To protect their psychological health and to be free citizens, people need to encrypt their electronic communication.
“Once we know there’s a reasonable chance that we are being watched in one fashion or another it’s hard for that not to have a ‘panopticon effect' where we think and behave differently based on the assumption that people may be watching and paying attention to what we are doing.”
The mass of electronic surveillance details revealed by the CIA analyst and private contractor Edward Snowden in 2013 establish one indubitable fact: the NSA in the US, and GCHQ in Britain, want access to all diplomatic, commercial and private electronic data from their own countries and from the rest of the world. To that end, they have built facilities that hoover up electronic data in transit; they have hacked into telephone networks and in some cases have planted spyware into computers. If the correspondence of the average citizen - the recipes, shopping lists and notes to granny - are not sorted and stored, it is only because the spooks have decided not to retain it. Yet the mere fact that what one expects to be private is not private at all has deep psychological implications for the average citizen. We browse the net for private information and stimulation, and we communicate electronically for a myriad of purposes: writing love letters, talking honestly with friends about our workplaces, neighbours and teachers. Our surveilled data, even if of no interest to the spooks, lies copied on several servers with the danger of it falling victim to malicious hacking multiplied.
However, for people who are, were, or might wish in the future to be active politically, the damage is more immediately felt. If we take the now established fact that British police have over the last few decades embedded over 1200 long term double-life spies in civic organisations at a cost of millions of pounds each year, it would be absurd to assume that the much cheaper practice of collecting, sorting and storing the electronic communication of those who engage in politics is not endemic.
The law governing surveillance offers little protection. The fact is that by one means or another our data can become available to the institutions of the state. Only when the state needs to make public that it has our data (e.g. for a prosecution) does the issue of the legality of the state possessing it in the first place arise. It is thus reasonable to believe that the annual two and half million requests by police to access our data legally is only the tip of the iceberg - or the icing on the cake - of surveillance.
And who is targeted, legally or otherwise? Today, it is reasonable to think that at the very least the members of the Green Party and now Jeremy Corbyn and his supporters in the Labour Party, as well as host of other campaigning groups, are under active surveillance - along with all those who campaigned for Scottish independence. Indeed, there are documented cases of police surveillance of people in these legal and democratic organisations.
Yet citizens do not stand completely naked before the state. And if one wants privacy, be it a matter of principle, for psychological health, or to campaign for political goals with as little state surveillance and impediment as possible, then people need to encrypt their data and communication. David Cameron has gone on record saying he wants to outlaw encryption for which the state does not have a backdoor, but without the help of the US, that is a non-starter.
When Alice sends an email to Bob the email travels through cables and is then stored in servers at Google, Yahoo or wherever. Scanning it at any point takes a microsecond, so the content is simply there for the taking. And until recently that was all the spooks had to do, but with the rise of https (the green text and the padlock icon), used by Google, Facebook and others, the content is encrypted between the user's browser and the service provider. But we can’t be sure that the spooks don’t have a backdoor to the encryption, that the service provider doesn’t hand over content, maybe unwillingly, or that the storage facilities have not been hacked or corrupted in some way.
But if Alice encrypts her email before it even leaves her computer with open-source algorithms and keys which are under the control of her and the recipient, the spooks are stymied. Hence Cameron’s concern. What is intercepted or stored on the service provider’s server is indecipherable. Alice and Bob can do this by using encryption software on their computers, such as PGP - or they can use web-based end-to-end encryption services, such as ProtonMail or Tutanota - or, of course, both in conjunction.
All that leaves the spooks with only one option: to hack your computer. Unless you take several complicated precautions they can probably do this, but they must want to target you personally as an important person because they will need to devote time an effort to the job. In other words the cost to the spooks of surveillance increases exponentially and the number of people (if they use encryption) that they can monitor falls dramatically. And even then their surveillance is not fully effective because you might be using several devices. So unless the state is really after you, the encryption of your communication and stored data is probably enough to maintain your privacy.
So fight for your privacy and encrypt.
