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Add Brainpool EC-curves support
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This commit adds the support of Brainpool curves to jwcrypto. The Brainpool curves defined in RFC 5639 are mandatory for use in german e-health systems as defined by the Federal Office of Information Security (BSI) and National Digital Health Agency (gematik GmbH).

In order to use the public E-Health APIs clients are required to:

* Load and use the Brainpool keys using JWK
* Sign and verify the signatures using the Brainpool elliptic curves using JWS
* Encrypt and decrypt the data using the Brainpool elliptic curves and AES using JWE

At the time of this commit there is no official standardization of these algorithms for JOSE/JWK/JWS/JWE. The use of these algorithms is specified solely by the gematik GmbH – National Digital Health Agency - for use in german e-health applications.

Signed-off-by: Sergej Suskov <git@spilikin.dev>
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spilikin committed Oct 10, 2022
1 parent 14d1f81 commit 55458fa
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Showing 3 changed files with 176 additions and 3 deletions.
53 changes: 52 additions & 1 deletion jwcrypto/jwa.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1053,6 +1053,54 @@ class _A256Gcm(_AesGcm, JWAAlgorithm):
algorithm_use = 'enc'


class _BP256R1(_RawEC, JWAAlgorithm):

name = "BP256R1"
description = (
"ECDSA using Brainpool256R1 curve and SHA-256"
" (unregistered, custom-defined in breach"
" of IETF rules by gematik GmbH)"
)
keysize = 256
algorithm_usage_location = 'alg'
algorithm_use = 'sig'

def __init__(self):
super(_BP256R1, self).__init__('BP-256', hashes.SHA256())


class _BP384R1(_RawEC, JWAAlgorithm):

name = "BP384R1"
description = (
"ECDSA using Brainpool384R1 curve and SHA-384"
" (unregistered, custom-defined in breach"
" of IETF rules by gematik GmbH)"
)
keysize = 384
algorithm_usage_location = 'alg'
algorithm_use = 'sig'

def __init__(self):
super(_BP384R1, self).__init__('BP-384', hashes.SHA384())


class _BP512R1(_RawEC, JWAAlgorithm):

name = "BP512R1"
description = (
"ECDSA using Brainpool512R1 curve and SHA-512"
" (unregistered, custom-defined in breach"
" of IETF rules by gematik GmbH)"
)
keysize = 512
algorithm_usage_location = 'alg'
algorithm_use = 'sig'

def __init__(self):
super(_BP512R1, self).__init__('BP-512', hashes.SHA512())


class JWA:
"""JWA Signing Algorithms.
Expand Down Expand Up @@ -1097,7 +1145,10 @@ class JWA:
'A256CBC-HS512': _A256CbcHs512,
'A128GCM': _A128Gcm,
'A192GCM': _A192Gcm,
'A256GCM': _A256Gcm
'A256GCM': _A256Gcm,
'BP256R1': _BP256R1,
'BP384R1': _BP384R1,
'BP512R1': _BP512R1
}

@classmethod
Expand Down
23 changes: 21 additions & 2 deletions jwcrypto/jwk.py
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Original file line number Diff line number Diff line change
Expand Up @@ -162,7 +162,17 @@ class ParmType(Enum):
'Ed25519': 'Ed25519 signature algorithm key pairs',
'Ed448': 'Ed448 signature algorithm key pairs',
'X25519': 'X25519 function key pairs',
'X448': 'X448 function key pairs'}
'X448': 'X448 function key pairs',
'BP-256': 'BrainpoolP256R1 curve'
' (unregistered, custom-defined in breach'
' of IETF rules by gematik GmbH)',
'BP-384': 'BrainpoolP384R1 curve'
' (unregistered, custom-defined in breach'
' of IETF rules by gematik GmbH)',
'BP-512': 'BrainpoolP512R1 curve'
' (unregistered, custom-defined in breach'
' of IETF rules by gematik GmbH)'
}
"""Registry of allowed Elliptic Curves"""

# RFC 7517 - 8.2
Expand All @@ -186,7 +196,10 @@ class ParmType(Enum):
JWKpycaCurveMap = {'secp256r1': 'P-256',
'secp384r1': 'P-384',
'secp521r1': 'P-521',
'secp256k1': 'secp256k1'}
'secp256k1': 'secp256k1',
'brainpoolP256r1': 'BP-256',
'brainpoolP384r1': 'BP-384',
'brainpoolP512r1': 'BP-512'}

IANANamedInformationHashAlgorithmRegistry = {
'sha-256': hashes.SHA256(),
Expand Down Expand Up @@ -453,6 +466,12 @@ def _get_curve_by_name(self, name, ctype=None):
return ec.SECP521R1()
elif cname == 'secp256k1':
return ec.SECP256K1()
elif cname == 'BP-256':
return ec.BrainpoolP256R1()
elif cname == 'BP-384':
return ec.BrainpoolP384R1()
elif cname == 'BP-512':
return ec.BrainpoolP512R1()
elif cname in _OKP_CURVES_TABLE:
return _OKP_CURVES_TABLE[cname]
else:
Expand Down
103 changes: 103 additions & 0 deletions jwcrypto/tests.py
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Original file line number Diff line number Diff line change
Expand Up @@ -294,7 +294,66 @@
"x": "Ss6na3mcci8Ud4lQrjaB_T40sfKApEcl2RLIWOJdjow",
"y": "7l9qIKtKPW6oEiOYBt7r22Sm0mtFJU-yBkkvMvpscd8",
"d": "GYhU2vrYGZrjLZn71Xniqm54Mi53xiYtaTLawzaf9dA"
}
]
}

