 	defer close(done)
@@ -121,7 +121,7 @@ func SearchKey(s Server, password string) (*Key, error) {
 }
 
 // LoadKey loads a key from the backend.
-func LoadKey(s Server, name string) (*Key, error) {
+func LoadKey(s *Server, name string) (*Key, error) {
 	// extract data from repo
 	rd, err := s.be.Get(backend.Key, name)
 	if err != nil {
@@ -141,7 +141,7 @@ func LoadKey(s Server, name string) (*Key, error) {
 }
 
 // AddKey adds a new key to an already existing repository.
-func AddKey(s Server, password string, template *Key) (*Key, error) {
+func AddKey(s *Server, password string, template *Key) (*Key, error) {
 	// fill meta data about key
 	newkey := &Key{
 		Created: time.Now(),
@@ -196,7 +196,7 @@ func AddKey(s Server, password string, template *Key) (*Key, error) {
 		return nil, err
 	}
 
-	newkey.Data, err = crypto.Encrypt(newkey.user, GetChunkBuf("key"), buf)
+	newkey.Data, err = crypto.Encrypt(newkey.user, nil, buf)
 
 	// dump as json
 	buf, err = json.Marshal(newkey)
@@ -226,8 +226,6 @@ func AddKey(s Server, password string, template *Key) (*Key, error) {
 
 	newkey.name = name
 
-	FreeChunkBuf("key", newkey.Data)
-
 	return newkey, nil
 }
 
diff --git a/server/key_test.go b/server/key_test.go
new file mode 100644
index 000000000..468e09c65
--- /dev/null
+++ b/server/key_test.go
@@ -0,0 +1,13 @@
+package server_test
+
+import (
+	"testing"
+
+	. "github.com/restic/restic/test"
+)
+
+func TestRepo(t *testing.T) {
+	s := SetupBackend(t)
+	defer TeardownBackend(t, s)
+	_ = SetupKey(t, s, TestPassword)
+}
diff --git a/server/pool.go b/server/pool.go
new file mode 100644
index 000000000..304d20e1b
--- /dev/null
+++ b/server/pool.go
@@ -0,0 +1,21 @@
+package server
+
+import (
+	"sync"
+
+	"github.com/restic/restic/chunker"
+)
+
+var bufPool = sync.Pool{
+	New: func() interface{} {
+		return make([]byte, chunker.MinSize)
+	},
+}
+
+func getBuf() []byte {
+	return bufPool.Get().([]byte)
+}
+
+func freeBuf(data []byte) {
+	bufPool.Put(data)
+}
diff --git a/server.go b/server/server.go
similarity index 68%
rename from server.go
rename to server/server.go
index 7c7dce850..d00d47f4f 100644
--- a/server.go
+++ b/server/server.go
@@ -1,4 +1,4 @@
-package restic
+package server
 
 import (
 	"crypto/sha256"
@@ -7,12 +7,9 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"sync"
 
 	"github.com/restic/restic/backend"
 	"github.com/restic/restic/chunker"
-	"github.com/restic/restic/crypto"
-	"github.com/restic/restic/debug"
 )
 
 type Server struct {
@@ -20,8 +17,8 @@ type Server struct {
 	key *Key
 }
 
-func NewServer(be backend.Backend) Server {
-	return Server{be: be}
+func NewServer(be backend.Backend) *Server {
+	return &Server{be: be}
 }
 
 func (s *Server) SetKey(k *Key) {
@@ -36,19 +33,19 @@ func (s *Server) ChunkerPolynomial() chunker.Pol {
 // Find loads the list of all blobs of type t and searches for names which start
 // with prefix. If none is found, nil and ErrNoIDPrefixFound is returned. If
 // more than one is found, nil and ErrMultipleIDMatches is returned.
-func (s Server) Find(t backend.Type, prefix string) (string, error) {
+func (s *Server) Find(t backend.Type, prefix string) (string, error) {
 	return backend.Find(s.be, t, prefix)
 }
 
 // FindSnapshot takes a string and tries to find a snapshot whose ID matches
 // the string as closely as possible.
-func (s Server) FindSnapshot(name string) (string, error) {
+func (s *Server) FindSnapshot(name string) (string, error) {
 	return backend.FindSnapshot(s.be, name)
 }
 
 // PrefixLength returns the number of bytes required so that all prefixes of
 // all IDs of type t are unique.
-func (s Server) PrefixLength(t backend.Type) (int, error) {
+func (s *Server) PrefixLength(t backend.Type) (int, error) {
 	return backend.PrefixLength(s.be, t)
 }
 