Showing posts with label encryption. Show all posts
Showing posts with label encryption. Show all posts
3 October 2015
20 September 2015
The case for symmetric encryption
There are circumstances when symmetrical encryption, that is where both sender and recipient use the same secret key to encrypt and decrypt messages, is the most practical and safest method for encrypting email.
Whenever a message sender, who is known by cryptographic custom as Alice, wishes to write an end-to-end encrypted email to a recipient, customarily known as Bob, one of two cryptographic systems can be used.
The simpler is symmetric encryption in which Alice and Bob have a single secret key, which is used by both of them to encrypt and decrypt messages. The obvious shortcoming of symmetrical encryption is that before Alice and Bob can email, they need to meet up – or have some other safe channel – through which to communicate the secret key. Asymmetrical encryption solves that problem. Both Alice and Bob have two mathematically related keys, one private one public. For Alice to send Bob an encrypted message she ascertains his public key and encrypts her message using it. The message can only be decrypted using Bob's private key, which he keeps secret and safe.
It would seem, then, that asymmetrical encryption, involving no prior secret exchange of keys, enjoys a clear advantage, and for many purposes it does. But there are a number of things that can go wrong with asymmetrical encryption, which can't happen with symmetrical encryption – or at least can’t happen when the secret symmetric key is agreed face-to-face. Let us look at what can screw up with asymmetric encryption:
1. Alice is sending Bob a message encrypted with Bob's public key. However she needs to authenticate it; i.e. prove the message is from her. Precisely because Bob's public key is public anybody could encrypt a message using it and then impersonate Alice. To prevent that, Alice “signs” the message using her own private key. To decrypt the message Bob uses his private key; and to verify the authenticity of the message he needs Alice's public key. The difficulty is solved, but only at the expense of complexity. With symmetric encryption signing and verification are not necessary because the ability to encrypt and decrypt using the single secret key is proof of authenticity.
2. Before Alice can email Bob she needs to find Bob's public key, which may be on his website or in some other public place. But how can Alice be sure that the website or key server has not been tampered with, and that she is not encrypting the message with a key that can be read by somebody else? Equally, when Bob needs to find Alice's public key from a public place to verify the message, how can he know it is genuine? If Alice and Bob had agreed a symmetric key face-to-face the issue of tampering and impersonation would not arise.
3. It could happen that Alice or Bob believe that their private key is no longer secret and safe. If someone else had acquired it, all his or her incoming mail could be read, but revoking the key from a public place is not easy. To be successful, everyone who has or might use it needs to know of the revocation and of the replacement. With symmetric encryption, compromising one key only affects the two parties involved; they can then easily set up a new key – and maintain different levels of security for each key used with different people. Alice's communication with Bob can be kept more securely than her communication with Bill, for instance.
Asymmetric public key encryption therefore brings with it a number of difficulties not suffered by symmetric encryption. The sole disadvantage of symmetric encryption is that Alice and Bob need to agree a secret key face-to-face or through some other safe channel. But in many cases that it is no difficulty at all. It may well be that Alice and Bob meet in person as well as send emails. Alice and Bob could be lovers, or they could be members of a political action group which is under surveillance by security agencies. There is no safer form of email encryption than for Alice and Bob to meet, agree a twenty-character long password consisting of random numbers and letters, and for both of them to keep it secret and safe and to use it to encrypt and decrypt their text emails.
Whenever a message sender, who is known by cryptographic custom as Alice, wishes to write an end-to-end encrypted email to a recipient, customarily known as Bob, one of two cryptographic systems can be used.
The simpler is symmetric encryption in which Alice and Bob have a single secret key, which is used by both of them to encrypt and decrypt messages. The obvious shortcoming of symmetrical encryption is that before Alice and Bob can email, they need to meet up – or have some other safe channel – through which to communicate the secret key. Asymmetrical encryption solves that problem. Both Alice and Bob have two mathematically related keys, one private one public. For Alice to send Bob an encrypted message she ascertains his public key and encrypts her message using it. The message can only be decrypted using Bob's private key, which he keeps secret and safe.
