Consider the following scenarios:
- using OpenSSL to encrypt a file with Rijndael-256
- using LUKS to encrypt a hard-drive that is used every day
Exactly when is entropy from
/dev/random needed for a crypto process?
Is it only needed for the key generation or is it also needed for the encryption process itself?
When the CPU is executing a crypto process (key generation or encryption) for a program, does the CPU cause some kind of pattern (like a fingerprint of the encrypted data) as it processes? Can this "processing pattern" then be used to break the encryption and see the plaintext?