@@ -56,7 +53,7 @@ func (s Server) PrefixLength(t backend.Type) (int, error) {
 // backend. If the blob specifies an ID, the decrypted plaintext is checked
 // against this ID. The same goes for blob.Size and blob.StorageSize: If they
 // are set to a value > 0, this value is checked.
-func (s Server) Load(t backend.Type, blob Blob) ([]byte, error) {
+func (s *Server) Load(t backend.Type, blob Blob) ([]byte, error) {
 	// load data
 	rd, err := s.be.Get(t, blob.Storage.String())
 	if err != nil {
@@ -101,13 +98,13 @@ func (s Server) Load(t backend.Type, blob Blob) ([]byte, error) {
 }
 
 // Load tries to load and decrypt content identified by t and id from the backend.
-func (s Server) LoadID(t backend.Type, storageID backend.ID) ([]byte, error) {
+func (s *Server) LoadID(t backend.Type, storageID backend.ID) ([]byte, error) {
 	return s.Load(t, Blob{Storage: storageID})
 }
 
 // LoadJSON calls Load() to get content from the backend and afterwards calls
 // json.Unmarshal on the item.
-func (s Server) LoadJSON(t backend.Type, blob Blob, item interface{}) error {
+func (s *Server) LoadJSON(t backend.Type, blob Blob, item interface{}) error {
 	buf, err := s.Load(t, blob)
 	if err != nil {
 		return err
@@ -118,7 +115,7 @@ func (s Server) LoadJSON(t backend.Type, blob Blob, item interface{}) error {
 
 // LoadJSONID calls Load() to get content from the backend and afterwards calls
 // json.Unmarshal on the item.
-func (s Server) LoadJSONID(t backend.Type, id backend.ID, item interface{}) error {
+func (s *Server) LoadJSONID(t backend.Type, id backend.ID, item interface{}) error {
 	// read
 	rd, err := s.be.Get(t, id.String())
 	if err != nil {
@@ -144,7 +141,7 @@ func (s Server) LoadJSONID(t backend.Type, id backend.ID, item interface{}) erro
 }
 
 // Save encrypts data and stores it to the backend as type t.
-func (s Server) Save(t backend.Type, data []byte, id backend.ID) (Blob, error) {
+func (s *Server) Save(t backend.Type, data []byte, id backend.ID) (Blob, error) {
 	if id == nil {
 		// compute plaintext hash
 		id = backend.Hash(data)
@@ -156,20 +153,8 @@ func (s Server) Save(t backend.Type, data []byte, id backend.ID) (Blob, error) {
 		Size: uint64(len(data)),
 	}
 
-	var ciphertext []byte
-
-	// if the data is small enough, use a slice from the pool
-	if len(data) <= maxCiphertextSize-crypto.Extension {
-		ciphertext = GetChunkBuf("ch.Save()")
-		defer FreeChunkBuf("ch.Save()", ciphertext)
-	} else {
-		l := len(data) + crypto.Extension
-
-		debug.Log("Server.Save", "create large slice of %d bytes for ciphertext", l)
-
-		// use a new slice
-		ciphertext = make([]byte, l)
-	}
+	ciphertext := getBuf()
+	defer freeBuf(ciphertext)
 
 	// encrypt blob
 	ciphertext, err := s.Encrypt(ciphertext, data)
@@ -203,7 +188,7 @@ func (s Server) Save(t backend.Type, data []byte, id backend.ID) (Blob, error) {
 }
 
 // SaveFrom encrypts data read from rd and stores it to the backend as type t.
-func (s Server) SaveFrom(t backend.Type, id backend.ID, length uint, rd io.Reader) (Blob, error) {
+func (s *Server) SaveFrom(t backend.Type, id backend.ID, length uint, rd io.Reader) (Blob, error) {
 	if id == nil {
 		return Blob{}, errors.New("id is nil")
 	}
@@ -244,7 +229,7 @@ func (s Server) SaveFrom(t backend.Type, id backend.ID, length uint, rd io.Reade
 
 // SaveJSON serialises item as JSON and encrypts and saves it in the backend as
 // type t.
-func (s Server) SaveJSON(t backend.Type, item interface{}) (Blob, error) {
+func (s *Server) SaveJSON(t backend.Type, item interface{}) (Blob, error) {
 	backendBlob, err := s.be.Create()
 	if err != nil {
 		return Blob{}, fmt.Errorf("Create: %v", err)
@@ -284,12 +269,12 @@ func (s Server) SaveJSON(t backend.Type, item interface{}) (Blob, error) {
 }
 