It would seem, then, that asymmetrical encryption, involving no prior secret exchange of keys, enjoys a clear advantage, and for many purposes it does. But there are a number of things that can go wrong with asymmetrical encryption, which can't happen with symmetrical encryption – or at least can’t happen when the secret symmetric key is agreed face-to-face. Let us look at what can screw up with asymmetric encryption:
1. Alice is sending Bob a message encrypted with Bob's public key. However she needs to authenticate it; i.e. prove the message is from her. Precisely because Bob's public key is public anybody could encrypt a message using it and then impersonate Alice. To prevent that, Alice “signs” the message using her own private key. To decrypt the message Bob uses his private key; and to verify the authenticity of the message he needs Alice's public key. The difficulty is solved, but only at the expense of complexity. With symmetric encryption signing and verification are not necessary because the ability to encrypt and decrypt using the single secret key is proof of authenticity.
2. Before Alice can email Bob she needs to find Bob's public key, which may be on his website or in some other public place. But how can Alice be sure that the website or key server has not been tampered with, and that she is not encrypting the message with a key that can be read by somebody else? Equally, when Bob needs to find Alice's public key from a public place to verify the message, how can he know it is genuine? If Alice and Bob had agreed a symmetric key face-to-face the issue of tampering and impersonation would not arise.
3. It could happen that Alice or Bob believe that their private key is no longer secret and safe. If someone else had acquired it, all his or her incoming mail could be read, but revoking the key from a public place is not easy. To be successful, everyone who has or might use it needs to know of the revocation and of the replacement. With symmetric encryption, compromising one key only affects the two parties involved; they can then easily set up a new key – and maintain different levels of security for each key used with different people. Alice's communication with Bob can be kept more securely than her communication with Bill, for instance.
Asymmetric public key encryption therefore brings with it a number of difficulties not suffered by symmetric encryption. The sole disadvantage of symmetric encryption is that Alice and Bob need to agree a secret key face-to-face or through some other safe channel. But in many cases that it is no difficulty at all. It may well be that Alice and Bob meet in person as well as send emails. Alice and Bob could be lovers, or they could be members of a political action group which is under surveillance by security agencies. There is no safer form of email encryption than for Alice and Bob to meet, agree a twenty-character long password consisting of random numbers and letters, and for both of them to keep it secret and safe and to use it to encrypt and decrypt their text emails.
7 February 2015
Cameron wants to outlaw encrypted messaging
David Cameron’s desire, however impractical, to outlaw the citizen’s use of end-to end encryption to enable the security services to view every private communication is a an assault on freedom.
Events in Paris on 7 January 2015 were truly horrific. Two marginalised and alienated people - armed with guns and a Muslim-inspired fascist ideology - went on a rampage of murder in the offices of the Charlie Hebdo magazine. France and the world were rightly outraged.
In Britain, cashing in the terror, David Cameron took his chance to push for a ban on end-to-end encryption, even though the terrorists in France never used encryption. End-to-end encryption is the means by which you encrypt a message on your own computer and send the message to someone else who decrypts it on his or hers. GCHQ and the NSA can’t read the data either in transit or from the internet giants’ servers. Apple’s new iphone and several messaging apps do the same thing.
In fact, you can get a small file which enables end-to-end text encryption here.
In his speech Cameron asked, “...in our country, do we want to allow a means of communication between people which we cannot read?” Well, yes we do. It is not just a matter of a fundamental right of people to be able to talk and write to one another without the security services reading and listening, but we know full well that state snooping of private correspondence is used to impede legitimate political activity by ordinary people.
Cameron and his government are a far greater threat to freedom than a handful of fanatical killers in Paris.
Events in Paris on 7 January 2015 were truly horrific. Two marginalised and alienated people - armed with guns and a Muslim-inspired fascist ideology - went on a rampage of murder in the offices of the Charlie Hebdo magazine. France and the world were rightly outraged.
In Britain, cashing in the terror, David Cameron took his chance to push for a ban on end-to-end encryption, even though the terrorists in France never used encryption. End-to-end encryption is the means by which you encrypt a message on your own computer and send the message to someone else who decrypts it on his or hers. GCHQ and the NSA can’t read the data either in transit or from the internet giants’ servers. Apple’s new iphone and several messaging apps do the same thing.
