diff --git a/src/recipient/recipient.go b/src/recipient/recipient.go
index 5d283b2..12e618c 100644
--- a/src/recipient/recipient.go
+++ b/src/recipient/recipient.go
@@ -1,6 +1,7 @@
 package recipient
 
 import (
+	"bufio"
 	"bytes"
 	"encoding/json"
 	"errors"
@@ -50,8 +51,11 @@ func receive(forceSend int, serverAddress string, tcpPorts []string, isLocal boo
 	var transferTime time.Duration
 	var hash256 []byte
 	var otherIP string
+	var progressFile string
+	var resumeFile bool
 	var tcpConnections []comm.Comm
 	dataChan := make(chan []byte, 1024*1024)
+	blocks := []string{}
 
 	useWebsockets := true
 	switch forceSend {
@@ -129,6 +133,7 @@ func receive(forceSend int, serverAddress string, tcpPorts []string, isLocal boo
 				return err
 			}
 			log.Debugf("%x\n", sessionKey)
+
 			c.WriteMessage(websocket.BinaryMessage, []byte("ready"))
 		case 3:
 			spin.Stop()
@@ -151,9 +156,14 @@ func receive(forceSend int, serverAddress string, tcpPorts []string, isLocal boo
 			log.Debugf("got file stats: %+v", fstats)
 
 			// prompt user if its okay to receive file
+			progressFile = fmt.Sprintf("%s.progress", fstats.SentName)
 			overwritingOrReceiving := "Receiving"
-			if utils.Exists(fstats.Name) {
+			if utils.Exists(fstats.Name) || utils.Exists(fstats.SentName) {
 				overwritingOrReceiving = "Overwriting"
+				if utils.Exists(progressFile) {
+					overwritingOrReceiving = "Resume receiving"
+					resumeFile = true
+				}
 			}
 			fileOrFolder := "file"
 			if fstats.IsDir {
@@ -189,15 +199,50 @@ func receive(forceSend int, serverAddress string, tcpPorts []string, isLocal boo
 			}
 
 			// await file
-			f, err := os.Create(fstats.SentName)
-			if err != nil {
-				log.Error(err)
-				return err
+			var f *os.File
+			if utils.Exists(fstats.SentName) && resumeFile {
+				if !useWebsockets {
+					f, err = os.OpenFile(fstats.SentName, os.O_WRONLY, 0644)
+				} else {
+					f, err = os.OpenFile(fstats.SentName, os.O_APPEND, 0644)
+				}
+				if err != nil {
+					log.Error(err)
+					return err
+				}
+			} else {
+				f, err = os.Create(fstats.SentName)
+				if err != nil {
+					log.Error(err)
+					return err
+				}
+				if !useWebsockets {
+					if err = f.Truncate(fstats.Size); err != nil {
+						log.Error(err)
+						return err
+					}
+				}
 			}
-			if err = f.Truncate(fstats.Size); err != nil {
-				log.Error(err)
-				return err
+
+			// append the previous blocks if there was progress previously
+			if resumeFile {
+				file, _ := os.Open(progressFile)
+				scanner := bufio.NewScanner(file)
+				for scanner.Scan() {
+					blocks = append(blocks, strings.TrimSpace(scanner.Text()))
+				}
+				file.Close()
 			}
+			blocksBytes, _ := json.Marshal(blocks)
+
+			blockSize := 0
+			if useWebsockets {
+				blockSize = models.WEBSOCKET_BUFFER_SIZE / 8
+			} else {
+				blockSize = models.TCP_BUFFER_SIZE / 2
+			}
+
+			// start the ui for pgoress
 			bytesWritten := 0
 			fmt.Fprintf(os.Stderr, "\nReceiving (<-%s)...\n", otherIP)
 			bar := progressbar.NewOptions(
@@ -206,9 +251,32 @@ func receive(forceSend int, serverAddress string, tcpPorts []string, isLocal boo
 				progressbar.OptionSetBytes(int(fstats.Size)),
 				progressbar.OptionSetWriter(os.Stderr),
 			)
+			bar.Add((len(blocks) * blockSize))
 			finished := make(chan bool)
 
