opcua.crypto.SecurityPolicyBasic256.encrypt_asymmetric() - Code Metrics - Inspection of "Use correct password encryption algorithm in clien..." - FreeOpcUa/python-opcua - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#128)

by Alexander

created 2016-02-01 17:27 UTC

encrypt_asymmetric() A

↳ Parent: opcua.crypto.SecurityPolicyBasic256

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	1
CRAP Score	1.125

Metric	Value
cc	1
dl	0
loc	3
ccs	1
cts	2
cp	0.5
crap	1.125
rs	10

from abc import ABCMeta, abstractmethod
from opcua.ua import CryptographyNone, SecurityPolicy
from opcua.ua import MessageSecurityMode
from opcua.ua import UaError
try:
    from opcua.crypto import uacrypto
    CRYPTOGRAPHY_AVAILABLE = True
except ImportError:
    CRYPTOGRAPHY_AVAILABLE = False


def require_cryptography(obj):
    """
    Raise exception if cryptography module is not available.
    Call this function in constructors.
    """
    if not CRYPTOGRAPHY_AVAILABLE:
        raise UaError("Can't use {}, cryptography module is not installed".format(obj.__class__.__name__))


class Signer(object):
    """
    Abstract base class for cryptographic signature algorithm
    """

    __metaclass__ = ABCMeta

    @abstractmethod
    def signature_size(self):
        pass

    @abstractmethod
    def signature(self, data):
        pass


class Verifier(object):
    """
    Abstract base class for cryptographic signature verification
    """

    __metaclass__ = ABCMeta

    @abstractmethod
    def signature_size(self):
        pass

    @abstractmethod
    def verify(self, data, signature):
        pass


class Encryptor(object):
    """
    Abstract base class for encryption algorithm
    """

    __metaclass__ = ABCMeta

    @abstractmethod
    def plain_block_size(self):
        pass

    @abstractmethod
    def encrypted_block_size(self):
        pass

    @abstractmethod
    def encrypt(self, data):
        pass


class Decryptor(object):
    """
    Abstract base class for decryption algorithm
    """

    __metaclass__ = ABCMeta

    @abstractmethod
    def plain_block_size(self):
        pass

    @abstractmethod
    def encrypted_block_size(self):
        pass

    @abstractmethod
    def decrypt(self, data):
        pass


class Cryptography(CryptographyNone):
    """
    Security policy: Sign or SignAndEncrypt
    """

    def __init__(self, mode=MessageSecurityMode.Sign):
        self.Signer = None
        self.Verifier = None
        self.Encryptor = None
        self.Decryptor = None
        assert mode in (MessageSecurityMode.Sign,
                        MessageSecurityMode.SignAndEncrypt)
        self.is_encrypted = (mode == MessageSecurityMode.SignAndEncrypt)

    def plain_block_size(self):
        """
        Size of plain text block for block cipher.
        """
        if self.is_encrypted:
            return self.Encryptor.plain_block_size()
        return 1

    def encrypted_block_size(self):
        """
        Size of encrypted text block for block cipher.
        """
        if self.is_encrypted:
            return self.Encryptor.encrypted_block_size()
        return 1

    def padding(self, size):
        """
        Create padding for a block of given size.
        plain_size = size + len(padding) + signature_size()
        plain_size = N * plain_block_size()
        """
        if not self.is_encrypted:
            return b''
        block_size = self.Encryptor.plain_block_size()
        rem = (size + self.signature_size() + 1) % block_size
        if rem != 0:
            rem = block_size - rem
        return bytes(bytearray([rem])) * (rem + 1)

    def min_padding_size(self):
        if self.is_encrypted:
            return 1
        return 0

    def signature_size(self):
        return self.Signer.signature_size()

    def signature(self, data):
        return self.Signer.signature(data)

    def vsignature_size(self):
        return self.Verifier.signature_size()

    def verify(self, data, sig):
        self.Verifier.verify(data, sig)

    def encrypt(self, data):
        if self.is_encrypted:
            assert len(data) % self.Encryptor.plain_block_size() == 0
            return self.Encryptor.encrypt(data)
        return data

    def decrypt(self, data):
        if self.is_encrypted:
            return self.Decryptor.decrypt(data)
        return data