PublicKeys_brainpool = {
"keys": [
{
"kty": "EC",
"crv": "BP-256",
"x": "mpkJ29_CYAD0mzQ_MsrbjFMFYtcc9Oxpro37Fa4cLfI",
"y": "iBfhNHk0cI73agNpjbKW62dvuVxn7kxp1Sm8oDnzHl8",
},
{
"kty": "EC",
"crv": "BP-384",
"x": ("WZanneaC2Hi3xslA4znJv7otyEdV5dTPzNUvBjBXPM"
"ytf4mRY9JaAITdItjvUTAh"),
"y": ("KNLRTNdvUg66aB_TVW4POZkE3q8S0YoQrCzYUrExRDe"
"_BXikkqIama-GYQ3UBOQL"),
},
{
"kty": "EC",
"crv": "BP-512",
"x": ("aQXpvz7DH9OK5eFNO9dY3BdPY1v0-8Rg9KC322PY1Jy"
"BJq3EhT0uR_-tgbL2E_aGP6k56lF1xIOOtQxo8zziGA"),
"y": ("l9XLHHncigOPr5Tvnj_mVzBFv6i7rdBQrLTq3RXZlCC"
"_f_q6L2o79K9IrN_J2wWxAfS8ekuGPGlHZUzK-3D9sA"),
}
]
}

PrivateKeys_brainpool = {
"keys": [
{
"kty": "EC",
"crv": "BP-256",
"x": "mpkJ29_CYAD0mzQ_MsrbjFMFYtcc9Oxpro37Fa4cLfI",
"y": "iBfhNHk0cI73agNpjbKW62dvuVxn7kxp1Sm8oDnzHl8",
"d": "KdKRgq0WEM97BQw3jpW_fTOep6fn-Samv4DfDNb-4s4"
},
{
"kty": "EC",
"crv": "BP-384",
"x": ("WZanneaC2Hi3xslA4znJv7otyEdV5dTPzNUvBjBXPM"
"ytf4mRY9JaAITdItjvUTAh"),
"y": ("KNLRTNdvUg66aB_TVW4POZkE3q8S0YoQrCzYUrExRDe"
"_BXikkqIama-GYQ3UBOQL"),
"d": ("B5WeRV0-RztAPAhRbphSAUrsIzy-eSfWGSM5FxOQGlJ"
"cq-ECLA_-SIlH7NdWIEJY")
},
{
"kty": "EC",
"crv": "BP-512",
"x": ("aQXpvz7DH9OK5eFNO9dY3BdPY1v0-8Rg9KC322PY1Jy"
"BJq3EhT0uR_-tgbL2E_aGP6k56lF1xIOOtQxo8zziGA"),
"y": ("l9XLHHncigOPr5Tvnj_mVzBFv6i7rdBQrLTq3RXZlCC"
"_f_q6L2o79K9IrN_J2wWxAfS8ekuGPGlHZUzK-3D9sA"),
"d": ("F_LJ9rebAjOtxoMUfngIywYsnJlZNjy3gxNAEvHjSkL"
"m6RUUdLXDwc50EMp0LeTh1ku039D5kldK3S9Xi0yKZA")
}
]
}

Expand Down Expand Up @@ -385,6 +444,15 @@ def test_generate_EC_key(self):
# New secp256k curve
key = jwk.JWK.generate(kty='EC', curve='secp256k1')
key.get_op_key('verify', 'secp256k1')
# Brainpool256R1 curve
key = jwk.JWK.generate(kty='EC', crv='BP-256')
key.get_op_key('verify', 'BP-256')
# Brainpool384R1 curve
key = jwk.JWK.generate(kty='EC', crv='BP-384')
key.get_op_key('verify', 'BP-384')
# Brainpool256R1 curve
key = jwk.JWK.generate(kty='EC', crv='BP-512')
key.get_op_key('verify', 'BP-512')

def test_generate_OKP_keys(self):
for crv in jwk.ImplementedOkpCurves:
Expand Down Expand Up @@ -576,6 +644,16 @@ def test_create_priKeys_secp256k1(self):
for key in keylist:
jwk.JWK(**key)

def test_create_pubKeys_brainpool(self):
keylist = PublicKeys_brainpool['keys']
for key in keylist:
jwk.JWK(**key)

def test_create_priKeys_brainpool(self):
keylist = PrivateKeys_brainpool['keys']
for key in keylist:
jwk.JWK(**key)

def test_thumbprint_eddsa(self):
for i in range(0, len(PublicKeys_EdDsa['keys'])):
k = jwk.JWK(**PublicKeys_EdDsa['keys'][i])
Expand Down Expand Up @@ -987,6 +1065,31 @@ def test_secp256k1_signing_and_verification(self):
jws_verify.verify(key.public())
self.assertEqual(jws_verify.payload, payload)

def test_brainpool_signing_and_verification(self):
for key_data in PrivateKeys_brainpool['keys']:
key = jwk.JWK(**key_data)
payload = bytes(bytearray(A1_payload))
jws_test = jws.JWS(payload)

curve_name = key.get('crv')
if curve_name == "BP-256":
alg = "BP256R1"
elif curve_name == "BP-384":
alg = "BP384R1"
else:
alg = "BP512R1"

jws_test.allowed_algs = [alg]
jws_test.add_signature(key, None, json_encode({"alg": alg}), None)
jws_test_serialization_compact = jws_test.serialize(compact=True)

jws_verify = jws.JWS()
jws_verify.allowed_algs = [alg]
jws_verify.deserialize(jws_test_serialization_compact)
jws_verify.verify(key.public())

self.assertEqual(jws_verify.payload, payload)

def test_jws_issue_224(self):
key = jwk.JWK().generate(kty='oct')

Expand Down

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