Address-dependent key generator by XOR tree

A system for providing security in a computer system, the system comprising one or more logic circuits configured to at least:

• receive a respective address of a memory location in a memory;
• produce a plurality of sub-keys from random key material and based on random key material and based on the respective address, the plurality of sub-keys being a plurality of blocks of random numbers;
• mix the plurality of sub-keys together to produce an intermediate result, the plurality of sub-keys being mixed using a binary tree of multiple levels of bitwise exclusive-or operations;
• perform a scrambling operation on the intermediate result to produce a key;
• produce a block of ciphertext with the key;
• and
• perform a write operation to write the block of ciphertext at the memory location having the respective address,
• wherein the memory includes a window of memory locations each of which stores a respective block of ciphertext produced with a respective key that changes from memory location to memory location, the key is produced further based on a version value that is updated with each write operation at the memory location having the respective address, and each memory location of the window of memory locations stores the respective block of ciphertext produced with the respective key that also depends on the version value and thereby changes with each write operation,
• wherein the respective address and version value are composed of respective sub-sequences of bits that concatenated form a sequence of bits at respective bit positions, and the random key material is composed of a sequence of blocks of random numbers at respective block positions, and
• wherein the one or more logic circuits being configured to produce the plurality of sub-keys includes being configured to produce the plurality of sub-keys further from the version value, including the one or more logic circuits being configured to identify a plurality of bits from the sequence of bits, and select the plurality of blocks from the sequence of blocks at respective positions corresponding to those of the plurality of bits, the plurality of blocks being selected as the plurality of sub-keys.