diff --git a/src/client.py b/src/client.py
--- a/src/client.py
+++ b/src/client.py
@@ -2,6 +2,7 @@
 import collections
 import socket
 import sys
+import logging as log
 
 import config as conf
 from networkers import NetworkReader,NetworkWriter
@@ -57,7 +58,7 @@ def negotiate():
 
 
 def sendData(blocksToTransfer):
-	print(blocksToTransfer)
+	log.info(blocksToTransfer)
 	dataFile=open(filename,mode="rb")
 	i1=-1
 
@@ -68,7 +69,7 @@ def sendData(blocksToTransfer):
 				dataFile.seek(i2*HashTree.BLOCK_SIZE)
 			binData=dataFile.read(HashTree.BLOCK_SIZE)
 
-			print("block #{0}: {1}...{2}".format(i2,binData[:5],binData[-5:]))
+			log.info("block #{0}: {1}...{2}".format(i2,binData[:5],binData[-5:]))
 
 			outcoming.writeMsg(jsonData,binData)
 			i1=i2
@@ -76,7 +77,7 @@ def sendData(blocksToTransfer):
 	with Connection() as (incoming,outcoming):
 		outcoming.writeMsg({"command":"end"})
 
-	print("closing...")
+	log.info("closing session...")
 	dataFile.close()
 
 
diff --git a/src/config.py b/src/config.py
--- a/src/config.py
+++ b/src/config.py
@@ -1,3 +1,8 @@
+import logging as log
+
+
+log.basicConfig(level=log.INFO,format="%(asctime)s %(levelname)s: %(message)s",datefmt="%Y-%m-%d %H:%M:%S")
+
 version=0
 
 hosts=["127.0.0.1"]
diff --git a/src/server.py b/src/server.py
--- a/src/server.py
+++ b/src/server.py
@@ -3,9 +3,11 @@ from hashtree import HashTree
 from networkers import NetworkReader,NetworkWriter
 import collections
 import sys
+import logging as log
 
 import config as conf
 
+
 # debug copy default file
 import shutil
 origFilename=sys.argv[1]
@@ -16,7 +18,7 @@ shutil.copyfile(origFilename,filename)
 class Connection:
 	def __init__(self,server_socket):
 		self.socket, address = server_socket.accept()
-		print('Connected by', address)
+		log.info('Connected by {0}'.format(address))
 		fr=self.socket.makefile(mode="rb")
 		fw=self.socket.makefile(mode="wb")
 
@@ -52,7 +54,7 @@ while True:
 			assert jsonData["blockCount"]==localTree.leafCount
 
 		elif jsonData["command"]=="req": # !! index out of range
-			print("received request for node #{0}".format(jsonData["index"]))
+			log.info("received request for node #{0}".format(jsonData["index"]))
 			nodeHash=localTree.store[jsonData["index"]]
 
 			jsonResponse={"command":"send", "index":jsonData["index"], "dataType":"hash"}
@@ -61,7 +63,7 @@ while True:
 			outcoming.writeMsg(jsonResponse,binResponse)
 
 		elif jsonData["command"]=="send" and jsonData["dataType"]=="data": # needlessly allow hashes and data in mixed order
-			print("received data block #{0}: {1}...{2}".format(jsonData["index"],binData[:5],binData[-5:]))
+			log.info("received data block #{0}: {1}...{2}".format(jsonData["index"],binData[:5],binData[-5:]))
 
 			i2=jsonData["index"]
 			if i1+1!=i2:
@@ -72,7 +74,7 @@ while True:
 			# never update the hash tree
 
 		elif jsonData["command"]=="end":
-			print("closing...")
+			log.info("closing session...")
 			break
 	
 		else: pass # !! error