    def remove_padding(self, data):
        if self.is_encrypted:
            pad_size = bytearray(data[-1:])[0] + 1
            return data[:-pad_size]
        return data


class SignerRsa(Signer):

    def __init__(self, client_pk):
        require_cryptography(self)
        self.client_pk = client_pk
        self.key_size = self.client_pk.key_size // 8

    def signature_size(self):
        return self.key_size

    def signature(self, data):
        return uacrypto.sign_sha1(self.client_pk, data)


class VerifierRsa(Verifier):

    def __init__(self, server_cert):
        require_cryptography(self)
        self.server_cert = server_cert
        self.key_size = self.server_cert.public_key().key_size // 8

    def signature_size(self):
        return self.key_size

    def verify(self, data, signature):
        uacrypto.verify_sha1(self.server_cert, data, signature)


class EncryptorRsa(Encryptor):

    def __init__(self, server_cert, enc_fn, padding_size):
        require_cryptography(self)
        self.server_cert = server_cert
        self.key_size = self.server_cert.public_key().key_size // 8
        self.encryptor = enc_fn
        self.padding_size = padding_size

    def plain_block_size(self):
        return self.key_size - self.padding_size

    def encrypted_block_size(self):
        return self.key_size

    def encrypt(self, data):
        encrypted = b''
        block_size = self.plain_block_size()
        for i in range(0, len(data), block_size):
            encrypted += self.encryptor(self.server_cert.public_key(),
                                        data[i: i + block_size])
        return encrypted


class DecryptorRsa(Decryptor):

    def __init__(self, client_pk, dec_fn, padding_size):
        require_cryptography(self)
        self.client_pk = client_pk
        self.key_size = self.client_pk.key_size // 8
        self.decryptor = dec_fn
        self.padding_size = padding_size

    def plain_block_size(self):
        return self.key_size - self.padding_size

    def encrypted_block_size(self):
        return self.key_size

    def decrypt(self, data):
        decrypted = b''
        block_size = self.encrypted_block_size()
        for i in range(0, len(data), block_size):
            decrypted += self.decryptor(self.client_pk,
                                        data[i: i + block_size])
        return decrypted


class SignerAesCbc(Signer):

    def __init__(self, key):
        require_cryptography(self)
        self.key = key

    def signature_size(self):
        return uacrypto.sha1_size()

    def signature(self, data):
        return uacrypto.hmac_sha1(self.key, data)


class VerifierAesCbc(Verifier):

    def __init__(self, key):
        require_cryptography(self)
        self.key = key

    def signature_size(self):
        return uacrypto.sha1_size()

    def verify(self, data, signature):
        expected = uacrypto.hmac_sha1(self.key, data)
        if signature != expected:
            raise uacrypto.InvalidSignature


class EncryptorAesCbc(Encryptor):

    def __init__(self, key, init_vec):
        require_cryptography(self)
        self.cipher = uacrypto.cipher_aes_cbc(key, init_vec)

    def plain_block_size(self):
        return self.cipher.algorithm.key_size // 8

    def encrypted_block_size(self):
        return self.cipher.algorithm.key_size // 8

    def encrypt(self, data):
        return uacrypto.cipher_encrypt(self.cipher, data)


class DecryptorAesCbc(Decryptor):

    def __init__(self, key, init_vec):
        require_cryptography(self)
        self.cipher = uacrypto.cipher_aes_cbc(key, init_vec)

    def plain_block_size(self):
        return self.cipher.algorithm.key_size // 8

    def encrypted_block_size(self):
        return self.cipher.algorithm.key_size // 8

    def decrypt(self, data):
        return uacrypto.cipher_decrypt(self.cipher, data)