 			go func(finished chan bool, dataChan chan []byte) (err error) {
+				// remove previous progress
+				var fProgress *os.File
+				var progressErr error
+				if resumeFile {
+					fProgress, progressErr = os.OpenFile(progressFile, os.O_APPEND, 0644)
+					bytesWritten = len(blocks) * blockSize
+				} else {
+					os.Remove(progressFile)
+					fProgress, progressErr = os.Create(progressFile)
+				}
+				if progressErr != nil {
+					panic(progressErr)
+				}
+				defer fProgress.Close()
+
+				blocksWritten := 0.0
+				blocksToWrite := float64(fstats.Size)
+				if useWebsockets {
+					blocksToWrite = blocksToWrite/float64(models.WEBSOCKET_BUFFER_SIZE/8) - float64(len(blocks))
+				} else {
+					blocksToWrite = blocksToWrite/float64(models.TCP_BUFFER_SIZE/2) - float64(len(blocks))
+				}
 				for {
 					message := <-dataChan
 					// do decryption
@@ -245,19 +313,25 @@ func receive(forceSend int, serverAddress string, tcpPorts []string, isLocal boo
 							return err
 						}
 						n, err = f.WriteAt(decrypted, int64(locationToWrite))
+						fProgress.WriteString(fmt.Sprintf("%d\n", locationToWrite))
+						log.Debugf("writing to location %d (%2.0f/%2.0f)", locationToWrite, blocksWritten, blocksToWrite)
 					} else {
 						// write to file
 						n, err = f.Write(decrypted)
+						log.Debugf("writing to location %d (%2.0f/%2.0f)", bytesWritten, blocksWritten, blocksToWrite)
+						fProgress.WriteString(fmt.Sprintf("%d\n", bytesWritten))
 					}
 
 					if err != nil {
+						log.Error(err)
 						return err
 					}
 					// update the bytes written
 					bytesWritten += n
+					blocksWritten += 1.0
 					// update the progress bar
 					bar.Add(n)
-					if int64(bytesWritten) == fstats.Size {
+					if int64(bytesWritten) == fstats.Size || blocksWritten >= blocksToWrite {
 						log.Debug("finished")
 						break
 					}
@@ -267,7 +341,8 @@ func receive(forceSend int, serverAddress string, tcpPorts []string, isLocal boo
 			}(finished, dataChan)
 
 			log.Debug("telling sender i'm ready")
-			c.WriteMessage(websocket.BinaryMessage, []byte("ready"))
+			c.WriteMessage(websocket.BinaryMessage, append([]byte("ready"), blocksBytes...))
+
 			startTime := time.Now()
 			if useWebsockets {
 				for {
@@ -388,6 +463,7 @@ func receive(forceSend int, serverAddress string, tcpPorts []string, isLocal boo
 						fstats.Name = "stdout"
 					}
 					fmt.Fprintf(os.Stderr, "\nReceived %s written to %s (%2.1f %s)\n", folderOrFile, fstats.Name, transferRate, transferType)
+					os.Remove(progressFile)
 				}
 				return err
 			} else {
@@ -397,7 +473,6 @@ func receive(forceSend int, serverAddress string, tcpPorts []string, isLocal boo
 				}
 				return errors.New("file corrupted")
 			}
-
 		default:
 			return fmt.Errorf("unknown step")
 		}
diff --git a/src/sender/sender.go b/src/sender/sender.go
index caed83d..f386c41 100644
--- a/src/sender/sender.go
+++ b/src/sender/sender.go
@@ -8,6 +8,7 @@ import (
 	"net"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -52,6 +53,7 @@ func send(forceSend int, serverAddress string, tcpPorts []string, isLocal bool,
 	var otherIP string
 	var startTransfer time.Time
 	var tcpConnections []comm.Comm
+	blocksToSkip := make(map[int64]struct{})
 
 	type DataChan struct {
 		b                []byte
@@ -169,87 +171,6 @@ func send(forceSend int, serverAddress string, tcpPorts []string, isLocal bool,
 				}
 				fileReady <- nil
 
