One of them, Scream-F, reuses the S-boxes from the Advanced Encryption Standard (AES) block cipher, while the other, Scream, internally generates new, key-dependent S-boxes as part of the initialization phase. The round function is also based on the AES-round function, but is narrower, 64 bits instead of 128 bits.
One of the algorithms, Scream-F, utilizes pre-existing S-boxes from the Advanced Encryption Standard (AES) block cipher, while the other, Scream, generates its own S-boxes dynamically during initialization based on the key. The round function is derived from AES but has a reduced width, operating with 64 bits instead of 128 bits.