Perfect Paper Passwords - Two-Factor Authentication for the Masses

Usernames and passwords have long been established as the de facto form of authentication for websites and other systems. They provide a convenient system for authenticating and identifying users. However, they are also highly vulnerable to dictionary attacks, weak passwords, key-loggers etc. Recently, two-factor authentication has been suggested as providing a much stronger approach. In addition to 'Something You Know', such as a password, you also provide 'Something You Have', such as a security token. Verisign and RSA Security offer such products that produce a time-synchronized sequence of digits that change at regular intervals. Systems that incorporate these security token mechanisms, accept the sequence of digits in addition to a password during authentication.

Steve Gibson from GRC recently released a similar system based on passcodes. The Perfect Paper Passwords system produces a set of one-time passcodes. The passcodes are created using a 256-bit Sequence Key passed through a Rijndael/AES Cipher. The passcodes are then grouped into credit card sized passcards across 7 columns and 10 rows. During authentication, the system would prompt the user to enter the passcode at a particular column-row location (e.g. A3, D8 etc.). Since the passcards can be printed on paper it is an inexpensive, simple and highly-effective method of providing two-factor authentication.

The system has been released freely for public use and there are a number of language specific implementations already in place. Based on the sheer number of possible combinations, the PPP system is 16.77 times more secure than the token based systems by Verisign and RSA Security!

Secure Email Attachments with TrueCrypt

Digital documents have finally come of age. We now increasingly receive our bank statements, insurance quotes and receipts as digital files such as Word or PDF. Also, there is often a need to attach these documents to an email. Securing these attachments in transit over the Internet is an immediate concern. There are a number of solutions available such as Hushmail, a secure free email provider and PGP Desktop Email, a commercial email encryption product. The solution that I discuss here is based on a free, open-source encryption software called Truecrypt.

Truecrypt makes using bullet-proof encryption really easy through the concept of virtual encrypted disks. Each disk is stored as a single encrypted file and can be mounted as a real disk. Once mounted, it can be used as a local drive on the system. Entire hard-drives or USB memory sticks can be encrypted as well. Volumes can be protected using a password or through key files. Any file on the system can be used as a key file as an alternative or in addition to using a password. The key file or sequence of key files is required to encrypt and decrypt the disk.

The concept of key files makes using Truecrypt really valuable while sending sensitive attachments over email. In addition to using a password, if the sender and the receiver agree on a common file or a sequence of files that are uniquely present on both systems such as digital photographs or video clips, the encryption can be made highly secure. Hence the encrypted attachments are useless if intercepted during transit without the key files.

Truecrypt is extremely simple to use and hence there is just no excuse for not securing confidential files on storage or in transit.