You do not need to know the details of the "classical" techniques such as the Caesar Cipher or Rotor Machines, but you do need to understand the cryptanalytic attacks based on relative frequency described on pp. 33-37. Know the One-Time Pad technique (pp. 43-44) and its advantages and disadvantages.

Know the entire contents of Section 3.2, including the difference between stream and block ciphers and the techniques of diffusion and confusion. Know the structure of the Feistel Cipher, and be able to list the parameters that might vary between encryption algorithms (p. 69).

Understand the structure of DES (Figure 3.7) and be able to describe its external features (e.g., key size, plaintext block size, number of rounds). Make sure that you understand the Avalanche Effect in general, not just for DES. Read Section 3.4 completely, understand why DES is obsolete, and understand the idea of a timing attack.

Read Section 3.5 and make sure that you understand the basic ideas of Differential and Linear Cryptanalysis. Know that Differential Cryptanalysis is based on the idea that watching how changes to the plaintext affect the value of the ciphertext might allow you to make conclusions about the key, and that Linear Cryptanalysis attempts to find linear approximations to the transformations performed by the cipher.

Know each of the design criteria described in Section 3.6, and be able to describe them. (For example, what makes for a good S-box?). Know each of the block cipher modes in Section 3.7 and their characteristics, specifically Table 3.6.

Section 6.4 should be largely a review of parts of Section 3.2. Understand the possibilities for variation of the basic Feistel structure.

In Section 7.3, Understand the problems posed by key distribution, the options for delivering keys, the idea of session keys, and of a KDC and key hierarchy (pp. 211-214). Understand how the lifetime of a session key affects its security (p. 216). Understand the issues addressed in the key distribution scenarios on pp. 214-215 and 217-218, and what a nonce is used for.

In Section 9.2, you really just need to understand that the RSA encryption algorithm consists of taking the plaintext to a power, and that the decryption function is just taking the cryptext to a different power, and that the exponents are chosen to be related in such a way that the operations are yield the same value. Understand the requirements listed at the top of p. 269, and the possible avenues of attack described on pp. 274-278.

Diffie-Hellman Key Exchange is the one public-key algorithm straightforward enough that you should be able to memorize its derivation (bottom of p. 294, or Figure 10.7)

You do not need to know the internals of the algorithms (i.e., the subsections "MD5 Logic" and "MD5 Compression Function" and the corresponding sections for SHA-1), nor do you need to know anything about MD4.

You need to understand the idea of an HMAC (pp. 372 and 373) and why you would need an HMAC instead of a hash function (e.g., to avoid man-in-the-middle attacks), but you do not need to know the implementation details.

In Section 13.2, understand the replay attacks described in Section 13.2 (p. 384) and the approaches for coping with them (p. 385).