X-Git-Url: http://wagner.pp.ru/gitweb/?a=blobdiff_plain;f=ctypescrypto%2Fcipher.py;h=815a42541897232853a0721b9fea12be9d42217b;hb=ca6a5055ad8a9ea82e9f42aff3c906903d5e6df7;hp=1ea4f797d7f4d87e88e86832ae438651d18dde68;hpb=8afcf4f352ef2f967adbe84837d4abc5e9b6ee0c;p=oss%2Fctypescrypto.git

diff --git a/ctypescrypto/cipher.py b/ctypescrypto/cipher.py
index 1ea4f79..815a425 100644
--- a/ctypescrypto/cipher.py
+++ b/ctypescrypto/cipher.py
@@ -1,3 +1,7 @@
+"""
+access to symmetric ciphers from libcrypto
+
+"""
 from ctypes import create_string_buffer,c_char_p,c_void_p,c_int,c_long,byref,POINTER
 from ctypescrypto import libcrypto
 from ctypescrypto.exception import LibCryptoError
@@ -8,6 +12,8 @@ CIPHER_MODES = ("STREAM","ECB","CBC", "CFB", "OFB", "CTR","GCM")
 
 #
 
+__all__ = ['CipherError','new','Cipher','CipherType']
+
 class CipherError(LibCryptoError):
 	pass
 
@@ -38,7 +44,7 @@ class CipherType:
 		"""
 		self.cipher = libcrypto.EVP_get_cipherbyname(cipher_name)
 		if self.cipher is None:
-			raise CipherError, "Unknown cipher: %s" % cipher_name
+			raise CipherError("Unknown cipher: %s" % cipher_name)
 
 	def __del__(self):
 		pass
@@ -101,20 +107,39 @@ class Cipher:
 
 		"""
 		self._clean_ctx()
+		# Check key and iv length
+		if key is None:
+			raise ValueError("No key specified")
+
 		key_ptr = c_char_p(key)
 		iv_ptr = c_char_p(iv)
 		self.ctx = libcrypto.EVP_CIPHER_CTX_new()
 		if self.ctx == 0:
-			raise CipherError, "Unable to create cipher context"
+			raise CipherError("Unable to create cipher context")
 		self.encrypt = encrypt
 		if encrypt: 
 			enc = 1
 		else: 
 			enc = 0
-		result = libcrypto.EVP_CipherInit_ex(self.ctx, cipher_type.cipher, None, key_ptr, iv_ptr, c_int(enc))
+		if not iv is None and len(iv) != cipher_type.iv_length():
+			raise ValueError("Invalid IV length for this algorithm")
+			
+		if len(key) != cipher_type.key_length():
+			if (cipher_type.flags() & 8) != 0:
+				# Variable key length cipher.
+				result = libcrypto.EVP_CipherInit_ex(self.ctx, cipher_type.cipher, None, None, None, c_int(enc))
+				result=libcrypto.EVP_CIPHER_CTX_set_key_length(self.ctx,len(key))
+				if result == 0:
+					self._clean_ctx()
+					raise CipherError("Unable to set key length")
+				result = libcrypto.EVP_CipherInit_ex(self.ctx, None, None, key_ptr, iv_ptr, c_int(enc))
+			else:
+				raise ValueError("Invalid key length for this algorithm")
+		else:
+			result = libcrypto.EVP_CipherInit_ex(self.ctx, cipher_type.cipher, None, key_ptr, iv_ptr, c_int(enc))
 		if result == 0:
 			self._clean_ctx()
-			raise CipherError, "Unable to initialize cipher"
+			raise CipherError("Unable to initialize cipher")
 		self.cipher_type = cipher_type
 		self.block_size = self.cipher_type.block_size()
 		self.cipher_finalized = False
@@ -145,9 +170,9 @@ class Cipher:
 			called
 		"""
 		if self.cipher_finalized :
-			raise CipherError, "No updates allowed"
-		if type(data) != type(""):
-			raise TypeError, "A string is expected"
+			raise CipherError("No updates allowed")
+		if not isinstance(data,str):
+			raise TypeError("A string is expected")
 		if len(data) <= 0:
 			return ""
 		outbuf=create_string_buffer(self.block_size+len(data))
@@ -167,14 +192,14 @@ class Cipher:
 			state, they would be processed and returned.
 		"""
 		if self.cipher_finalized :
-			raise CipherError, "Cipher operation is already completed"
+			raise CipherError("Cipher operation is already completed")
 		outbuf=create_string_buffer(self.block_size)
 		self.cipher_finalized = True
-		outlen=c_int()
+		outlen=c_int(0)
 		result = libcrypto.EVP_CipherFinal_ex(self.ctx,outbuf , byref(outlen))
 		if result == 0:
 			self._clean_ctx()
-			raise CipherError, "Unable to finalize cipher"
+			raise CipherError("Unable to finalize cipher")
 		if outlen.value>0:
 			return outbuf.raw[:outlen.value]
 		else:
@@ -208,4 +233,4 @@ libcrypto.EVP_CIPHER_nid.argtypes=(c_void_p,)
 libcrypto.EVP_CipherUpdate.argtypes=(c_void_p,c_char_p,POINTER(c_int),c_char_p,c_int)
 libcrypto.EVP_get_cipherbyname.restype=c_void_p
 libcrypto.EVP_get_cipherbyname.argtypes=(c_char_p,)
-
+libcrypto.EVP_CIPHER_CTX_set_key_length.argtypes=(c_void_p,c_int)