 // Returns the backend used for this server.
-func (s Server) Backend() backend.Backend {
+func (s *Server) Backend() backend.Backend {
 	return s.be
 }
 
 func (s *Server) SearchKey(password string) error {
-	key, err := SearchKey(*s, password)
+	key, err := SearchKey(s, password)
 	if err != nil {
 		return err
 	}
@@ -299,7 +284,7 @@ func (s *Server) SearchKey(password string) error {
 	return nil
 }
 
-func (s Server) Decrypt(ciphertext []byte) ([]byte, error) {
+func (s *Server) Decrypt(ciphertext []byte) ([]byte, error) {
 	if s.key == nil {
 		return nil, errors.New("key for server not set")
 	}
@@ -307,7 +292,7 @@ func (s Server) Decrypt(ciphertext []byte) ([]byte, error) {
 	return s.key.Decrypt([]byte{}, ciphertext)
 }
 
-func (s Server) Encrypt(ciphertext, plaintext []byte) ([]byte, error) {
+func (s *Server) Encrypt(ciphertext, plaintext []byte) ([]byte, error) {
 	if s.key == nil {
 		return nil, errors.New("key for server not set")
 	}
@@ -315,67 +300,12 @@ func (s Server) Encrypt(ciphertext, plaintext []byte) ([]byte, error) {
 	return s.key.Encrypt(ciphertext, plaintext)
 }
 
-func (s Server) Key() *Key {
+func (s *Server) Key() *Key {
 	return s.key
 }
 
-type ServerStats struct {
-	Blobs, Trees uint
-}
-
-// Stats returns statistics for this backend and the server.
-func (s Server) Stats() (ServerStats, error) {
-	blobs := backend.NewIDSet()
-
-	// load all trees, in parallel
-	worker := func(wg *sync.WaitGroup, b <-chan Blob) {
-		for blob := range b {
-			tree, err := LoadTree(s, blob)
-			// ignore error and advance to next tree
-			if err != nil {
-				return
-			}
-
-			for _, id := range tree.Map.StorageIDs() {
-				blobs.Insert(id)
-			}
-		}
-		wg.Done()
-	}
-
-	blobCh := make(chan Blob)
-
-	// start workers
-	var wg sync.WaitGroup
-	for i := 0; i < maxConcurrency; i++ {
-		wg.Add(1)
-		go worker(&wg, blobCh)
-	}
-
-	// list ids
-	trees := 0
-	done := make(chan struct{})
-	defer close(done)
-	for name := range s.List(backend.Tree, done) {
-		trees++
-		id, err := backend.ParseID(name)
-		if err != nil {
-			debug.Log("Server.Stats", "unable to parse name %v as id: %v", name, err)
-			continue
-		}
-		blobCh <- Blob{Storage: id}
-	}
-
-	close(blobCh)
-
-	// wait for workers
-	wg.Wait()
-
-	return ServerStats{Blobs: uint(blobs.Len()), Trees: uint(trees)}, nil
-}
-
 // Count returns the number of blobs of a given type in the backend.
-func (s Server) Count(t backend.Type) (n int) {
+func (s *Server) Count(t backend.Type) (n int) {
 	for _ = range s.List(t, nil) {
 		n++
 	}
@@ -385,23 +315,27 @@ func (s Server) Count(t backend.Type) (n int) {
 
 // Proxy methods to backend
 
-func (s Server) List(t backend.Type, done <-chan struct{}) <-chan string {
+func (s *Server) Get(t backend.Type, name string) (io.ReadCloser, error) {
+	return s.be.Get(t, name)
+}
+
+func (s *Server) List(t backend.Type, done <-chan struct{}) <-chan string {
 	return s.be.List(t, done)
 }
 
-func (s Server) Test(t backend.Type, name string) (bool, error) {
+func (s *Server) Test(t backend.Type, name string) (bool, error) {
 	return s.be.Test(t, name)
 }
 
-func (s Server) Remove(t backend.Type, name string) error {
+func (s *Server) Remove(t backend.Type, name string) error {
 	return s.be.Remove(t, name)
 }
 
-func (s Server) Close() error {
+func (s *Server) Close() error {
 	return s.be.Close()
 }
 
-func (s Server) Delete() error {
+func (s *Server) Delete() error {
 	if b, ok := s.be.(backend.Deleter); ok {
 		return b.Delete()
 	}
@@ -409,10 +343,10 @@ func (s Server) Delete() error {
 	return errors.New("Delete() called for backend that does not implement this method")
 }
 