class SecurityPolicyBasic128Rsa15(SecurityPolicy):
    """
    Security Basic 128Rsa15
    A suite of algorithms that uses RSA15 as Key-Wrap-algorithm
    and 128-Bit (16 bytes) for encryption algorithms.
    - SymmetricSignatureAlgorithm - HmacSha1
      (http://www.w3.org/2000/09/xmldsig#hmac-sha1)
    - SymmetricEncryptionAlgorithm - Aes128
      (http://www.w3.org/2001/04/xmlenc#aes128-cbc)
    - AsymmetricSignatureAlgorithm - RsaSha1
      (http://www.w3.org/2000/09/xmldsig#rsa-sha1)
    - AsymmetricKeyWrapAlgorithm - KwRsa15
      (http://www.w3.org/2001/04/xmlenc#rsa-1_5)
    - AsymmetricEncryptionAlgorithm - Rsa15
      (http://www.w3.org/2001/04/xmlenc#rsa-1_5)
    - KeyDerivationAlgorithm - PSha1
      (http://docs.oasis-open.org/ws-sx/ws-secureconversation/200512/dk/p_sha1)
    - DerivedSignatureKeyLength - 128 (16 bytes)
    - MinAsymmetricKeyLength - 1024 (128 bytes)
    - MaxAsymmetricKeyLength - 2048 (256 bytes)
    - CertificateSignatureAlgorithm - Sha1

    If a certificate or any certificate in the chain is not signed with
    a hash that is Sha1 or stronger then the certificate shall be rejected.
    """

    URI = "http://opcfoundation.org/UA/SecurityPolicy#Basic128Rsa15"
    signature_key_size = 16
    symmetric_key_size = 16
    AsymmetricEncryptionURI = "http://www.w3.org/2001/04/xmlenc#rsa-1_5"

    @staticmethod
    def encrypt_asymmetric(pubkey, data):
        return uacrypto.encrypt_rsa15(pubkey, data)

    def __init__(self, server_cert, client_cert, client_pk, mode):
        require_cryptography(self)
        if isinstance(server_cert, bytes):
            server_cert = uacrypto.x509_from_der(server_cert)
        # even in Sign mode we need to asymmetrically encrypt secrets
        # transmitted in OpenSecureChannel. So SignAndEncrypt here
        self.asymmetric_cryptography = Cryptography(
            MessageSecurityMode.SignAndEncrypt)
        self.asymmetric_cryptography.Signer = SignerRsa(client_pk)
        self.asymmetric_cryptography.Verifier = VerifierRsa(server_cert)
        self.asymmetric_cryptography.Encryptor = EncryptorRsa(
            server_cert, uacrypto.encrypt_rsa15, 11)
        self.asymmetric_cryptography.Decryptor = DecryptorRsa(
            client_pk, uacrypto.decrypt_rsa15, 11)
        self.symmetric_cryptography = Cryptography(mode)
        self.Mode = mode
        self.server_certificate = uacrypto.der_from_x509(server_cert)
        self.client_certificate = uacrypto.der_from_x509(client_cert)

    def make_symmetric_key(self, nonce1, nonce2):
        key_sizes = (self.signature_key_size, self.symmetric_key_size, 16)

        (sigkey, key, init_vec) = uacrypto.p_sha1(nonce2, nonce1, key_sizes)
        self.symmetric_cryptography.Signer = SignerAesCbc(sigkey)
        self.symmetric_cryptography.Encryptor = EncryptorAesCbc(key, init_vec)

        (sigkey, key, init_vec) = uacrypto.p_sha1(nonce1, nonce2, key_sizes)
        self.symmetric_cryptography.Verifier = VerifierAesCbc(sigkey)
        self.symmetric_cryptography.Decryptor = DecryptorAesCbc(key, init_vec)


class SecurityPolicyBasic256(SecurityPolicy):
    """
    Security Basic 256
    A suite of algorithms that are for 256-Bit (32 bytes) encryption,
    algorithms include:
    - SymmetricSignatureAlgorithm - HmacSha1
      (http://www.w3.org/2000/09/xmldsig#hmac-sha1)
    - SymmetricEncryptionAlgorithm - Aes256
      (http://www.w3.org/2001/04/xmlenc#aes256-cbc)
    - AsymmetricSignatureAlgorithm - RsaSha1
      (http://www.w3.org/2000/09/xmldsig#rsa-sha1)
    - AsymmetricKeyWrapAlgorithm - KwRsaOaep
      (http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p)
    - AsymmetricEncryptionAlgorithm - RsaOaep
      (http://www.w3.org/2001/04/xmlenc#rsa-oaep)
    - KeyDerivationAlgorithm - PSha1
      (http://docs.oasis-open.org/ws-sx/ws-secureconversation/200512/dk/p_sha1)
    - DerivedSignatureKeyLength - 192 (24 bytes)
    - MinAsymmetricKeyLength - 1024 (128 bytes)
    - MaxAsymmetricKeyLength - 2048 (256 bytes)
    - CertificateSignatureAlgorithm - Sha1

