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Added loading of DER and PEM encoded private keys
1 parent 834ae62 commit fa34679

3 files changed

Lines changed: 188 additions & 14 deletions

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‎rsa/key.py‎

Lines changed: 81 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -6,6 +6,7 @@
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'''
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import rsa.prime
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import rsa.pem
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class PublicKey(object):
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'''Represents a public RSA key.
@@ -75,19 +76,6 @@ class PrivateKey(object):
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'''
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# RSAPrivateKey ::= SEQUENCE {
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# version Version,
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# modulus INTEGER, -- n
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# publicExponent INTEGER, -- e
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# privateExponent INTEGER, -- d
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# prime1 INTEGER, -- p
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# prime2 INTEGER, -- q
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# exponent1 INTEGER, -- d mod (p-1)
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# exponent2 INTEGER, -- d mod (q-1)
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# coefficient INTEGER, -- (inverse of q) mod p
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# otherPrimeInfos OtherPrimeInfos OPTIONAL
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# }
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__slots__ = ('n', 'e', 'd', 'p', 'q', 'exp1', 'exp2', 'coef')
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def __init__(self, n, e, d, p, q, exp1=None, exp2=None, coef=None):
@@ -119,6 +107,24 @@ def __getitem__(self, key):
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def __repr__(self):
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return u'PrivateKey(%(n)i, %(e)i, %(d)i, %(p)i, %(q)i)' % self
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def __eq__(self, other):
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if other is None:
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return False
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if not isinstance(other, PrivateKey):
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return False
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return (self.n == other.n and
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self.e == other.e and
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self.d == other.d and
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self.p == other.p and
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self.q == other.q and
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self.exp1 == other.exp1 and
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self.exp2 == other.exp2 and
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self.coef == other.coef)
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def __ne__(self, other):
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return not (self == other)
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def extended_gcd(a, b):
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"""Returns a tuple (r, i, j) such that r = gcd(a, b) = ia + jb
@@ -234,7 +240,68 @@ def newkeys(nbits):
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PrivateKey(n, e, d, p, q)
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)
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__all__ = ['PublicKey', 'PrivateKey', 'newkeys']
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def load_private_key_der(keyfile):
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r'''Loads a key in DER format.
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@param keyfile: contents of a DER-encoded file that contains the private
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key.
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@return: a PrivateKey object
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First let's construct a DER encoded key:
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>>> import base64
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>>> b64der = 'MC4CAQACBQDeKYlRAgMBAAECBQDHn4npAgMA/icCAwDfxwIDANcXAgInbwIDAMZt'
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>>> der = base64.decodestring(b64der)
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This loads the file:
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>>> load_private_key_der(der)
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PrivateKey(3727264081, 65537, 3349121513, 65063, 57287)
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'''
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from pyasn1.codec.der import decoder
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(priv, _) = decoder.decode(keyfile)
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# ASN.1 contents of DER encoded private key:
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#
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# RSAPrivateKey ::= SEQUENCE {
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# version Version,
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# modulus INTEGER, -- n
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# publicExponent INTEGER, -- e
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# privateExponent INTEGER, -- d
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# prime1 INTEGER, -- p
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# prime2 INTEGER, -- q
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# exponent1 INTEGER, -- d mod (p-1)
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# exponent2 INTEGER, -- d mod (q-1)
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# coefficient INTEGER, -- (inverse of q) mod p
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# otherPrimeInfos OtherPrimeInfos OPTIONAL
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# }
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if priv[0] != 0:
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raise ValueError('Unable to read this file, version %s != 0' % priv[0])
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return PrivateKey(*priv[1:9])
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def load_private_key_pem(keyfile):
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'''Loads a PEM-encoded private key file.
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The contents of the file before the "-----BEGIN RSA PRIVATE KEY-----" and
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after the "-----END RSA PRIVATE KEY-----" lines is ignored.
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@param keyfile: contents of a PEM-encoded file that contains the private
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key.
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@return: a PrivateKey object
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'''
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PEM_START = '-----BEGIN RSA PRIVATE KEY-----'
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PEM_END = '-----END RSA PRIVATE KEY-----'
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der = rsa.pem.load_pem(keyfile, PEM_START, PEM_END)
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return load_private_key_der(der)
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__all__ = ['PublicKey', 'PrivateKey', 'newkeys', 'load']
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if __name__ == '__main__':
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import doctest

‎rsa/pem.py‎

Lines changed: 60 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,60 @@
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'''Functions that load and write PEM-encoded files.'''
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import base64
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def load_pem(contents, pem_start, pem_end):
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'''Loads a PEM file.
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Only considers the information between lines "pem_start" and "pem_end". For
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private keys these are '-----BEGIN RSA PRIVATE KEY-----' and
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'-----END RSA PRIVATE KEY-----'
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@param contents: the contents of the file to interpret
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@param pem_start: the start marker of the PEM content, such as
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'-----BEGIN RSA PRIVATE KEY-----'
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@param pem_end: the end marker of the PEM content, such as
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'-----END RSA PRIVATE KEY-----'
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@return the base64-decoded content between the start and end markers.
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@raise ValueError: when the content is invalid, for example when the start
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marker cannot be found.
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'''
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pem_lines = []
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in_pem_part = False
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for line in contents.split('\n'):
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line = line.strip()
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# Handle start marker
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if line == pem_start:
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if in_pem_part:
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raise ValueError('Seen start marker "%s" twice' % pem_start)
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in_pem_part = True
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continue
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# Skip stuff before first marker
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if not in_pem_part:
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continue
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# Handle end marker
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if in_pem_part and line == pem_end:
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in_pem_part = False
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break
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pem_lines.append(line)
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# Do some sanity checks
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if not pem_lines:
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raise ValueError('No PEM start marker "%s" found' % pem_start)
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if in_pem_part:
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raise ValueError('No PEM end marker "%s" found' % pem_end)
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# Base64-decode the contents
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pem = ''.join(pem_lines)
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return base64.decodestring(pem)
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‎tests/test_load_save_keys.py‎

Lines changed: 47 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,47 @@
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'''Unittest for saving and loading keys.'''
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import base64
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import unittest
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import rsa.key
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B64PRIV_DER = 'MC4CAQACBQDeKYlRAgMBAAECBQDHn4npAgMA/icCAwDfxwIDANcXAgInbwIDAMZt'
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PRIVATE_DER = base64.decodestring(B64PRIV_DER)
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PRIVATE_PEM = '''
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-----BEGIN CONFUSING STUFF-----
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Cruft before the key
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-----BEGIN RSA PRIVATE KEY-----
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%s
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-----END RSA PRIVATE KEY-----
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Stuff after the key
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-----END CONFUSING STUFF-----
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''' % B64PRIV_DER
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class DerTest(unittest.TestCase):
25+
'''Test saving and loading DER keys.'''
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def test_load_private_key(self):
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'''Test loading private DER keys.'''
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key = rsa.key.load_private_key_der(PRIVATE_DER)
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expected = rsa.key.PrivateKey(3727264081, 65537, 3349121513, 65063, 57287)
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self.assertEqual(expected, key)
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class PemTest(unittest.TestCase):
37+
'''Test saving and loading PEM keys.'''
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def test_load_private_key(self):
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'''Test loading private PEM files.'''
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key = rsa.key.load_private_key_pem(PRIVATE_PEM)
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expected = rsa.key.PrivateKey(3727264081, 65537, 3349121513, 65063, 57287)
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self.assertEqual(expected, key)
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