Re: [fc-discuss] Financial Cryptography Update: On Digital Cash-like Payment Systems
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 security. One could argue it's like going to a Vegas casino; software vendors (MS *cough* MS) probably won't cheat you in such a system because they don't have to; the odds are in their favor already. The whole system is designed to assure they get paid, and they have a lot to lose (confidence in the platform) by cheating you (at least in ways that can be detected). And since you won't be able to do anything to compromise the security, you can't screw it up. While I wouldn't see an advantage in that, I might recommend it for my grandmother. 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 plus a bonus for you using paypal. The victim makes the irreversible payment using Western Union, and later finds out the credit card used to make the paypal payment was stolen when paypal reverses the transaction, leaving the victim short. -- http://www.lightconsulting.com/~travis/ -- We already have enough fast, insecure systems. -- Schneier Ferguson GPG fingerprint: 50A1 15C5 A9DE 23B9 ED98 C93E 38E9 204A 94C2 641B - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
Re: On the orthogonality of anonymity to current market demand
From: R.A. Hettinga [EMAIL PROTECTED] Sent: Oct 25, 2005 8:34 AM To: cryptography@metzdowd.com, [EMAIL PROTECTED] Subject: On the orthogonality of anonymity to current market demand ... That is to say, your analysis conflicts with the whole trend towards T-0 trading, execution, clearing and settlement in the capital markets, and, frankly, with all payment in general as it gets increasingly granular and automated in nature. The faster you can trade or transact business with the surety that the asset in question is now irrevocably yours, the more trades and transactions you can do, which benefits not only the individual trader but markets as a whole. The prerequisite for all this is that when the asset changes hands, it's very nearly certain that this was the intention of the asset's previous owner. My point isn't to express my love for book-entry payment systems. There's plenty to hate about them. But if the alternative is an anonymous, irreversible payment system whose control lies in software running alongside three pieces of spyware on my Windows box, they probably still win for most people. Even bad payment systems are better than ones that let you have everything in your wallet stolen by a single attack. ... However anonymous irrevocability might offend one's senses and cause one to imagine the imminent heat-death of the financial universe (see Gibbon, below... :-)), I think that technology will instead step up to the challenge and become more secure as a result. What's with the heat-death nonsense? Physical bearer instruments imply stout locks and vaults and alarm systems and armed guards and all the rest, all the way down to infrastructure like police forces and armies (private or public) to avoid having the biggest gang end up owning all the gold. Electronic bearer instruments imply the same kinds of things, and the infrastructure for that isn't in place. It's like telling people to store their net worth in their homes, in gold. That can work, but you probably can't leave the cheapest lock sold at Home Depot on your front door and stick the gold coins in the same drawer where you used to keep your checkbook. And, since internet bearer transactions are, by their very design, more secure on public networks than book-entry transactions are in encrypted tunnels on private networks, they could even be said to be secure *in spite* of the fact that they're anonymous; that -- as it ever was in cryptography -- business can be transacted between two parties even though they don't know, or trust, each other. Why do you say internet bearer transactions are more secure? I can see more efficient, but why more secure? It looks to me like both kinds of payment system are susceptible to the same broad classes of attacks (bank misbehavior (for a short time), someone finding a software bug, someone breaking a crypto algorithm or protocol). What makes one more secure than the other? ... Cheers, RAH --John Kelsey - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
Re: [PracticalSecurity] Anonymity - great technology but hardly used
--- Travis H. [EMAIL PROTECTED] wrote: [snip] Another issue involves the ease of use when switching between a [slower] anonymous service and a fast non-anonymous service. I have a tool called metaprox on my website (see URL in sig) that allows you to choose what proxies you use on a domain-by-domain basis. Something like this is essential if you want to be consistent about accessing certain sites only through an anonymous proxy. Short of that, perhaps a Firefox plug-in that allows you to select proxies with a single click would be useful. You can already do the latter with SwitchProxy (http://www.roundtwo.com/product/switchproxy). Basically, it's a Firefox extension that saves you the trouble of going into the 'preferences' dialogue everytime you want to switch from one proxy to another (or go from using a proxy to not using one, that is). It works like a charm with tor and a local proxy. It also has a Anonymizer mode, which cycles through a list of proxies in an attempt to give you some kind of pseudo-anonymity (which I guess is good enough for many people). Jörn __ Yahoo! Mail - PC Magazine Editors' Choice 2005 http://mail.yahoo.com - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
Re: [EMAIL PROTECTED]: Skype security evaluation]
On Mon, 24 Oct 2005, cyphrpunk wrote: Is it possible that Skype doesn't use RSA encryption? Or if they do, do they do it without using any padding, and is that safe? You may want to read the report itself: http://www.skype.com/security/files/2005-031%20security%20evaluation.pdf and perhaps section 3.2.3 (about padding) and 3.2.2 (about how RSA is used) may help with this (and what it is used for in section 2). Dw. - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
Re: [EMAIL PROTECTED]: Skype security evaluation]
On Wed, Oct 26, 2005 at 07:47:22AM -0700, Dirk-Willem van Gulik wrote: On Mon, 24 Oct 2005, cyphrpunk wrote: Is it possible that Skype doesn't use RSA encryption? Or if they do, do they do it without using any padding, and is that safe? You may want to read the report itself: http://www.skype.com/security/files/2005-031%20security%20evaluation.pdf and perhaps section 3.2.3 (about padding) and 3.2.2 (about how RSA is used) may help with this (and what it is used for in section 2). I just reread those sections and I still don't see anything about RSA encryption padding either. 3.2.2 just has some useless factoids about the RSA implementation (but neglects to mention important implementation points, like if blinding is used, or if signatures are verified before being released). 3.2.3 describes the signature padding, but makes no mention of the encryption padding, or even that a padding method is used for encryption. Jack - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
High-risk flaws in Skype
http://searchsecurity.techtarget.com/originalContent/ 0,289142,sid14_gci1136763,00.html?track=NL-102ad=530772 - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
On Digital Cash-like Payment Systems
Date sent: Tue, 25 Oct 2005 00:38:36 +0200 To: cyphrpunk [EMAIL PROTECTED] Copies to: John Kelsey [EMAIL PROTECTED], Ian G [EMAIL PROTECTED], [EMAIL PROTECTED], cryptography@metzdowd.com, [EMAIL PROTECTED] From: [EMAIL 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 not protect agains trojan applications, it does a surprisingly good job at reducing attacks following the key logging + file theft pattern. This security measure depends on two facts: storage being much cheaper than bandwidth and transmission of long files being detectable, allowing for detecting and thwarting an attack in progress. How does one inflate a key? -- Daniel - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