-func (s Server) ID() string {
+func (s *Server) ID() string {
 	return s.be.ID()
 }
 
-func (s Server) Location() string {
+func (s *Server) Location() string {
 	return s.be.Location()
 }
diff --git a/server_test.go b/server/server_test.go
similarity index 71%
rename from server_test.go
rename to server/server_test.go
index 54feb378e..414b4f0cc 100644
--- a/server_test.go
+++ b/server/server_test.go
@@ -1,10 +1,11 @@
-package restic_test
+package server_test
 
 import (
 	"bytes"
 	"crypto/rand"
 	"crypto/sha256"
 	"encoding/json"
+	"flag"
 	"io"
 	"testing"
 
@@ -13,6 +14,8 @@ import (
 	. "github.com/restic/restic/test"
 )
 
+var benchTestDir = flag.String("test.dir", ".", "dir used in benchmarks (default: .)")
+
 type testJSONStruct struct {
 	Foo uint32
 	Bar string
@@ -24,9 +27,9 @@ var serverTests = []testJSONStruct{
 }
 
 func TestSaveJSON(t *testing.T) {
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
+	server := SetupBackend(t)
+	defer TeardownBackend(t, server)
+	key := SetupKey(t, server, "geheim")
 	server.SetKey(key)
 
 	for _, obj := range serverTests {
@@ -45,9 +48,9 @@ func TestSaveJSON(t *testing.T) {
 }
 
 func BenchmarkSaveJSON(t *testing.B) {
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
+	server := SetupBackend(t)
+	defer TeardownBackend(t, server)
+	key := SetupKey(t, server, "geheim")
 	server.SetKey(key)
 
 	obj := serverTests[0]
@@ -72,9 +75,9 @@ func BenchmarkSaveJSON(t *testing.B) {
 var testSizes = []int{5, 23, 2<<18 + 23, 1 << 20}
 
 func TestSaveFrom(t *testing.T) {
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
+	server := SetupBackend(t)
+	defer TeardownBackend(t, server)
+	key := SetupKey(t, server, "geheim")
 	server.SetKey(key)
 
 	for _, size := range testSizes {
@@ -102,9 +105,9 @@ func TestSaveFrom(t *testing.T) {
 }
 
 func BenchmarkSaveFrom(t *testing.B) {
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
+	server := SetupBackend(t)
+	defer TeardownBackend(t, server)
+	key := SetupKey(t, server, "geheim")
 	server.SetKey(key)
 
 	size := 4 << 20 // 4MiB
@@ -125,37 +128,18 @@ func BenchmarkSaveFrom(t *testing.B) {
 	}
 }
 
-func TestServerStats(t *testing.T) {
-	if *benchArchiveDirectory == "" {
-		t.Skip("benchdir not set, skipping TestServerStats")
-	}
-
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
-	server.SetKey(key)
-
-	// archive a few files
-	sn := snapshot(t, server, *benchArchiveDirectory, nil)
-	t.Logf("archived snapshot %v", sn.ID())
-
-	stats, err := server.Stats()
-	OK(t, err)
-	t.Logf("stats: %v", stats)
-}
-
 func TestLoadJSONID(t *testing.T) {
-	if *benchArchiveDirectory == "" {
+	if *benchTestDir == "" {
 		t.Skip("benchdir not set, skipping TestServerStats")
 	}
 
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
+	server := SetupBackend(t)
+	defer TeardownBackend(t, server)
+	key := SetupKey(t, server, "geheim")
 	server.SetKey(key)
 
 	// archive a few files
-	sn := snapshot(t, server, *benchArchiveDirectory, nil)
+	sn := SnapshotDir(t, server, *benchTestDir, nil)
 	t.Logf("archived snapshot %v", sn.ID())
 
 	// benchmark loading first tree
@@ -173,17 +157,17 @@ func TestLoadJSONID(t *testing.T) {
 }
 
 func BenchmarkLoadJSONID(t *testing.B) {
-	if *benchArchiveDirectory == "" {
+	if *benchTestDir == "" {
 		t.Skip("benchdir not set, skipping TestServerStats")
 	}
 
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
+	server := SetupBackend(t)
+	defer TeardownBackend(t, server)
+	key := SetupKey(t, server, "geheim")
 	server.SetKey(key)
 
