Would you lock your front door and leave the key under the mat? So why do you do it with digital keys?

Where I live it is Island Mentality. Someone said to me that they do not lock their front door. Sometimes, when they come home, they find some eggs or tray-bakes on the kitchen table. They went on a celebration cruise, but could not find the key to the front door, and so left the house unlocked the two weeks they were away.

Digital certificates and keys are used for identification authentication. Often these are stored in a key store, just a file in Windows or Unix. You typically need a password to be able to read the file. If you got hold of a keystore, you could try “password” with an “o”, “passw0rd” with zero etc. There is no limit to the number of attempts you can have. Don’t worry, the password is stored in a stash file , which is just another file. If you have the key store and the stash file you can open the keystore using standard commands. Having both the keystore and the stash file is like finding the front door unlocked.

If someone is an administrator on the machine, they can access any file and so can get the keystore and the stash file. IBM says you need superuser access to install MQ – so the MQ administrator can access these files. I heard that one enterprise was doing backups from the user’s machines to a remote site. The files were encrypted at the remote site, but not the network link to the remote site – whoops! The files could have been stolen en route.

Use external security devices.

You can get round this problem by using an external Hardware Security Module. Instead of storing the keys in a file, they are stored on an external device. You can get USB like devices. Some HSM can store keys, other HSMs can encrypt data. For example my bank gives its user’s a small machine. You put in your debit card, enter your pin. It encrypts the data and generates a one time key which you enter into the bank’s web site.

To steal the keystore you now need access to the physical machine to be able to unplug the USB.

Built in devices that cannot be removed.

On some machines, such as z hardware, they have a tamper resistant “cryptographic chip” built in. If you remove it from the machine, it is useless. When you configure it you need three keys, so you have three people each with their own key. When you install the backup machine, the three people have to go on site, and re enter their keys. They have mechanisms like three wrong passwords and it self destructs (perhaps in a cloud of smoke, as it does in the movies).

“Cloud”

One of the selling points of cloud is flexibility. You can deploy an image anywhere; you can wheel in new machines, and wheel out old machines; and you can have different “tenants” on the same hardware. This makes it difficult to use an HSM device to store your keys, as each machine needs the same keys, and the HSM could have all the keys from all the tenants. So you have the problem, of having your key store as a file with its stash file, and even more people have access to these files.

Would you lock your front door and leave the key under the mat? So why do you do it with digital keys

It is all down to the management of risk. Digital certificates do not give absolute protection. Strong encryption just means it takes longer to crack!

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