In fact, you can get a small file which enables end-to-end text encryption here.
In his speech Cameron asked, “...in our country, do we want to allow a means of communication between people which we cannot read?” Well, yes we do. It is not just a matter of a fundamental right of people to be able to talk and write to one another without the security services reading and listening, but we know full well that state snooping of private correspondence is used to impede legitimate political activity by ordinary people.
Cameron and his government are a far greater threat to freedom than a handful of fanatical killers in Paris.
1 February 2015
Britain's war on investigative journalism
Free journalism is the last remaining source of opposition in Britain. That is why the state ranks journalists alongside terrorists as a threat.
With the demise of mass progressive organisations in the last few decades, one of the few remaining sources of critique of the existing political order is the writing of journalists. So today, it is the likes of Glenn Greenwald and George Monbiot who carry the torch of political opposition, rather than politicians.
It is hardly surprising that, according to documents from the Snowden cache, GCHQ in Britain ranks investigative journalists alongside terrorists and hackers as targets worthy of surveillance. In a single trawl in 2008 GCHQ harvested around 70 000 emails from journalists working for the BBC, Reuters, the Guardian, the New York Times, Le Monde, the Sun, NBC and the Washington Post. The results were placed on the GCHQ intranet for analysis by agents.
The mass hoovering up of electronic communication by the security agencies is now an established fact. The legality of doing so only comes into a play when some of these ill-gotten fruits of mass surveillance need to be brought into the public domain, such as for a court case. To this end, in Britain the state uses RIPA, Regulation of Investigatory Powers Act 2000, which inter alia empowers police to access journalists’ electronic communication without a court order with only the approval of senior officers. Just to take two instances: In the so-called Plebgate affair, police used RIPA powers to access the phone records of a journalist working for the Sun; and the records of a Mail on Sunday journalist were similarly acquired in the Chris Huhne speeding affair. Neither case involved terrorism or serious crime.
Investigative journalism remains one the last means of critiquing political power in Britain. It is under attack, and one small step of resistance is to achieve secure communication by encrypting phone speech and email, end-to-end. Of course that does nothing to hide the metadata - who’s contacting whom, when and for how long - but it shuts GCHQ and the police out of the content. David Cameron doesn’t like that, and that’s why he would like to ban it.
With the demise of mass progressive organisations in the last few decades, one of the few remaining sources of critique of the existing political order is the writing of journalists. So today, it is the likes of Glenn Greenwald and George Monbiot who carry the torch of political opposition, rather than politicians.
It is hardly surprising that, according to documents from the Snowden cache, GCHQ in Britain ranks investigative journalists alongside terrorists and hackers as targets worthy of surveillance. In a single trawl in 2008 GCHQ harvested around 70 000 emails from journalists working for the BBC, Reuters, the Guardian, the New York Times, Le Monde, the Sun, NBC and the Washington Post. The results were placed on the GCHQ intranet for analysis by agents.
The mass hoovering up of electronic communication by the security agencies is now an established fact. The legality of doing so only comes into a play when some of these ill-gotten fruits of mass surveillance need to be brought into the public domain, such as for a court case. To this end, in Britain the state uses RIPA, Regulation of Investigatory Powers Act 2000, which inter alia empowers police to access journalists’ electronic communication without a court order with only the approval of senior officers. Just to take two instances: In the so-called Plebgate affair, police used RIPA powers to access the phone records of a journalist working for the Sun; and the records of a Mail on Sunday journalist were similarly acquired in the Chris Huhne speeding affair. Neither case involved terrorism or serious crime.
Investigative journalism remains one the last means of critiquing political power in Britain. It is under attack, and one small step of resistance is to achieve secure communication by encrypting phone speech and email, end-to-end. Of course that does nothing to hide the metadata - who’s contacting whom, when and for how long - but it shuts GCHQ and the police out of the content. David Cameron doesn’t like that, and that’s why he would like to ban it.
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