8000 support for PEM format for EC parameters · tlsfuzzer/python-ecdsa@5ddcd9b · GitHub
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support for PEM format for EC parameters
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‎src/ecdsa/curves.py

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Original file line numberDiff line numberDiff line change
@@ -1,5 +1,6 @@
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from __future__ import division
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from six import PY2
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from . import der, ecdsa, ellipticcurve
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from .util import orderlen, number_to_string, string_to_number
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from ._compat import normalise_bytes
@@ -79,6 +80,9 @@ def to_der(self, encoding=None, point_encoding="uncompressed"):
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:param str point_encoding: the point encoding of the generator when
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explicit curve encoding is used. Ignored for ``named_curve``
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format.
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:return: DER encoded ECParameters structure
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:rtype: bytes
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"""
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if encoding is None:
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if self.oid:
@@ -117,6 +121,24 @@ def to_der(self, encoding=None, point_encoding="uncompressed"):
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return der.encode_sequence(*seq_elements)
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def to_pem(self, encoding=None, point_encoding="uncompressed"):
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"""
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Serialise the curve parameters to the :term:`PEM` format.
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:param str encoding: the format to save the curve parameters in.
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Default is ``named_curve``, with fallback being the ``explicit``
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if the OID is not set for the curve.
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:param str point_encoding: the point encoding of the generator when
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explicit curve encoding is used. Ignored for ``named_curve``
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format.
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:return: PEM encoded ECParameters structure
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:rtype: str
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"""
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return der.topem(
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self.to_der(encoding, point_encoding), "EC PARAMETERS"
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)
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@staticmethod
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def from_der(data):
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"""Decode the curve parameters from DER file.
@@ -190,6 +212,21 @@ def from_der(data):
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return i
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return tmp_curve
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@classmethod
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def from_pem(cls, string):
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"""Decode the curve parameters from PEM file.
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:param str string: the text string to decode the parameters from
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"""
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if not PY2 and isinstance(string, str): # pragma: no branch
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string = string.encode()
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ec_param_index = string.find(b"-----BEGIN EC PARAMETERS-----")
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if ec_param_index == -1:
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raise der.UnexpectedDER("EC PARAMETERS PEM header not found")
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return cls.from_der(der.unpem(string[ec_param_index:]))
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193230

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# the SEC curves
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SECP112r1 = Curve(

‎src/ecdsa/test_curves.py

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Original file line numberDiff line numberDiff line change
@@ -24,6 +24,45 @@ def setUpClass(cls):
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"AiEA/////wAAAAD//////////7zm+q2nF56E87nKwvxjJVECAQE="
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)
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def test_from_pem(self):
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pem_params = (
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"-----BEGIN EC PARAMETERS-----\n"
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"MIHgAgEBMCwGByqGSM49AQECIQD/////AAAAAQAAAAAAAAAAAAAAAP/////////\n"
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"//////zBEBCD/////AAAAAQAAAAAAAAAAAAAAAP///////////////AQgWsY12K\n"
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"o6k+ez671VdpiGvGUdBrDMU7D2O848PifSYEsEQQRrF9Hy4SxCR/i85uVjpEDyd\n"
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"wN9gS3rM6D0oTlF2JjClk/jQuL+Gn+bjufrSnwPnhYrzjNXazFezsu2QGg3v1H1\n"
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"AiEA/////wAAAAD//////////7zm+q2nF56E87nKwvxjJVECAQE=\n"
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"-----END EC PARAMETERS-----\n"
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)
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curve = Curve.from_pem(pem_params)
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self.assertIs(curve, NIST256p)
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def test_from_pem_with_wrong_header(self):
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pem_params = (
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"-----BEGIN PARAMETERS-----\n"
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"MIHgAgEBMCwGByqGSM49AQECIQD/////AAAAAQAAAAAAAAAAAAAAAP/////////\n"
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"//////zBEBCD/////AAAAAQAAAAAAAAAAAAAAAP///////////////AQgWsY12K\n"
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"o6k+ez671VdpiGvGUdBrDMU7D2O848PifSYEsEQQRrF9Hy4SxCR/i85uVjpEDyd\n"
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"wN9gS3rM6D0oTlF2JjClk/jQuL+Gn+bjufrSnwPnhYrzjNXazFezsu2QGg3v1H1\n"
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"AiEA/////wAAAAD//////////7zm+q2nF56E87nKwvxjJVECAQE=\n"
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"-----END PARAMETERS-----\n"
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)
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with self.assertRaises(der.UnexpectedDER) as e:
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Curve.from_pem(pem_params)
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self.assertIn("PARAMETERS PEM header", str(e.exception))
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def test_to_pem(self):
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pem_params = (
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b"-----BEGIN EC PARAMETERS-----\n"
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b"BggqhkjOPQMBBw==\n"
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b"-----END EC PARAMETERS-----\n"
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)
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encoding = NIST256p.to_pem()
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self.assertEqual(pem_params, encoding)
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def test_compare_with_different_object(self):
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self.assertNotEqual(NIST256p, 256)
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