diff --git a/.gx/lastpubver b/.gx/lastpubver
index 0067830..72ed71a 100644
--- a/.gx/lastpubver
+++ b/.gx/lastpubver
@@ -1 +1 @@
-0.0.20: Qmeg56ecxRnVv7VWViMrDeEMoBHaNFMs4vQnyQrJ79Zz7i
+0.1.0: QmeMussyD8s3fQ3pM19ZsfbxvomEqPV9FvczLMWyBDYSnS
diff --git a/arc_cache.go b/arc_cache.go
index 4339bb5..78e3135 100644
--- a/arc_cache.go
+++ b/arc_cache.go
@@ -35,7 +35,7 @@ func newARCCachedBS(ctx context.Context, bs Blockstore, lruSize int) (*arccache,
 	return c, nil
 }
 
-func (b *arccache) DeleteBlock(k *cid.Cid) error {
+func (b *arccache) DeleteBlock(k cid.Cid) error {
 	if has, _, ok := b.hasCached(k); ok && !has {
 		return ErrNotFound
 	}
@@ -53,10 +53,10 @@ func (b *arccache) DeleteBlock(k *cid.Cid) error {
 
 // if ok == false has is inconclusive
 // if ok == true then has respons to question: is it contained
-func (b *arccache) hasCached(k *cid.Cid) (has bool, size int, ok bool) {
+func (b *arccache) hasCached(k cid.Cid) (has bool, size int, ok bool) {
 	b.total.Inc()
-	if k == nil {
-		log.Error("nil cid in arccache")
+	if !k.Defined() {
+		log.Error("undefined cid in arccache")
 		// Return cache invalid so the call to blockstore happens
 		// in case of invalid key and correct error is created.
 		return false, -1, false
@@ -75,7 +75,7 @@ func (b *arccache) hasCached(k *cid.Cid) (has bool, size int, ok bool) {
 	return false, -1, false
 }
 
-func (b *arccache) Has(k *cid.Cid) (bool, error) {
+func (b *arccache) Has(k cid.Cid) (bool, error) {
 	if has, _, ok := b.hasCached(k); ok {
 		return has, nil
 	}
@@ -87,7 +87,7 @@ func (b *arccache) Has(k *cid.Cid) (bool, error) {
 	return has, nil
 }
 
-func (b *arccache) GetSize(k *cid.Cid) (int, error) {
+func (b *arccache) GetSize(k cid.Cid) (int, error) {
 	if _, blockSize, ok := b.hasCached(k); ok {
 		return blockSize, nil
 	}
@@ -100,9 +100,9 @@ func (b *arccache) GetSize(k *cid.Cid) (int, error) {
 	return blockSize, err
 }
 
-func (b *arccache) Get(k *cid.Cid) (blocks.Block, error) {
-	if k == nil {
-		log.Error("nil cid in arc cache")
+func (b *arccache) Get(k cid.Cid) (blocks.Block, error) {
+	if !k.Defined() {
+		log.Error("undefined cid in arc cache")
 		return nil, ErrNotFound
 	}
 
@@ -154,15 +154,15 @@ func (b *arccache) HashOnRead(enabled bool) {
 	b.blockstore.HashOnRead(enabled)
 }
 
-func (b *arccache) cacheHave(c *cid.Cid, have bool) {
+func (b *arccache) cacheHave(c cid.Cid, have bool) {
 	b.arc.Add(c.KeyString(), cacheHave(have))
 }
 
-func (b *arccache) cacheSize(c *cid.Cid, blockSize int) {
+func (b *arccache) cacheSize(c cid.Cid, blockSize int) {
 	b.arc.Add(c.KeyString(), cacheSize(blockSize))
 }
 
-func (b *arccache) AllKeysChan(ctx context.Context) (<-chan *cid.Cid, error) {
+func (b *arccache) AllKeysChan(ctx context.Context) (<-chan cid.Cid, error) {
 	return b.blockstore.AllKeysChan(ctx)
 }
 
diff --git a/arc_cache_test.go b/arc_cache_test.go
index 2f80819..facbf34 100644
--- a/arc_cache_test.go
+++ b/arc_cache_test.go
@@ -153,7 +153,7 @@ func TestArcCreationFailure(t *testing.T) {
 func TestInvalidKey(t *testing.T) {
 	arc, _, _ := createStores(t)
 