 	// archive a few files
-	sn := snapshot(t, server, *benchArchiveDirectory, nil)
+	sn := SnapshotDir(t, server, *benchTestDir, nil)
 	t.Logf("archived snapshot %v", sn.ID())
 
 	t.ResetTimer()
diff --git a/snapshot.go b/snapshot.go
index e1460343d..68cf007df 100644
--- a/snapshot.go
+++ b/snapshot.go
@@ -7,19 +7,20 @@ import (
 	"time"
 
 	"github.com/restic/restic/backend"
+	"github.com/restic/restic/server"
 )
 
 type Snapshot struct {
-	Time     time.Time  `json:"time"`
-	Parent   backend.ID `json:"parent,omitempty"`
-	Tree     Blob       `json:"tree"`
-	Paths    []string   `json:"paths"`
-	Hostname string     `json:"hostname,omitempty"`
-	Username string     `json:"username,omitempty"`
-	UID      uint32     `json:"uid,omitempty"`
-	GID      uint32     `json:"gid,omitempty"`
-	UserID   string     `json:"userid,omitempty"`
-	GroupID  string     `json:"groupid,omitempty"`
+	Time     time.Time   `json:"time"`
+	Parent   backend.ID  `json:"parent,omitempty"`
+	Tree     server.Blob `json:"tree"`
+	Paths    []string    `json:"paths"`
+	Hostname string      `json:"hostname,omitempty"`
+	Username string      `json:"username,omitempty"`
+	UID      uint32      `json:"uid,omitempty"`
+	GID      uint32      `json:"gid,omitempty"`
+	UserID   string      `json:"userid,omitempty"`
+	GroupID  string      `json:"groupid,omitempty"`
 
 	id backend.ID // plaintext ID, used during restore
 }
@@ -49,7 +50,7 @@ func NewSnapshot(paths []string) (*Snapshot, error) {
 	return sn, nil
 }
 
-func LoadSnapshot(s Server, id backend.ID) (*Snapshot, error) {
+func LoadSnapshot(s *server.Server, id backend.ID) (*Snapshot, error) {
 	sn := &Snapshot{id: id}
 	err := s.LoadJSONID(backend.Snapshot, id, sn)
 	if err != nil {
diff --git a/snapshot_test.go b/snapshot_test.go
index e71fbff40..3e13dd1f1 100644
--- a/snapshot_test.go
+++ b/snapshot_test.go
@@ -5,10 +5,11 @@ import (
 	"time"
 
 	"github.com/restic/restic"
+	"github.com/restic/restic/server"
 	. "github.com/restic/restic/test"
 )
 
-func testSnapshot(t *testing.T, s restic.Server) {
+func testSnapshot(t *testing.T, s *server.Server) {
 	var err error
 	sn, err := restic.NewSnapshot([]string{"/home/foobar"})
 	OK(t, err)
@@ -22,8 +23,8 @@ func testSnapshot(t *testing.T, s restic.Server) {
 }
 
 func TestSnapshot(t *testing.T) {
-	repo := setupBackend(t)
-	defer teardownBackend(t, repo)
+	s := SetupBackend(t)
+	defer TeardownBackend(t, s)
 
-	testSnapshot(t, repo)
+	testSnapshot(t, s)
 }
diff --git a/test/backend.go b/test/backend.go
new file mode 100644
index 000000000..f2cc8dae6
--- /dev/null
+++ b/test/backend.go
@@ -0,0 +1,59 @@
+package test_helper
+
+import (
+	"flag"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/restic/restic"
+	"github.com/restic/restic/backend"
+	"github.com/restic/restic/backend/local"
+	"github.com/restic/restic/server"
+)
+
+var TestPassword = "foobar"
+var TestCleanup = flag.Bool("test.cleanup", true, "clean up after running tests (remove local backend directory with all content)")
+var TestTempDir = flag.String("test.tempdir", "", "use this directory for temporary storage (default: system temp dir)")
+
+func SetupBackend(t testing.TB) *server.Server {
+	tempdir, err := ioutil.TempDir(*TestTempDir, "restic-test-")
+	OK(t, err)
+
+	// create repository below temp dir
+	b, err := local.Create(filepath.Join(tempdir, "repo"))
+	OK(t, err)
+
+	// set cache dir
+	err = os.Setenv("RESTIC_CACHE", filepath.Join(tempdir, "cache"))
+	OK(t, err)
+
+	return server.NewServer(b)
+}
+
+func TeardownBackend(t testing.TB, s *server.Server) {
+	if !*TestCleanup {
+		l := s.Backend().(*local.Local)
+		t.Logf("leaving local backend at %s\n", l.Location())
+		return
+	}
+
+	OK(t, s.Delete())
+}
+
+func SetupKey(t testing.TB, s *server.Server, password string) *server.Key {
+	k, err := server.CreateKey(s, password)
+	OK(t, err)
+
+	return k
+}
+
+func SnapshotDir(t testing.TB, server *server.Server, path string, parent backend.ID) *restic.Snapshot {
+	arch, err := restic.NewArchiver(server)
+	OK(t, err)
+	OK(t, arch.Preload())
+	sn, _, err := arch.Snapshot(nil, []string{path}, parent)
+	OK(t, err)
+	return sn
+}
diff --git a/tree.go b/tree.go
index 9b53182f9..b835e2118 100644
--- a/tree.go
+++ b/tree.go
@@ -7,6 +7,7 @@ import (
 
