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17

Figure out the cost level where you start getting uncomfortable. Calculate the GB that would need to be transferred to reach that cost level. See if you think an attacker will be willing to spend that much effort to hurt you for that amount of money. Every time I run this calculation I end up thinking that if somebody hated me that much, they could ...


14

Amazon does have a Type II SAS 70 report. Requesting a detailed copy of that should show all the controls they have in place. It may that people are asking Amazon the wrong questions. As a quick note, the SAS 70 testing in the future will be referred to as an SOC -- one of those accounting industry quirks. Especially with an Amazon-sized company, one looks ...


13

This is a simple cost / benefit analysis, so it's a business question rather than a security one since you've already decided the merits of how to approach the security aspect. Write your code, benchmark it, and compare numbers in a spreadsheet. For the metal * Cost of metal * Cost per hour in terms of electric bill (assume under full load) * Budget for ...


12

According to the white-paper they use SK-KEM, which is an identity-based encryption scheme. This explains why you do not need the public key of B in order to send an encrypted message to him (the email-address is the public key). Usually identity-based encryption relies on a trusted third party. So their claim that they cannot decrypt the messages ...


11

Anything which is encrypted with PBE (as in "Password Based Encryption") can be the subject of an offline dictionary attack (i.e.: the attacker tries potential passwords). This is a worry unless you have a super-strong password, which is not as easy as it can seem because you also have to remember it, and to type it regularly (if you note it down somewhere, ...


11

The most sensible approach is to assume you cant rely on their privacy - it isn't their responsibility, although there are some services whose selling point is securing this data. If you take that stance, as long as you encrypt all data before it goes to the cloud you can be safe (decide on what level of encryption you need in order to be safe) This ...


10

You'll never be able to know. You can however, exercise reasoning and logical judgement based on The company's ToS. The company's track record. Your trust of the company providing that service. The importance/value of the data handled by that service. Regarding password management; call me a little paranoid, but I really never trust any cloud service ...


9

Encrypting the data with the public key of each agent is a way to implicitly authenticate the agent. You do not really know (in a setup where communications go through a potentially malicious cloud) if the agent really received the data, but you know that only the proper agent could decrypt it; hence, if the data has gone somewhere at all, then it went to ...


9

It is already possible, via end-to-end voting systems like Helios to publicly store voted ballots in the cloud in an encrypted fashion, so that the public can add them up to confirm the totals, and to also check that their own vote was indeed included in the total. Without giving someone a 'receipt' that they can use to sell their vote. Surprising, but ...


9

There was been at least five issues reported over the past few months Problem with authentication, ie if you could access a hard disc that contained a dropbox folder you would have continuous access to their dropbox data Data stored in dropbox is accessible by dropbox employees A recent code update meant that any dropbox account could be accessed with ...


9

I would say no its not suitable for storing criticial information, From the sound of their terms Google essentially owns everyting you upload as well as anything derivitive of your data as well. Here is an excerpt from the verge.com explaining the differences of the 3 major players, notice Google is very liberal with what they can do with your data. ...


8

Homomorphic encryption is about encryption schemes which allow computing with encrypted value without decrypting them. For instance, given E(a) and E(b) (the encryption of a and b), you can compute E(a+b) without knowing a, b nor the decryption key. Homomorphic encryption schemes are very useful in voting schemes, with the following structure: voters ...


8

El Gamal encryption allows for multiplication. This occurs within the group on which El Gamal runs; hence you are multiplying numbers modulo a given prime, not "plain" integers. If you can multiply you can divide (inversion in a group of size q is done by raising to the power q-2, so this is a matter of performing some multiplications). El Gamal is ...


8

Amazon claims that AWS VPC is "logically isolated" from the other AWS instances, and from the Internet. "Logically" means that it is done in software, not with dedicated hardware system. An AWS VPC can be connected to your VPN and it will use IPsec for that external connection, but this does not mean that internally IPsec is used. In fact, how the ...