-	bl, err := arc.Get(nil)
+	bl, err := arc.Get(cid.Cid{})
 
 	if bl != nil {
 		t.Fatal("blocks should be nil")
diff --git a/blockstore.go b/blockstore.go
index 4dd670c..6bb8e39 100644
--- a/blockstore.go
+++ b/blockstore.go
@@ -32,12 +32,12 @@ var ErrNotFound = errors.New("blockstore: block not found")
 // Blockstore wraps a Datastore block-centered methods and provides a layer
 // of abstraction which allows to add different caching strategies.
 type Blockstore interface {
-	DeleteBlock(*cid.Cid) error
-	Has(*cid.Cid) (bool, error)
-	Get(*cid.Cid) (blocks.Block, error)
+	DeleteBlock(cid.Cid) error
+	Has(cid.Cid) (bool, error)
+	Get(cid.Cid) (blocks.Block, error)
 
 	// GetSize returns the CIDs mapped BlockSize
-	GetSize(*cid.Cid) (int, error)
+	GetSize(cid.Cid) (int, error)
 
 	// Put puts a given block to the underlying datastore
 	Put(blocks.Block) error
@@ -49,7 +49,7 @@ type Blockstore interface {
 	// AllKeysChan returns a channel from which
 	// the CIDs in the Blockstore can be read. It should respect
 	// the given context, closing the channel if it becomes Done.
-	AllKeysChan(ctx context.Context) (<-chan *cid.Cid, error)
+	AllKeysChan(ctx context.Context) (<-chan cid.Cid, error)
 
 	// HashOnRead specifies if every read block should be
 	// rehashed to make sure it matches its CID.
@@ -114,9 +114,9 @@ func (bs *blockstore) HashOnRead(enabled bool) {
 	bs.rehash = enabled
 }
 
-func (bs *blockstore) Get(k *cid.Cid) (blocks.Block, error) {
-	if k == nil {
-		log.Error("nil cid in blockstore")
+func (bs *blockstore) Get(k cid.Cid) (blocks.Block, error) {
+	if !k.Defined() {
+		log.Error("undefined cid in blockstore")
 		return nil, ErrNotFound
 	}
 
@@ -173,11 +173,11 @@ func (bs *blockstore) PutMany(blocks []blocks.Block) error {
 	return t.Commit()
 }
 
-func (bs *blockstore) Has(k *cid.Cid) (bool, error) {
+func (bs *blockstore) Has(k cid.Cid) (bool, error) {
 	return bs.datastore.Has(dshelp.CidToDsKey(k))
 }
 
-func (bs *blockstore) GetSize(k *cid.Cid) (int, error) {
+func (bs *blockstore) GetSize(k cid.Cid) (int, error) {
 	bdata, err := bs.datastore.Get(dshelp.CidToDsKey(k))
 	if err == ds.ErrNotFound {
 		return -1, ErrNotFound
@@ -188,7 +188,7 @@ func (bs *blockstore) GetSize(k *cid.Cid) (int, error) {
 	return len(bdata), nil
 }
 
-func (bs *blockstore) DeleteBlock(k *cid.Cid) error {
+func (bs *blockstore) DeleteBlock(k cid.Cid) error {
 	err := bs.datastore.Delete(dshelp.CidToDsKey(k))
 	if err == ds.ErrNotFound {
 		return ErrNotFound
@@ -200,7 +200,7 @@ func (bs *blockstore) DeleteBlock(k *cid.Cid) error {
 // this is very simplistic, in the future, take dsq.Query as a param?
 //
 // AllKeysChan respects context.
-func (bs *blockstore) AllKeysChan(ctx context.Context) (<-chan *cid.Cid, error) {
+func (bs *blockstore) AllKeysChan(ctx context.Context) (<-chan cid.Cid, error) {
 
 	// KeysOnly, because that would be _a lot_ of data.
 	q := dsq.Query{KeysOnly: true}
@@ -209,7 +209,7 @@ func (bs *blockstore) AllKeysChan(ctx context.Context) (<-chan *cid.Cid, error)
 		return nil, err
 	}
 
-	output := make(chan *cid.Cid, dsq.KeysOnlyBufSize)
+	output := make(chan cid.Cid, dsq.KeysOnlyBufSize)
 	go func() {
 		defer func() {
 			res.Close() // ensure exit (signals early exit, too)
diff --git a/blockstore_test.go b/blockstore_test.go
index ae71b54..d0fa739 100644
--- a/blockstore_test.go
+++ b/blockstore_test.go
@@ -29,7 +29,7 @@ func TestGetWhenKeyNotPresent(t *testing.T) {
 
 func TestGetWhenKeyIsNil(t *testing.T) {
 	bs := NewBlockstore(ds_sync.MutexWrap(ds.NewMapDatastore()))
-	_, err := bs.Get(nil)
+	_, err := bs.Get(cid.Cid{})
 	if err != ErrNotFound {
 		t.Fail()
 	}
@@ -113,13 +113,13 @@ func TestHashOnRead(t *testing.T) {
 	}
 }
 