    If a certificate or any certificate in the chain is not signed with
    a hash that is Sha1 or stronger then the certificate shall be rejected.
    """

    URI = "http://opcfoundation.org/UA/SecurityPolicy#Basic256"
    signature_key_size = 24
    symmetric_key_size = 32
    AsymmetricEncryptionURI = "http://www.w3.org/2001/04/xmlenc#rsa-oaep"

    @staticmethod
    def encrypt_asymmetric(pubkey, data):
        return uacrypto.encrypt_rsa_oaep(pubkey, data)

    def __init__(self, server_cert, client_cert, client_pk, mode):
        require_cryptography(self)
        if isinstance(server_cert, bytes):
            server_cert = uacrypto.x509_from_der(server_cert)
        # even in Sign mode we need to asymmetrically encrypt secrets
        # transmitted in OpenSecureChannel. So SignAndEncrypt here
        self.asymmetric_cryptography = Cryptography(
            MessageSecurityMode.SignAndEncrypt)
        self.asymmetric_cryptography.Signer = SignerRsa(client_pk)
        self.asymmetric_cryptography.Verifier = VerifierRsa(server_cert)
        self.asymmetric_cryptography.Encryptor = EncryptorRsa(
            server_cert, uacrypto.encrypt_rsa_oaep, 42)
        self.asymmetric_cryptography.Decryptor = DecryptorRsa(
            client_pk, uacrypto.decrypt_rsa_oaep, 42)
        self.symmetric_cryptography = Cryptography(mode)
        self.Mode = mode
        self.server_certificate = uacrypto.der_from_x509(server_cert)
        self.client_certificate = uacrypto.der_from_x509(client_cert)

    def make_symmetric_key(self, nonce1, nonce2):
        # specs part 6, 6.7.5
        key_sizes = (self.signature_key_size, self.symmetric_key_size, 16)

        (sigkey, key, init_vec) = uacrypto.p_sha1(nonce2, nonce1, key_sizes)
        self.symmetric_cryptography.Signer = SignerAesCbc(sigkey)
        self.symmetric_cryptography.Encryptor = EncryptorAesCbc(key, init_vec)

        (sigkey, key, init_vec) = uacrypto.p_sha1(nonce1, nonce2, key_sizes)
        self.symmetric_cryptography.Verifier = VerifierAesCbc(sigkey)
        self.symmetric_cryptography.Decryptor = DecryptorAesCbc(key, init_vec)


def encrypt_asymmetric(pubkey, data, policy_uri):
    """
    Encrypt data with pubkey using an asymmetric algorithm.
    The algorithm is selected by policy_uri.
    Returns a tuple (encrypted_data, algorithm_uri)
    """
    for cls in [SecurityPolicyBasic256, SecurityPolicyBasic128Rsa15]:
        if policy_uri == cls.URI:
            return (cls.encrypt_asymmetric(pubkey, data),
                    cls.AsymmetricEncryptionURI)
    raise UaError("Unsupported security policy `{}`".format(uri))


