[Cryptography] Zoom publishes draft cryptographic design for end-to-end encryption
crypto at senderek.ie
Mon Jun 8 15:58:33 EDT 2020
On Mon, 8 Jun 2020, Stephan Neuhaus wrote:
> On 6/5/20 10:33 AM, Ralf Senderek wrote:
>> Well, everything can be overdone, because forcing a 2048 bit n to be used
>> with a 2041 bit e will give them quite a handy, small private decryption
>> exponent d.
> Will it? Can I ask you to explain your reasoning?
If I'm not mistaken then phi(n) = (p-1)*(q-1) is of roughly the same size
And if e*d = 1 mod phi(n) , then you *might* find a small d if e is large.
You may as well find a large d if e is large, but any small one that fits
the bill will decrypt your ossifrage.
PS: doesn't convince you?
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