A Practical Guide to Trusted Computing

Chapter 9

Using Symmetric Keys

The TPM provides an excellent facility to create, store, and manage asymmetric keys, but when it comes time to encrypt large amounts of data, using the TPM may not be as obvious. Due to the speed of operations for asymmetric cryptography, it is not well suited for this task. This is where symmetric cryptography steps in to handle the load. Symmetric algorithms such as Triple-DES, AES, and Blowfish are many times faster for encryption and decryption, making them ideal to provide confidentiality for large amounts of data.

Although the TPM has no native support for symmetric encryption, it can play an important role in providing a secure way to store, use, and transport symmetric keys. Binding or sealing symmetric ...