Don't ever encrypt the same message twice that way, or you're likely to
fall to a common modulus attack, I believe.
Looks like it (common modulus attack involves same n, different (e,d) pairs).
However, you're likely to be picking a random symmetric key as the
message, and Schneier even
Don't ever encrypt the same message twice that way, or you're likely to
fall to a common modulus attack, I believe.
Looks like it (common modulus attack involves same n,
different (e,d) pairs).
However, you're likely to be picking a random symmetric key as the
message, and Schneier
By my calculations, it looks like you could take a keypair n,e,d and
some integer x and let e'=e^x and d'=d^x, and RSA would still work,
albeit slowly. Reminds me of blinding, to some extent, except we're
working with key material and not plaintext/ciphertext.
Since I'm on the topic, does doing
On 11/4/05, Travis H. [EMAIL PROTECTED] wrote:
By my calculations, it looks like you could take a keypair n,e,d and
some integer x and let e'=e^x and d'=d^x, and RSA would still work,
albeit slowly. Reminds me of blinding, to some extent, except we're
working with key material and not
On 10/25/05, Travis H. [EMAIL PROTECTED] wrote:
More on topic, I recently heard about a scam involving differential
reversibility between two remote payment systems. The fraudster sends
you an email asking you to make a Western Union payment to a third
party, and deposits the requested amount
One other point with regard to Daniel Nagy's paper at
http://www.epointsystem.org/~nagydani/ICETE2005.pdf
A good way to organize papers like this is to first present the
desired properties of systems like yours (and optionally show that
other systems fail to meet one or more of these properties);
From: cyphrpunk [EMAIL PROTECTED]
Sent: Oct 27, 2005 9:15 PM
To: James A. Donald [EMAIL PROTECTED]
Cc: cryptography@metzdowd.com, [EMAIL PROTECTED]
Subject: Re: On Digital Cash-like Payment Systems
On 10/26/05, James A. Donald [EMAIL PROTECTED] wrote:
How does one inflate a key?
Just make
On 10/28/05, Daniel A. Nagy [EMAIL PROTECTED] wrote:
Irreversibility of transactions hinges on two features of the proposed
systetm: the fundamentally irreversible nature of publishing information in
the public records and the fact that in order to invalidate a secret, one
needs to know it;
If you have
to be that confident in your computer security to use the payment
system, it's not going to have many clients.
Maybe the trusted computing platform (palladium) may have something to
offer after all, namely enabling naive users to use services that
require confidence in their own
PROTECTED] (Daniel A. Nagy)
Subject:Re: [fc-discuss] Financial Cryptography Update: On
Digital Cash-like Payment Systems
One intresting security measure protecting valuable digital assets (WM
protects private keys this way) is inflating them before encryption.
While it does
On 10/22/05, Ian G [EMAIL PROTECTED] wrote:
R. Hirschfeld wrote:
This is not strictly correct. The payer can reveal the blinding
factor, making the payment traceable. I believe Chaum deliberately
chose for one-way untraceability (untraceable by the payee but not by
the payer) in order
On 10/24/05, Steve Schear [EMAIL PROTECTED] wrote:
I don't think E-gold ever held out its system as non-reversible with proper
court order. All reverses I am aware happened either due to some technical
problem with their system or an order from a court of competence in the
matter at hand.
On 10/24/05, John Kelsey [EMAIL PROTECTED] wrote:
More to the point, an irreversible payment system raises big practical
problems in a world full of very hard-to-secure PCs running the
relevant software. One exploitable software bug, properly used, can
steal an enormous amount of money in an
From: cyphrpunk [EMAIL PROTECTED]
Sent: Oct 24, 2005 5:58 PM
To: John Kelsey [EMAIL PROTECTED]
Subject: Re: [fc-discuss] Financial Cryptography Update: On Digital Cash-like
Payment Systems
...
Digital wallets will require real security in user PCs. Still I don't
see why we don't already have
R. Hirschfeld wrote:
Date: Thu, 20 Oct 2005 11:31:39 -0700
From: cyphrpunk [EMAIL PROTECTED]
2. Cash payments are final. After the fact, the paying party has no
means to reverse the payment. We call this property of cash
transactions _irreversibility_.
Certainly Chaum ecash has this
As far as the issue of receipts in Chaumian ecash, there have been a
couple of approaches discussed.
The simplest goes like this. If Alice will pay Bob, Bob supplies Alice
with a blinded proto-coin, along with a signed statement, I will
perform service X if Alice supplies me with a mint signature
On Thu, 20 Oct 2005, cyphrpunk wrote:
system without excessive complications. Only the fifth point, the
ability for outsiders to monitor the amount of cash in circulation, is
not satisfied. But even then, the ecash mint software, and procedures
and controls followed by the issuer, could be
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