在 pycrypto 中为 RSA 使用致盲因子

Question

在 python 中，我正在尝试隐藏和取消隐藏一条消息。当我取消隐藏消息时，我没有收到原始消息。有谁知道我可能做错了什么。以下是我的代码：

s = 'Hello'
loadedPublic = get_publickey()
loadedPrivate = get_privatekey()

pub = loadedPublic.blind(s,23L)
pub2 = loadedPublic.unblind(pub,23L)
return HttpResponse(pub2)

Answer 1

盲化是一种使用随机元素的加密。它通常用于 Blind Signatures，看起来像这样：

from Crypto.PublicKey import RSA
from Crypto.Hash import SHA256
from random import SystemRandom

# Signing authority (SA) key
priv = RSA.generate(3072)
pub = priv.publickey()

## Protocol: Blind signature ##

# must be guaranteed to be chosen uniformly at random
r = SystemRandom().randrange(pub.n >> 10, pub.n)
msg = "my message" * 50 # large message (larger than the modulus)

# hash message so that messages of arbitrary length can be signed
hash = SHA256.new()
hash.update(msg)
msgDigest = hash.digest()

# user computes
msg_blinded = pub.blind(msgDigest, r)

# SA computes
msg_blinded_signature = priv.sign(msg_blinded, 0)

# user computes
msg_signature = pub.unblind(msg_blinded_signature[0], r)

# Someone verifies
hash = SHA256.new()
hash.update(msg)
msgDigest = hash.digest()
print("Message is authentic: " + str(pub.verify(msgDigest, (msg_signature,))))

This是这样实现的，所以不能直接对消息进行解盲，因为你没有d，所以必须先对被屏蔽的元素进行签名。为了使盲签名安全，需要在签名模数范围内随机生成盲因子r。

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