-				// start streaming encryption/compression
-				go func(dataChan chan DataChan) {
-					var buffer []byte
-					if useWebsockets {
-						buffer = make([]byte, models.WEBSOCKET_BUFFER_SIZE/8)
-					} else {
-						buffer = make([]byte, models.TCP_BUFFER_SIZE/2)
-					}
-					currentPostition := int64(0)
-					for {
-						bytesread, err := f.Read(buffer)
-						if bytesread > 0 {
-							// do compression
-							var compressedBytes []byte
-							if useCompression && !fstats.IsDir {
-								compressedBytes = compress.Compress(buffer[:bytesread])
-							} else {
-								compressedBytes = buffer[:bytesread]
-							}
-
-							// if using TCP, prepend the location to write the data to in the resulting file
-							if !useWebsockets {
-								compressedBytes = append([]byte(fmt.Sprintf("%d-", currentPostition)), compressedBytes...)
-							}
-
-							// do encryption
-							enc := crypt.Encrypt(compressedBytes, sessionKey, !useEncryption)
-							encBytes, err := json.Marshal(enc)
-							if err != nil {
-								dataChan <- DataChan{
-									b:         nil,
-									bytesRead: 0,
-									err:       err,
-								}
-								return
-							}
-
-							select {
-							case dataChan <- DataChan{
-								b:         encBytes,
-								bytesRead: bytesread,
-								err:       nil,
-							}:
-							default:
-								log.Debug("blocked")
-								// no message sent
-								// block
-								dataChan <- DataChan{
-									b:         encBytes,
-									bytesRead: bytesread,
-									err:       nil,
-								}
-							}
-							currentPostition += int64(bytesread)
-						}
-						if err != nil {
-							if err != io.EOF {
-								log.Error(err)
-							}
-							break
-						}
-					}
-					// finish
-					log.Debug("sending magic")
-					dataChan <- DataChan{
-						b:         []byte("magic"),
-						bytesRead: 0,
-						err:       nil,
-					}
-					if !useWebsockets {
-						log.Debug("sending extra magic to %d others", len(tcpPorts)-1)
-						for i := 0; i < len(tcpPorts)-1; i++ {
-							log.Debug("sending magic")
-							dataChan <- DataChan{
-								b:         []byte("magic"),
-								bytesRead: 0,
-								err:       nil,
-							}
-						}
-					}
-				}(dataChan)
 			}()
 
 			// send pake data
@@ -275,9 +196,10 @@ func send(forceSend int, serverAddress string, tcpPorts []string, isLocal bool,
 			spin.Start()
 		case 3:
 			log.Debugf("[%d] recipient declares readiness for file info", step)
-			if !bytes.Equal(message, []byte("ready")) {
+			if !bytes.HasPrefix(message, []byte("ready")) {
 				return errors.New("recipient refused file")
 			}
+
 			err = <-fileReady // block until file is ready
 			if err != nil {
 				return err
@@ -295,10 +217,111 @@ func send(forceSend int, serverAddress string, tcpPorts []string, isLocal bool,
 			spin.Stop()
 
 			log.Debugf("[%d] recipient declares readiness for file data", step)
-			if !bytes.Equal(message, []byte("ready")) {
+			if !bytes.HasPrefix(message, []byte("ready")) {
 				return errors.New("recipient refused file")
 			}
 