1	1	from abc import ABCMeta, abstractmethod
2	1	from opcua.ua import CryptographyNone, SecurityPolicy
3	1	from opcua.ua import MessageSecurityMode
4	1	from opcua.ua import UaError
5	1	try:
6	1	from opcua.crypto import uacrypto
7		CRYPTOGRAPHY_AVAILABLE = True
8	1	except ImportError:
9	1	CRYPTOGRAPHY_AVAILABLE = False
10
11
12	1	def require_cryptography(obj):
13		"""
14		Raise exception if cryptography module is not available.
15		Call this function in constructors.
16		"""
17		if not CRYPTOGRAPHY_AVAILABLE:
18		raise UaError("Can't use {}, cryptography module is not installed".format(obj.__class__.__name__))
19
20
21	1	class Signer(object):
22		"""
23		Abstract base class for cryptographic signature algorithm
24		"""
25
26	1	__metaclass__ = ABCMeta
27
28	1	@abstractmethod
29		def signature_size(self):
30		pass
31
32	1	@abstractmethod
33		def signature(self, data):
34		pass
35
36
37	1	class Verifier(object):
38		"""
39		Abstract base class for cryptographic signature verification
40		"""
41
42	1	__metaclass__ = ABCMeta
43
44	1	@abstractmethod
45		def signature_size(self):
46		pass
47
48	1	@abstractmethod
49		def verify(self, data, signature):
50		pass
51
52
53	1	class Encryptor(object):
54		"""
55		Abstract base class for encryption algorithm
56		"""
57
58	1	__metaclass__ = ABCMeta
59
60	1	@abstractmethod
61		def plain_block_size(self):
62		pass
63
64	1	@abstractmethod
65		def encrypted_block_size(self):
66		pass
67
68	1	@abstractmethod
69		def encrypt(self, data):
70		pass
71
72
73	1	class Decryptor(object):
74		"""
75		Abstract base class for decryption algorithm
76		"""
77
78	1	__metaclass__ = ABCMeta
79
80	1	@abstractmethod
81		def plain_block_size(self):
82		pass
83
84	1	@abstractmethod
85		def encrypted_block_size(self):
86		pass
87
88	1	@abstractmethod
89		def decrypt(self, data):
90		pass
91
92
93	1	class Cryptography(CryptographyNone):
94		"""
95		Security policy: Sign or SignAndEncrypt
96		"""
97
98	1	def __init__(self, mode=MessageSecurityMode.Sign):
99		self.Signer = None
100		self.Verifier = None
101		self.Encryptor = None
102		self.Decryptor = None
103		assert mode in (MessageSecurityMode.Sign,
104		MessageSecurityMode.SignAndEncrypt)
105		self.is_encrypted = (mode == MessageSecurityMode.SignAndEncrypt)
106
107	1	def plain_block_size(self):
108		"""
109		Size of plain text block for block cipher.
110		"""
111		if self.is_encrypted:
112		return self.Encryptor.plain_block_size()
113		return 1
114
115	1	def encrypted_block_size(self):
116		"""
117		Size of encrypted text block for block cipher.
118		"""
119		if self.is_encrypted:
120		return self.Encryptor.encrypted_block_size()
121		return 1
122
123	1	def padding(self, size):
124		"""
125		Create padding for a block of given size.
126		plain_size = size + len(padding) + signature_size()
127		plain_size = N * plain_block_size()
128		"""
129		if not self.is_encrypted:
130		return b''
131		block_size = self.Encryptor.plain_block_size()
132		rem = (size + self.signature_size() + 1) % block_size
133		if rem != 0:
134		rem = block_size - rem
135		return bytes(bytearray([rem])) * (rem + 1)
136
137	1	def min_padding_size(self):
138		if self.is_encrypted:
139		return 1
140		return 0
141
142	1	def signature_size(self):
143		return self.Signer.signature_size()
144
145	1	def signature(self, data):
146		return self.Signer.signature(data)
147
148	1	def vsignature_size(self):
149		return self.Verifier.signature_size()
150
151	1	def verify(self, data, sig):
152		self.Verifier.verify(data, sig)
153
154	1	def encrypt(self, data):
155		if self.is_encrypted:
156		assert len(data) % self.Encryptor.plain_block_size() == 0
