diff --git a/sharding/collation.go b/sharding/collation.go
index ceff9e6f8..1b9e9a890 100644
--- a/sharding/collation.go
+++ b/sharding/collation.go
@@ -122,9 +122,11 @@ func (c *Collation) CalculateChunkRoot() {
 // some salt, which is appended to each chunk in the collation body before it
 // is hashed.
 func (c *Collation) CalculatePOC(salt []byte) common.Hash {
-	body := make([]byte, len(c.body))
+	body := make([]byte, 0, len(c.body)*(1+len(salt)))
+
+	// TODO: Use 32 byte chunks instead of a single byte
 	for _, chunk := range c.body {
-		body = append(body, append(salt, chunk)...) // add salt to each chunk.
+		body = append(append(body, salt...), chunk)
 	}
 	if len(c.body) == 0 {
 		body = salt
@@ -139,23 +141,6 @@ func BytesToChunks(body []byte) Chunks {
 	return Chunks(body)
 }
 
-// ConvertBackToTx converts raw blobs back to their original transactions.
-func ConvertBackToTx(rawBlobs []utils.RawBlob) ([]*types.Transaction, error) {
-
-	blobs := make([]*types.Transaction, len(rawBlobs))
-
-	for i := 0; i < len(rawBlobs); i++ {
-
-		blobs[i] = types.NewTransaction(0, common.HexToAddress("0x"), nil, 0, nil, nil)
-
-		err := utils.ConvertFromRawBlob(&rawBlobs[i], blobs[i])
-		if err != nil {
-			return nil, fmt.Errorf("Creation of transactions from raw blobs failed: %v", err)
-		}
-	}
-	return blobs, nil
-}
-
 // convertTxToRawBlob transactions into RawBlobs. This step encodes transactions uses RLP encoding
 func convertTxToRawBlob(txs []*types.Transaction) ([]*utils.RawBlob, error) {
 	blobs := make([]*utils.RawBlob, len(txs))
diff --git a/sharding/collation_test.go b/sharding/collation_test.go
index 5d74907c0..a688bd5fe 100644
--- a/sharding/collation_test.go
+++ b/sharding/collation_test.go
@@ -308,3 +308,17 @@ func BenchmarkSerializeRoundtrip100(b *testing.B) {
 func BenchmarkSerializeRoundtrip1000(b *testing.B) {
 	runSerializeRoundtrip(b, 1000)
 }
+
+func BenchmarkCalculatePOC(b *testing.B) {
+	body := make([]byte, 300)
+	rand.Read(body)
+
+	collation := NewCollation(&CollationHeader{}, body, nil)
+
+	salt := make([]byte, 20)
+	rand.Read(salt)
+
+	for i := 0; i < b.N; i++ {
+		collation.CalculatePOC(salt)
+	}
+}