-func newBlockStoreWithKeys(t *testing.T, d ds.Datastore, N int) (Blockstore, []*cid.Cid) {
+func newBlockStoreWithKeys(t *testing.T, d ds.Datastore, N int) (Blockstore, []cid.Cid) {
 	if d == nil {
 		d = ds.NewMapDatastore()
 	}
 	bs := NewBlockstore(ds_sync.MutexWrap(d))
 
-	keys := make([]*cid.Cid, N)
+	keys := make([]cid.Cid, N)
 	for i := 0; i < N; i++ {
 		block := blocks.NewBlock([]byte(fmt.Sprintf("some data %d", i)))
 		err := bs.Put(block)
@@ -131,8 +131,8 @@ func newBlockStoreWithKeys(t *testing.T, d ds.Datastore, N int) (Blockstore, []*
 	return bs, keys
 }
 
-func collect(ch <-chan *cid.Cid) []*cid.Cid {
-	var keys []*cid.Cid
+func collect(ch <-chan cid.Cid) []cid.Cid {
+	var keys []cid.Cid
 	for k := range ch {
 		keys = append(keys, k)
 	}
@@ -217,7 +217,7 @@ func TestAllKeysRespectsContext(t *testing.T) {
 
 }
 
-func expectMatches(t *testing.T, expect, actual []*cid.Cid) {
+func expectMatches(t *testing.T, expect, actual []cid.Cid) {
 
 	if len(expect) != len(actual) {
 		t.Errorf("expect and actual differ: %d != %d", len(expect), len(actual))
diff --git a/bloom_cache.go b/bloom_cache.go
index 7e11689..c58120c 100644
--- a/bloom_cache.go
+++ b/bloom_cache.go
@@ -97,7 +97,7 @@ func (b *bloomcache) Rebuild(ctx context.Context) {
 	atomic.StoreInt32(&b.active, 1)
 }
 
-func (b *bloomcache) DeleteBlock(k *cid.Cid) error {
+func (b *bloomcache) DeleteBlock(k cid.Cid) error {
 	if has, ok := b.hasCached(k); ok && !has {
 		return ErrNotFound
 	}
@@ -107,10 +107,10 @@ func (b *bloomcache) DeleteBlock(k *cid.Cid) error {
 
 // if ok == false has is inconclusive
 // if ok == true then has respons to question: is it contained
-func (b *bloomcache) hasCached(k *cid.Cid) (has bool, ok bool) {
+func (b *bloomcache) hasCached(k cid.Cid) (has bool, ok bool) {
 	b.total.Inc()
-	if k == nil {
-		log.Error("nil cid in bloom cache")
+	if !k.Defined() {
+		log.Error("undefined in bloom cache")
 		// Return cache invalid so call to blockstore
 		// in case of invalid key is forwarded deeper
 		return false, false
@@ -125,7 +125,7 @@ func (b *bloomcache) hasCached(k *cid.Cid) (has bool, ok bool) {
 	return false, false
 }
 
-func (b *bloomcache) Has(k *cid.Cid) (bool, error) {
+func (b *bloomcache) Has(k cid.Cid) (bool, error) {
 	if has, ok := b.hasCached(k); ok {
 		return has, nil
 	}
@@ -133,11 +133,11 @@ func (b *bloomcache) Has(k *cid.Cid) (bool, error) {
 	return b.blockstore.Has(k)
 }
 
-func (b *bloomcache) GetSize(k *cid.Cid) (int, error) {
+func (b *bloomcache) GetSize(k cid.Cid) (int, error) {
   return b.blockstore.GetSize(k)
 }
 
-func (b *bloomcache) Get(k *cid.Cid) (blocks.Block, error) {
+func (b *bloomcache) Get(k cid.Cid) (blocks.Block, error) {
 	if has, ok := b.hasCached(k); ok && !has {
 		return nil, ErrNotFound
 	}
@@ -173,7 +173,7 @@ func (b *bloomcache) HashOnRead(enabled bool) {
 	b.blockstore.HashOnRead(enabled)
 }
 