 	"github.com/restic/restic/backend"
 	"github.com/restic/restic/debug"
+	"github.com/restic/restic/server"
 )
 
 type Tree struct {
@@ -30,7 +31,7 @@ func (t Tree) String() string {
 	return fmt.Sprintf("Tree<%d nodes, %d blobs>", len(t.Nodes), len(t.Map.list))
 }
 
-func LoadTree(s Server, blob Blob) (*Tree, error) {
+func LoadTree(s *server.Server, blob server.Blob) (*Tree, error) {
 	tree := &Tree{}
 	err := s.LoadJSON(backend.Tree, blob, tree)
 	if err != nil {
diff --git a/tree_test.go b/tree_test.go
index 7db23fd5b..89a28b698 100644
--- a/tree_test.go
+++ b/tree_test.go
@@ -22,7 +22,7 @@ var testFiles = []struct {
 
 // prepareDir creates a temporary directory and returns it.
 func prepareDir(t *testing.T) string {
-	tempdir, err := ioutil.TempDir(*testTempDir, "restic-test-")
+	tempdir, err := ioutil.TempDir(*TestTempDir, "restic-test-")
 	OK(t, err)
 
 	for _, test := range testFiles {
@@ -49,7 +49,7 @@ func prepareDir(t *testing.T) string {
 func TestTree(t *testing.T) {
 	dir := prepareDir(t)
 	defer func() {
-		if *testCleanup {
+		if *TestCleanup {
 			OK(t, os.RemoveAll(dir))
 		}
 	}()
diff --git a/walk.go b/walk.go
index a861f5478..2bd3373de 100644
--- a/walk.go
+++ b/walk.go
@@ -4,6 +4,7 @@ import (
 	"path/filepath"
 
 	"github.com/restic/restic/debug"
+	"github.com/restic/restic/server"
 )
 
 type WalkTreeJob struct {
@@ -14,7 +15,7 @@ type WalkTreeJob struct {
 	Tree *Tree
 }
 
-func walkTree(s Server, path string, treeBlob Blob, done chan struct{}, jobCh chan<- WalkTreeJob) {
+func walkTree(s *server.Server, path string, treeBlob server.Blob, done chan struct{}, jobCh chan<- WalkTreeJob) {
 	debug.Log("walkTree", "start on %q (%v)", path, treeBlob)
 	// load tree
 	t, err := LoadTree(s, treeBlob)
@@ -49,7 +50,7 @@ func walkTree(s Server, path string, treeBlob Blob, done chan struct{}, jobCh ch
 // WalkTree walks the tree specified by ID recursively and sends a job for each
 // file and directory it finds. When the channel done is closed, processing
 // stops.
-func WalkTree(server Server, blob Blob, done chan struct{}, jobCh chan<- WalkTreeJob) {
+func WalkTree(server *server.Server, blob server.Blob, done chan struct{}, jobCh chan<- WalkTreeJob) {
 	debug.Log("WalkTree", "start on %v", blob)
 	walkTree(server, "", blob, done, jobCh)
 	close(jobCh)
diff --git a/walk_test.go b/walk_test.go
index 7a49118db..bce1da765 100644
--- a/walk_test.go
+++ b/walk_test.go
@@ -16,9 +16,9 @@ func TestWalkTree(t *testing.T) {
 	dirs, err := filepath.Glob(*testWalkDirectory)
 	OK(t, err)
 
-	server := setupBackend(t)
-	defer teardownBackend(t, server)
-	key := setupKey(t, server, "geheim")
+	server := SetupBackend(t)
+	defer TeardownBackend(t, server)
+	key := SetupKey(t, server, "geheim")
 	server.SetKey(key)
 
 	// archive a few files