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Viewing changes to .tox/py35/lib/python3.5/site-packages/wheel/signatures/ed25519py.py

  • Committer: Anita Nayak
  • Date: 2016-10-24 07:10:08 UTC
  • Revision ID: anitanayak@in.ibm.com-20161024071008-tqk3cefak6nc1c69
checking in after fixing lint errors

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.tox/py35/lib/python3.5/site-packages/wheel/signatures/ed25519py.py
 
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# -*- coding: utf-8 -*-
 
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import warnings
 
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import os
 
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from collections import namedtuple
 
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from . import djbec
 
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__all__ = ['crypto_sign', 'crypto_sign_open', 'crypto_sign_keypair', 'Keypair',
 
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           'PUBLICKEYBYTES', 'SECRETKEYBYTES', 'SIGNATUREBYTES']
 
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PUBLICKEYBYTES=32
 
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SECRETKEYBYTES=64
 
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SIGNATUREBYTES=64
 
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Keypair = namedtuple('Keypair', ('vk', 'sk')) # verifying key, secret key
 
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def crypto_sign_keypair(seed=None):
 
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    """Return (verifying, secret) key from a given seed, or os.urandom(32)"""    
 
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    if seed is None:
 
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        seed = os.urandom(PUBLICKEYBYTES)
 
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    else:
 
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        warnings.warn("ed25519ll should choose random seed.",
 
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                      RuntimeWarning)
 
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    if len(seed) != 32:
 
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        raise ValueError("seed must be 32 random bytes or None.")
 
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    skbytes = seed
 
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    vkbytes = djbec.publickey(skbytes)
 
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    return Keypair(vkbytes, skbytes+vkbytes)
 
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def crypto_sign(msg, sk):
 
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    """Return signature+message given message and secret key.
 
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    The signature is the first SIGNATUREBYTES bytes of the return value.
 
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    A copy of msg is in the remainder."""
 
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    if len(sk) != SECRETKEYBYTES:
 
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        raise ValueError("Bad signing key length %d" % len(sk))
 
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    vkbytes = sk[PUBLICKEYBYTES:]
 
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    skbytes = sk[:PUBLICKEYBYTES]
 
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    sig = djbec.signature(msg, skbytes, vkbytes)
 
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    return sig + msg
 
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def crypto_sign_open(signed, vk):
 
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    """Return message given signature+message and the verifying key."""
 
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    if len(vk) != PUBLICKEYBYTES:
 
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        raise ValueError("Bad verifying key length %d" % len(vk))
 
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    rc = djbec.checkvalid(signed[:SIGNATUREBYTES], signed[SIGNATUREBYTES:], vk)
 
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    if not rc:
 
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        raise ValueError("rc != True", rc)    
 
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    return signed[SIGNATUREBYTES:]
 
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