-func (b *bloomcache) AllKeysChan(ctx context.Context) (<-chan *cid.Cid, error) {
+func (b *bloomcache) AllKeysChan(ctx context.Context) (<-chan cid.Cid, error) {
 	return b.blockstore.AllKeysChan(ctx)
 }
 
diff --git a/idstore.go b/idstore.go
index a1ef4d6..2a5bf84 100644
--- a/idstore.go
+++ b/idstore.go
@@ -17,7 +17,7 @@ func NewIdStore(bs Blockstore) Blockstore {
 	return &idstore{bs}
 }
 
-func extractContents(k *cid.Cid) (bool, []byte) {
+func extractContents(k cid.Cid) (bool, []byte) {
 	dmh, err := mh.Decode(k.Hash())
 	if err != nil || dmh.Code != mh.ID {
 		return false, nil
@@ -25,7 +25,7 @@ func extractContents(k *cid.Cid) (bool, []byte) {
 	return true, dmh.Digest
 }
 
-func (b *idstore) DeleteBlock(k *cid.Cid) error {
+func (b *idstore) DeleteBlock(k cid.Cid) error {
 	isId, _ := extractContents(k)
 	if isId {
 		return nil
@@ -33,7 +33,7 @@ func (b *idstore) DeleteBlock(k *cid.Cid) error {
 	return b.bs.DeleteBlock(k)
 }
 
-func (b *idstore) Has(k *cid.Cid) (bool, error) {
+func (b *idstore) Has(k cid.Cid) (bool, error) {
 	isId, _ := extractContents(k)
 	if isId {
 		return true, nil
@@ -41,7 +41,7 @@ func (b *idstore) Has(k *cid.Cid) (bool, error) {
 	return b.bs.Has(k)
 }
 
-func (b *idstore) GetSize(k *cid.Cid) (int, error) {
+func (b *idstore) GetSize(k cid.Cid) (int, error) {
 	isId, bdata := extractContents(k)
 	if isId {
 		return len(bdata), nil
@@ -49,7 +49,7 @@ func (b *idstore) GetSize(k *cid.Cid) (int, error) {
 	return b.bs.GetSize(k)
 }
 
-func (b *idstore) Get(k *cid.Cid) (blocks.Block, error) {
+func (b *idstore) Get(k cid.Cid) (blocks.Block, error) {
 	isId, bdata := extractContents(k)
 	if isId {
 		return blocks.NewBlockWithCid(bdata, k)
@@ -81,6 +81,6 @@ func (b *idstore) HashOnRead(enabled bool) {
 	b.bs.HashOnRead(enabled)
 }
 
-func (b *idstore) AllKeysChan(ctx context.Context) (<-chan *cid.Cid, error) {
+func (b *idstore) AllKeysChan(ctx context.Context) (<-chan cid.Cid, error) {
 	return b.bs.AllKeysChan(ctx)
 }
diff --git a/package.json b/package.json
index 03c640e..bfe3e6a 100644
--- a/package.json
+++ b/package.json
@@ -9,9 +9,9 @@
   "gxDependencies": [
     {
       "author": "stebalien",
-      "hash": "QmWAzSEoqZ6xU6pu8yL8e5WaMb7wtbfbhhN4p1DknUPtr3",
+      "hash": "QmRcHuYzAyswytBuMF78rj3LTChYszomRFXNg4685ZN1WM",
       "name": "go-block-format",
-      "version": "0.1.11"
+      "version": "0.2.0"
     },
     {
       "author": "jbenet",
@@ -33,15 +33,15 @@
     },
     {
       "author": "whyrusleeping",
-      "hash": "QmZFbDTY9jfSBms2MchvYM9oYRbAF19K7Pby47yDBfpPrb",
+      "hash": "QmPSQnBKM9g7BaUcZCvswUJVscQ1ipjmwxN5PXCjkp9EQ7",
       "name": "go-cid",
-      "version": "0.8.0"
+      "version": "0.9.0"
     },
     {
       "author": "hector",
-      "hash": "Qmf1xGr3SyBpiPp3ZDuKkYMh4gnRk9K4QnbL17kstnf35h",
+      "hash": "QmXejiSr776HgKLEGSs7unW7GT82AgfMbQX5crfSybGU8b",
       "name": "go-ipfs-ds-help",
-      "version": "0.0.10"
+      "version": "0.1.0"
     },
     {
       "author": "kubuxu",
@@ -60,6 +60,6 @@
   "license": "MIT",
   "name": "go-ipfs-blockstore",
   "releaseCmd": "git commit -a -m \"gx publish $VERSION\"",
-  "version": "0.0.20"
+  "version": "0.1.0"
 }