Consider a block-cipher $F$ with a $N$-bit block-size and a $M$-bit key-size. That is, if $k$ is a $M$-bit key, $p$ is a $N$-bit block of plain-text and $c$ is a $N$-bit block of cipher-text, then: ...
Looking at the first step of AES encryption I see that we XOR the key with the plaintext block. Why is the actual key involved at all, why not just use the round keys derived from the key schedule?
Does the order of a block cipher cascade (e.g. in TrueCrypt) make a difference to the security provided, assuming independant keys? For example: ...
I'm working with a server/client system that has securely negotiated a private key. I need to encrypt/decrypt messages passing in both directions which are typically between 100 bytes to 100 KB. I'm ...