Dvdes-631

puts(flag);

user_key = rotr64(sub_0 ^ magic, 1)

cur_0 = user_key cur_i+1 = rotl64(cur_i, i+1) ^ magic sub_i = cur_i+1 dvdes-631

// 2) Derive 16 sub‑keys (the “631” hint) uint64_t sub[16]; uint64_t cur = key; for (int i = 0; i < 16; ++i) // Rotate left by i+1 bits, then XOR with magic cur = rotl64(cur, i + 1) ^ magic; sub[i] = cur; puts(flag); user_key = rotr64(sub_0 ^ magic, 1) cur_0