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My understanding is that the cipher's encryption: Performs a fixed public reversible transformation of the first 128 bytes of plaintext. Enciphers the first 8 bytes $[B_0…B_7]$ with $K_1$, $K_2$, then $K_3$ Enciphers bytes $[B_{4+8i}…B_{11+8i}]$ with $K_1$ Enciphers bytes $[B_{2+8i}…B_{9+8i}]$ with $K_2$ Enciphers bytes $[B_{1+8i}…B_{8+8i}]$ with $K_3$ The ...

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I guess you are referring to this whitepaper, so I will refer to it in my answer. First, I think you misunderstood part of the protocol (illustrated in Figure 1): the KDF is not AES-CFB8. A KDF is a Key Derivation Function: in this particular case, it basically acts as a hash function, transforming the inputs into a random-like stream of bytes We assume the ...

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How the PPCBC mode works Propagating Cipher Block Chaining mode of operation (PCBC) works as with message indexes starts from 1; For PCBC encryption we have; $$C_i = E_K(P_i \oplus P_{i-1}\oplus C_{i-1})\text{ and } \color{red}{C_0 = P_0 \oplus IV}$$ For PCBC decryption ve have; P_i = D_K(C_i) \oplus P_{i-1}\oplus C_{i-1}\text{ and } \color{red}{C_0 = ...

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In cryptographic operation modes that require the initialization vector to be non-repeated rather than random, the initialization vector is called "nonce" (number used once). Do not design the implementation of a mode if you cannot fulfill the requirements of the mode. For example, if a mode depends on a uniqueness of the initialization vector, you ...

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