Fix/reduce encryption header size (#538)

* fix(download): reduced EncryptionHeaderSize with 257

* fix(download): reduced EncryptionHeaderSize with 256

Author: cnlangzi

code/go/0chain.net/blobbercore/handler/chunk_encoder.go

@@ -3,7 +3,6 @@ package handler
 import (
 	"bytes"
 	"errors"
-	"strings"
 
 	zencryption "github.com/0chain/gosdk/zboxcore/encryption"
 )
@@ -62,14 +61,12 @@ func (r *PREChunkEncoder) Encode(chunkSize int, data []byte) ([]byte, error) {
 
 		headerBytes := chunkData[:EncryptionHeaderSize]
 		headerBytes = bytes.Trim(headerBytes, "\x00")
-		headerString := string(headerBytes)
 
-		headerChecksums := strings.Split(headerString, ",")
-		if len(headerChecksums) != 2 {
+		if len(headerBytes) != EncryptionHeaderSize {
 			return nil, errors.New("Block has invalid encryption header")
 		}
 
-		encMsg.MessageChecksum, encMsg.OverallChecksum = headerChecksums[0], headerChecksums[1]
+		encMsg.MessageChecksum, encMsg.OverallChecksum = string(headerBytes[:128]), string(headerBytes[128:])
 		encMsg.EncryptedKey = encscheme.GetEncryptedKey()
 
 		reEncMsg, err := encscheme.ReEncrypt(encMsg, r.ReEncryptionKey, r.ClientEncryptionPublicKey)

code/go/0chain.net/blobbercore/handler/handler_test.go

@@ -1877,7 +1877,7 @@ func TestHandlers_Requiring_Signature(t *testing.T) {
 				}
 
 				header := make([]byte, EncryptionHeaderSize)
-				copy(header, encMsg.MessageChecksum+","+encMsg.OverallChecksum)
+				copy(header, encMsg.MessageChecksum+encMsg.OverallChecksum)
 				data := append(header, encMsg.EncryptedData...)
 				fmt.Println("Encrypted data: ", string(data))
 				setMockFileBlock(data)
@@ -2029,7 +2029,7 @@ func TestHandlers_Requiring_Signature(t *testing.T) {
 				}
 
 				header := make([]byte, EncryptionHeaderSize)
-				copy(header, encMsg.MessageChecksum+","+encMsg.OverallChecksum)
+				copy(header, encMsg.MessageChecksum+encMsg.OverallChecksum)
 				data := append(header, encMsg.EncryptedData...)
 				setMockFileBlock(data)
 			},
@@ -2184,7 +2184,7 @@ func TestHandlers_Requiring_Signature(t *testing.T) {
 				}
 
 				header := make([]byte, EncryptionHeaderSize)
-				copy(header, encMsg.MessageChecksum+","+encMsg.OverallChecksum)
+				copy(header, encMsg.MessageChecksum+encMsg.OverallChecksum)
 				data := append(header, encMsg.EncryptedData...)
 				setMockFileBlock(data)
 			},
@@ -2339,7 +2339,7 @@ func TestHandlers_Requiring_Signature(t *testing.T) {
 				}
 
 				header := make([]byte, EncryptionHeaderSize)
-				copy(header, encMsg.MessageChecksum+","+encMsg.OverallChecksum)
+				copy(header, encMsg.MessageChecksum+encMsg.OverallChecksum)
 				data := append(header, encMsg.EncryptedData...)
 				setMockFileBlock(data)
 			},

code/go/0chain.net/blobbercore/handler/object_operation_handler.go

@@ -34,8 +34,8 @@ import (
 )
 
 const (
-	// EncryptionHeaderSize encryption header size in chunk
-	EncryptionHeaderSize = 2 * 1024
+	// EncryptionHeaderSize encryption header size in chunk: PRE.MessageChecksum(128)"+PRE.OverallChecksum(128)
+	EncryptionHeaderSize = 128 + 128
 	// ReEncryptionHeaderSize re-encryption header size in chunk
 	ReEncryptionHeaderSize = 256
 )