157		return self.Encryptor.encrypt(data)
158		return data
159
160	1	def decrypt(self, data):
161		if self.is_encrypted:
162		return self.Decryptor.decrypt(data)
163		return data
164
165	1	def remove_padding(self, data):
166		if self.is_encrypted:
167		pad_size = bytearray(data[-1:])[0] + 1
168		return data[:-pad_size]
169		return data
170
171
172	1	class SignerRsa(Signer):
173
174	1	def __init__(self, client_pk):
175		require_cryptography(self)
176		self.client_pk = client_pk
177		self.key_size = self.client_pk.key_size // 8
178
179	1	def signature_size(self):
180		return self.key_size
181
182	1	def signature(self, data):
183		return uacrypto.sign_sha1(self.client_pk, data)
184
185
186	1	class VerifierRsa(Verifier):
187
188	1	def __init__(self, server_cert):
189		require_cryptography(self)
190		self.server_cert = server_cert
191		self.key_size = self.server_cert.public_key().key_size // 8
192
193	1	def signature_size(self):
194		return self.key_size
195
196	1	def verify(self, data, signature):
197		uacrypto.verify_sha1(self.server_cert, data, signature)
198
199
200	1	class EncryptorRsa(Encryptor):
201
202	1	def __init__(self, server_cert, enc_fn, padding_size):
203		require_cryptography(self)
204		self.server_cert = server_cert
205		self.key_size = self.server_cert.public_key().key_size // 8
206		self.encryptor = enc_fn
207		self.padding_size = padding_size
208
209	1	def plain_block_size(self):
210		return self.key_size - self.padding_size
211
212	1	def encrypted_block_size(self):
213		return self.key_size
214
215	1	def encrypt(self, data):
216		encrypted = b''
217		block_size = self.plain_block_size()
218		for i in range(0, len(data), block_size):
219		encrypted += self.encryptor(self.server_cert.public_key(),
220		data[i: i + block_size])
221		return encrypted
222
223
224	1	class DecryptorRsa(Decryptor):
225
226	1	def __init__(self, client_pk, dec_fn, padding_size):
227		require_cryptography(self)
228		self.client_pk = client_pk
229		self.key_size = self.client_pk.key_size // 8
230		self.decryptor = dec_fn
231		self.padding_size = padding_size
232
233	1	def plain_block_size(self):
234		return self.key_size - self.padding_size
235
236	1	def encrypted_block_size(self):
237		return self.key_size
238
239	1	def decrypt(self, data):
240		decrypted = b''
241		block_size = self.encrypted_block_size()
242		for i in range(0, len(data), block_size):
243		decrypted += self.decryptor(self.client_pk,
244		data[i: i + block_size])
245		return decrypted
246
247
248	1	class SignerAesCbc(Signer):
249
250	1	def __init__(self, key):
251		require_cryptography(self)
252		self.key = key
253
254	1	def signature_size(self):
255		return uacrypto.sha1_size()
256
257	1	def signature(self, data):
258		return uacrypto.hmac_sha1(self.key, data)
259
260
261	1	class VerifierAesCbc(Verifier):
262
263	1	def __init__(self, key):
264		require_cryptography(self)
265		self.key = key
266
267	1	def signature_size(self):
268		return uacrypto.sha1_size()
269
270	1	def verify(self, data, signature):
271		expected = uacrypto.hmac_sha1(self.key, data)
272		if signature != expected:
273		raise uacrypto.InvalidSignature
274
275
276	1	class EncryptorAesCbc(Encryptor):
277
278	1	def __init__(self, key, init_vec):
279		require_cryptography(self)
280		self.cipher = uacrypto.cipher_aes_cbc(key, init_vec)
281
282	1	def plain_block_size(self):
283		return self.cipher.algorithm.key_size // 8
284
285	1	def encrypted_block_size(self):
286		return self.cipher.algorithm.key_size // 8
287
288	1	def encrypt(self, data):
289		return uacrypto.cipher_encrypt(self.cipher, data)
