Chapter 8

Secret and Public Keys

FIGURE 8.0.F01: Using a passphrase for a file encryption key.

FIGURE 8.0.F02: Hashing a passphrase for a file encryption key.

FIGURE 8.0.F03: Reusing the same key stream.

Courtesy of Dr. Richard Smith

FIGURE 8.0.F04: Eliminating both key streams with “xor.”

Courtesy of Dr. Richard Smith

FIGURE 8.0.F05: Using a nonce to construct the encryption key.

FIGURE 8.0.F06: Wrapping a key: The KEK encrypts the CEK.

FIGURE 8.0.F07: Key splitting with xor.

FIGURE 8.0.F08: Separation of Duty for an early nuclear missile.

Photographed by Dr. Richard Smith at the Titan Missile Museum

FIGURE 8.0.F09: Keys on the DVD hidden track.

FIGURE 8.0.F10: Decrypting a DVD sector.

FIGURE 8.0.F11: Public-key encryption.

FIGURE 8.0.F12: Constructing the public/private key pair.

TABLE 8.0.T01: Comparison of secret-key and public-key crypto

FIGURE 8.0.F13: Asymmetric encryption algorithms.

FIGURE 8.0.F14: Procedure for Diffie-Hellman secret sharing.

EQUATION 8.0.Eq01

EQUATION 8.0.Eq02

EQUATION 8.0.Eq03

FIGURE 8.0.F15: Encapsulating a key with Alice’s RSA public key.

FIGURE 8.0.F16: Retrieving the key with Alice’s RSA private key.

FIGURE 8.0.F17: Constructing an RSA key pair.

EQUATION 8.0.Eq04

TABLE 8.0.T02: Comparable Key Sizes

FIGURE 8.0.F18: Bit-flipping attack on encryption with xor.

FIGURE 8.0.F19: Data encrypted with its checksum.

FIGURE 8.0.F20: An IOU with an adjustable check value.

EQUATION 8.0.Eq05

FIGURE 8.0.F21: Encrypting a hash: two steps.

FIGURE 8.0.F22: Keying a hash: one step.

FIGURE 8.0.F23: Signing a check with a digital signature.

FIGURE 8.0.F24: Constructing an RSA digital signature.

FIGURE 8.0.F25: Verifying an RSA digital signature.

FIGURE 8.0.F26: Eve performs a bucket brigade attack.

FIGURE 8.0.F27: Constructing a public-key certificate for Alice.

FIGURE 8.0.F28: Checking a certificate chain.

FIGURE 8.0.F29: A certificate hierarchy that spans multiple enterprises.

FIGURE 8.0.F30: A web of trust.

FIGURE 8.0.F31: Procedure for verifying a software update.

FIGURE 8.0.F32: A set of processes for trusted software update.

FIGURE 8.0.F33: Little brother’s encryption program.