+			// determine if any blocks were sent to skip
+			var blocks []string
+			errBlocks := json.Unmarshal(message[5:], &blocks)
+			if errBlocks == nil {
+				for _, block := range blocks {
+					blockInt64, errBlock := strconv.Atoi(block)
+					if errBlock == nil {
+						blocksToSkip[int64(blockInt64)] = struct{}{}
+					}
+				}
+			}
+			log.Debugf("found blocks: %+v", blocksToSkip)
+
+			// start streaming encryption/compression
+			go func(dataChan chan DataChan) {
+				var buffer []byte
+				if useWebsockets {
+					buffer = make([]byte, models.WEBSOCKET_BUFFER_SIZE/8)
+				} else {
+					buffer = make([]byte, models.TCP_BUFFER_SIZE/2)
+				}
+				currentPostition := int64(0)
+				for {
+					bytesread, err := f.Read(buffer)
+					if bytesread > 0 {
+						if _, ok := blocksToSkip[currentPostition]; ok {
+							log.Debugf("skipping the sending of block %d", currentPostition)
+							currentPostition += int64(bytesread)
+							continue
+						}
+
+						// do compression
+						var compressedBytes []byte
+						if useCompression && !fstats.IsDir {
+							compressedBytes = compress.Compress(buffer[:bytesread])
+						} else {
+							compressedBytes = buffer[:bytesread]
+						}
+
+						// if using TCP, prepend the location to write the data to in the resulting file
+						if !useWebsockets {
+							compressedBytes = append([]byte(fmt.Sprintf("%d-", currentPostition)), compressedBytes...)
+						}
+
+						// do encryption
+						enc := crypt.Encrypt(compressedBytes, sessionKey, !useEncryption)
+						encBytes, err := json.Marshal(enc)
+						if err != nil {
+							dataChan <- DataChan{
+								b:         nil,
+								bytesRead: 0,
+								err:       err,
+							}
+							return
+						}
+
+						select {
+						case dataChan <- DataChan{
+							b:         encBytes,
+							bytesRead: bytesread,
+							err:       nil,
+						}:
+						default:
+							log.Debug("blocked")
+							// no message sent
+							// block
+							dataChan <- DataChan{
+								b:         encBytes,
+								bytesRead: bytesread,
+								err:       nil,
+							}
+						}
+						currentPostition += int64(bytesread)
+					}
+					if err != nil {
+						if err != io.EOF {
+							log.Error(err)
+						}
+						break
+					}
+				}
+				// finish
+				log.Debug("sending magic")
+				dataChan <- DataChan{
+					b:         []byte("magic"),
+					bytesRead: 0,
+					err:       nil,
+				}
+				if !useWebsockets {
+					log.Debug("sending extra magic to %d others", len(tcpPorts)-1)
+					for i := 0; i < len(tcpPorts)-1; i++ {
+						log.Debug("sending magic")
+						dataChan <- DataChan{
+							b:         []byte("magic"),
+							bytesRead: 0,
+							err:       nil,
+						}
+					}
+				}
+			}(dataChan)
+
 			// connect to TCP to receive file
 			if !useWebsockets {
 				log.Debugf("connecting to server")
@@ -318,12 +341,19 @@ func send(forceSend int, serverAddress string, tcpPorts []string, isLocal bool,
 			// send file, compure hash simultaneously
 			startTransfer = time.Now()
 
+			blockSize := 0
+			if useWebsockets {
+				blockSize = models.WEBSOCKET_BUFFER_SIZE / 8
+			} else {
+				blockSize = models.TCP_BUFFER_SIZE / 2
+			}
 			bar := progressbar.NewOptions(
 				int(fstats.Size),
 				progressbar.OptionSetRenderBlankState(true),
 				progressbar.OptionSetBytes(int(fstats.Size)),
 				progressbar.OptionSetWriter(os.Stderr),
 			)
+			bar.Add(blockSize * len(blocksToSkip))
 
 			if useWebsockets {
 				for {
diff --git a/src/zipper/zip.go b/src/zipper/zip.go
index faffbd7..bfea9df 100644
--- a/src/zipper/zip.go
+++ b/src/zipper/zip.go
@@ -4,7 +4,6 @@ import (
 	"archive/zip"
 	"compress/flate"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -97,7 +96,7 @@ func ZipFile(fname string, compress bool) (writtenFilename string, err error) {
 		return
 	}
 	log.Debugf("current directory: %s", curdir)
-	newfile, err := ioutil.TempFile(curdir, filename+".")
+	newfile, err := os.Create(fname + ".croc.zip")
 	if err != nil {
 		log.Error(err)
 		return