8

If it is a catch-all address, they don't need the actual address. The entire point of a catch-all e-mail address is that it catches all mail that would otherwise be undeliverable. If you have thisIsMySuperSecretEmail@my-domain.com set as the catch-all, then if I sent an e-mail to bob@my-domain.com, you would get the message in the super secret mailbox ...


7

An example of practical use of PHE (and El Gamal in particular) is Helios Voting. With it you can publicly store encrypted voted ballots in the cloud, and also allow the public to both add them up to confirm the vote counts for each candidate, and to check that their own vote was indeed included in the total, without having a receipt that could prove how ...


7

Homomorphic encryption is a category of systems; some implementations might be weak, and others might be strong, but it doesn't make sense to talk of the entire category as "weak" or cryptanalyzable. Partially homomorphic cryptosystems (which used to be called just "homomorphic" before "fully homomorphic" cryptosystems were discovered) have been used in ...


7

Neither is necessarily more secure, but I will give you some opinions and perhaps facts. Host-extract can determine hostnames, which is also possible via virtual host enumeration. DirBuster, skipfish, and fuzzdb can rely on forced browsing, directory indexes, and predictable resource locations to find vulnerable directory structures and other issues. ...


7

From the ENISA pdf that @atdre already linked to in his answer. LOSS OF GOVERNANCE: in using cloud infrastructures, the client necessarily cedes control to the Cloud Provider (CP) on a number of issues which may affect security. At the same time, SLAs may not offer a commitment to provide such services on the part of the cloud provider, thus leaving a gap ...


7

Agree with Eric. Another point: DOS/DDOS are nasty attacks that relatively easy to make and hard to protect on application level. Think about what other option you have. Let’s say you will go to some other hosting provider and will get same attack, will it be better or worse? With Amazon at least you can be sure that you will continue to have service and ...


7

At 16-core GPU maximum, I'd build my own, unless oclHashcat can distribute work loads (at first look it doesn't seem like it does). That is assuming this thing is going to pound passwords all day most days. If you can scale it more (or want to run a lot in parallel) or wont use it all day long, pay for it by the hour. Now, after some sketching and brain ...


7

If you are already settled on using DropBox, then your only choice at the moment is to use a 3rd party program such as PGP (or free/open GPG) to first encrypt the file and place it into your drop box. I know you said you wanted to use public/private keys, but as an alternative, you could also use 7-zip to create secure archives with AES encryption based on ...


7

Sure it's possible. What you want to do is called Federation. How you set it up really depends on the applications and platforms you run though. There are a variety of protocols out there that can do what you want; e.g. SAML, WS-Federation, OpenAuth (to a degree), etc. The applications need to be able to support the federation protocols though. In theory ...


7

Consider this from an Information Management or Information Assurance question rather than an Information Protection question. To the question if a service provider's level of security is "safe" (sufficient and appropriate), the answer is YES and NO - depending on the level of protection the specific information requires. My suggestion is you create three ...


7

If the host is hostile then resistance is futile. The host can read the disk, RAM and CPU state of your VM. Only fully homomorphic encryption would save you, but it does not work yet (Science has not uncovered an efficient solution yet; but that's just a factor one billion or so, therefore we can still hope for something... later on).


7

The short answer is that when you put your data on the cloud the provider has the technical capability to do what they want with it. They could sell it, trade it, share it, etc. What is keeping them from doing just that is a) the terms of service or contract agreed (read it to make sure they don't have rights to your data as some claim rights over anything ...


6

A small subset of security issues (not necessarily new per se to cloud, but definitely more difficult) : Access control Privacy and confidentiality Availability (how strong is your SLA, really? does your provider indemnify for any damages resulting from being offline?) connection with internal systems - you'll often have to punch open holes in your ...


6

There was just a blog post from Lenny Zeltser on this topic: Top 10 Cloud Security Risks Most of his points talk about the problem that you don't have full control over the infrastructure anymore, and might not even know how it works internally. One also doesn't know anymore who else is on the same system, and a vulnerability in their system might leak over ...



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