290
291
292	1	class DecryptorAesCbc(Decryptor):
293
294	1	def __init__(self, key, init_vec):
295		require_cryptography(self)
296		self.cipher = uacrypto.cipher_aes_cbc(key, init_vec)
297
298	1	def plain_block_size(self):
299		return self.cipher.algorithm.key_size // 8
300
301	1	def encrypted_block_size(self):
302		return self.cipher.algorithm.key_size // 8
303
304	1	def decrypt(self, data):
305		return uacrypto.cipher_decrypt(self.cipher, data)
306
307
308	1	class SecurityPolicyBasic128Rsa15(SecurityPolicy):
309		"""
310		Security Basic 128Rsa15
311		A suite of algorithms that uses RSA15 as Key-Wrap-algorithm
312		and 128-Bit (16 bytes) for encryption algorithms.
313		- SymmetricSignatureAlgorithm - HmacSha1
314		(http://www.w3.org/2000/09/xmldsig#hmac-sha1)
315		- SymmetricEncryptionAlgorithm - Aes128
316		(http://www.w3.org/2001/04/xmlenc#aes128-cbc)
317		- AsymmetricSignatureAlgorithm - RsaSha1
318		(http://www.w3.org/2000/09/xmldsig#rsa-sha1)
319		- AsymmetricKeyWrapAlgorithm - KwRsa15
320		(http://www.w3.org/2001/04/xmlenc#rsa-1_5)
321		- AsymmetricEncryptionAlgorithm - Rsa15
322		(http://www.w3.org/2001/04/xmlenc#rsa-1_5)
323		- KeyDerivationAlgorithm - PSha1
324		(http://docs.oasis-open.org/ws-sx/ws-secureconversation/200512/dk/p_sha1)
325		- DerivedSignatureKeyLength - 128 (16 bytes)
326		- MinAsymmetricKeyLength - 1024 (128 bytes)
327		- MaxAsymmetricKeyLength - 2048 (256 bytes)
328		- CertificateSignatureAlgorithm - Sha1
329
330		If a certificate or any certificate in the chain is not signed with
331		a hash that is Sha1 or stronger then the certificate shall be rejected.
332		"""
333
334	1	URI = "http://opcfoundation.org/UA/SecurityPolicy#Basic128Rsa15"
335	1	signature_key_size = 16
336	1	symmetric_key_size = 16
337	1	AsymmetricEncryptionURI = "http://www.w3.org/2001/04/xmlenc#rsa-1_5"
338
339	1	@staticmethod
340		def encrypt_asymmetric(pubkey, data):
341		return uacrypto.encrypt_rsa15(pubkey, data)
342
343	1	def __init__(self, server_cert, client_cert, client_pk, mode):
344		require_cryptography(self)
345		if isinstance(server_cert, bytes):
346		server_cert = uacrypto.x509_from_der(server_cert)
347		# even in Sign mode we need to asymmetrically encrypt secrets
348		# transmitted in OpenSecureChannel. So SignAndEncrypt here
349		self.asymmetric_cryptography = Cryptography(
350		MessageSecurityMode.SignAndEncrypt)
351		self.asymmetric_cryptography.Signer = SignerRsa(client_pk)
352		self.asymmetric_cryptography.Verifier = VerifierRsa(server_cert)
353		self.asymmetric_cryptography.Encryptor = EncryptorRsa(
354		server_cert, uacrypto.encrypt_rsa15, 11)
355		self.asymmetric_cryptography.Decryptor = DecryptorRsa(
356		client_pk, uacrypto.decrypt_rsa15, 11)
357		self.symmetric_cryptography = Cryptography(mode)
358		self.Mode = mode
359		self.server_certificate = uacrypto.der_from_x509(server_cert)
360		self.client_certificate = uacrypto.der_from_x509(client_cert)
361
362	1	def make_symmetric_key(self, nonce1, nonce2):
363		key_sizes = (self.signature_key_size, self.symmetric_key_size, 16)
364
365		(sigkey, key, init_vec) = uacrypto.p_sha1(nonce2, nonce1, key_sizes)
366		self.symmetric_cryptography.Signer = SignerAesCbc(sigkey)
367		self.symmetric_cryptography.Encryptor = EncryptorAesCbc(key, init_vec)
368
369		(sigkey, key, init_vec) = uacrypto.p_sha1(nonce1, nonce2, key_sizes)
370		self.symmetric_cryptography.Verifier = VerifierAesCbc(sigkey)
371		self.symmetric_cryptography.Decryptor = DecryptorAesCbc(key, init_vec)
372
373
374	1	class SecurityPolicyBasic256(SecurityPolicy):
375		"""
376		Security Basic 256
