diff --git a/src/hashtree.py b/src/hashtree.py
--- a/src/hashtree.py
+++ b/src/hashtree.py
@@ -4,60 +4,60 @@ import collections
 
 
 class HashTree:
-  HASH_LEN=16 # bytes
-  BLOCK_SIZE=4096 # bytes
-  
-  ## Prepares a tree containing leafCount leaves.
-  def __init__(self,leafCount):
-    self.store=[None]*(leafCount*2-1)
-    self.leafStart=leafCount-1
-    self.index=self.leafStart
-    self.leafCount=leafCount
-    
-  @classmethod
-  def fromFile(cls,fd):
-    stat=os.fstat(fd.fileno())
-    size=stat.st_size # !! symlinks
-    leafCount=(size-1)//HashTree.BLOCK_SIZE+1 # number of leaf blocks
-    res=cls(leafCount)
-    
-    for i in range(leafCount):
-      data=fd.read(HashTree.BLOCK_SIZE)
-      res.insertLeaf(hashlib.sha256(data).digest()[HashTree.HASH_LEN:])
-    res.buildTree()
-    
-    return res
-    
-    
-  ## Inserts a leaf at the first empty position.
-  #  
-  #  Useful and used only during the tree construction.
-  def insertLeaf(self,h):
-    self.store[self.index]=h
-    self.index+=1
-    
-  ## Updates a hash stored in the leaf.
-  def updateLeaf(self,index,h):
-    if index<self.leafStart: raise IndexError()
-    
-    self.store[index]=h
-    self.updateNode((index-1)//2)
-  
-  ## Updates the node at index and all its ancestors.
-  def updateNode(self,index):
-    while index>=0:
-      self.store[index]=hashlib.sha256(self.store[index*2+1]+self.store[index*2+2]).digest()[HashTree.HASH_LEN:]
-      index=(index-1)//2
-      
-  ## Fast construction of the tree over the leaves. O(n).
-  def buildTree(self):
-    for i in range(self.leafStart-1,-1,-1):
-      self.store[i]=hashlib.sha256(self.store[i*2+1]+self.store[i*2+2]).digest()[HashTree.HASH_LEN:]
+	HASH_LEN=16 # bytes
+	BLOCK_SIZE=4096 # bytes
+	
+	## Prepares a tree containing leafCount leaves.
+	def __init__(self,leafCount):
+		self.store=[None]*(leafCount*2-1)
+		self.leafStart=leafCount-1
+		self.index=self.leafStart
+		self.leafCount=leafCount
+		
+	@classmethod
+	def fromFile(cls,fd):
+		stat=os.fstat(fd.fileno())
+		size=stat.st_size # !! symlinks
+		leafCount=(size-1)//HashTree.BLOCK_SIZE+1 # number of leaf blocks
+		res=cls(leafCount)
+		
+		for i in range(leafCount):
+			data=fd.read(HashTree.BLOCK_SIZE)
+			res.insertLeaf(hashlib.sha256(data).digest()[HashTree.HASH_LEN:])
+		res.buildTree()
+		
+		return res
+		
+		
+	## Inserts a leaf at the first empty position.
+	#	
+	#	Useful and used only during the tree construction.
+	def insertLeaf(self,h):
+		self.store[self.index]=h
+		self.index+=1
+		
+	## Updates a hash stored in the leaf.
+	def updateLeaf(self,index,h):
+		if index<self.leafStart: raise IndexError()
+		
+		self.store[index]=h
+		self.updateNode((index-1)//2)
+	
+	## Updates the node at index and all its ancestors.
+	def updateNode(self,index):
+		while index>=0:
+			self.store[index]=hashlib.sha256(self.store[index*2+1]+self.store[index*2+2]).digest()[HashTree.HASH_LEN:]
+			index=(index-1)//2
+			
+	## Fast construction of the tree over the leaves. O(n).
+	def buildTree(self):
+		for i in range(self.leafStart-1,-1,-1):
+			self.store[i]=hashlib.sha256(self.store[i*2+1]+self.store[i*2+2]).digest()[HashTree.HASH_LEN:]
 
 
 if __name__=="__main__":
-  f1=HashTree.fromFile(open("serverFile.txt",mode='rb'))
-  f2=HashTree.fromFile(open("clientFile.txt",mode='rb'))
+	f1=HashTree.fromFile(open("serverFile.txt",mode='rb'))
+	f2=HashTree.fromFile(open("clientFile.txt",mode='rb'))
 
-  for i,(h1,h2) in enumerate(zip(f1.store,f2.store)):
-    print("{0:2}".format(i),h1.hex(),h2.hex(),h1==h2)
+	for i,(h1,h2) in enumerate(zip(f1.store,f2.store)):
+		print("{0:2}".format(i),h1.hex(),h2.hex(),h1==h2)