377		A suite of algorithms that are for 256-Bit (32 bytes) encryption,
378		algorithms include:
379		- SymmetricSignatureAlgorithm - HmacSha1
380		(http://www.w3.org/2000/09/xmldsig#hmac-sha1)
381		- SymmetricEncryptionAlgorithm - Aes256
382		(http://www.w3.org/2001/04/xmlenc#aes256-cbc)
383		- AsymmetricSignatureAlgorithm - RsaSha1
384		(http://www.w3.org/2000/09/xmldsig#rsa-sha1)
385		- AsymmetricKeyWrapAlgorithm - KwRsaOaep
386		(http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p)
387		- AsymmetricEncryptionAlgorithm - RsaOaep
388		(http://www.w3.org/2001/04/xmlenc#rsa-oaep)
389		- KeyDerivationAlgorithm - PSha1
390		(http://docs.oasis-open.org/ws-sx/ws-secureconversation/200512/dk/p_sha1)
391		- DerivedSignatureKeyLength - 192 (24 bytes)
392		- MinAsymmetricKeyLength - 1024 (128 bytes)
393		- MaxAsymmetricKeyLength - 2048 (256 bytes)
394		- CertificateSignatureAlgorithm - Sha1
395
396		If a certificate or any certificate in the chain is not signed with
397		a hash that is Sha1 or stronger then the certificate shall be rejected.
398		"""
399
400	1	URI = "http://opcfoundation.org/UA/SecurityPolicy#Basic256"
401	1	signature_key_size = 24
402	1	symmetric_key_size = 32
403	1	AsymmetricEncryptionURI = "http://www.w3.org/2001/04/xmlenc#rsa-oaep"
404
405	1	@staticmethod
406		def encrypt_asymmetric(pubkey, data):
407		return uacrypto.encrypt_rsa_oaep(pubkey, data)
408
409	1	def __init__(self, server_cert, client_cert, client_pk, mode):
410		require_cryptography(self)
411		if isinstance(server_cert, bytes):
412		server_cert = uacrypto.x509_from_der(server_cert)
413		# even in Sign mode we need to asymmetrically encrypt secrets
414		# transmitted in OpenSecureChannel. So SignAndEncrypt here
415		self.asymmetric_cryptography = Cryptography(
416		MessageSecurityMode.SignAndEncrypt)
417		self.asymmetric_cryptography.Signer = SignerRsa(client_pk)
418		self.asymmetric_cryptography.Verifier = VerifierRsa(server_cert)
419		self.asymmetric_cryptography.Encryptor = EncryptorRsa(
420		server_cert, uacrypto.encrypt_rsa_oaep, 42)
421		self.asymmetric_cryptography.Decryptor = DecryptorRsa(
422		client_pk, uacrypto.decrypt_rsa_oaep, 42)
423		self.symmetric_cryptography = Cryptography(mode)
424		self.Mode = mode
425		self.server_certificate = uacrypto.der_from_x509(server_cert)
426		self.client_certificate = uacrypto.der_from_x509(client_cert)
427
428	1	def make_symmetric_key(self, nonce1, nonce2):
429		# specs part 6, 6.7.5
430		key_sizes = (self.signature_key_size, self.symmetric_key_size, 16)
431
432		(sigkey, key, init_vec) = uacrypto.p_sha1(nonce2, nonce1, key_sizes)
433		self.symmetric_cryptography.Signer = SignerAesCbc(sigkey)
434		self.symmetric_cryptography.Encryptor = EncryptorAesCbc(key, init_vec)
435
436		(sigkey, key, init_vec) = uacrypto.p_sha1(nonce1, nonce2, key_sizes)
437		self.symmetric_cryptography.Verifier = VerifierAesCbc(sigkey)
438		self.symmetric_cryptography.Decryptor = DecryptorAesCbc(key, init_vec)
439
440
441	1	def encrypt_asymmetric(pubkey, data, policy_uri):
442		"""
443		Encrypt data with pubkey using an asymmetric algorithm.
444		The algorithm is selected by policy_uri.
445		Returns a tuple (encrypted_data, algorithm_uri)
446		"""
447		for cls in [SecurityPolicyBasic256, SecurityPolicyBasic128Rsa15]:
448		if policy_uri == cls.URI:
449		return (cls.encrypt_asymmetric(pubkey, data),
450		cls.AsymmetricEncryptionURI)
451		raise UaError("Unsupported security policy `{}`".format(uri))
452

FreeOpcUa / python-opcua

Pull Request — master (#128)

encrypt_asymmetric() A

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