Step 1 - Unmount and Wipe Existing Partition
sudo umount /mnt/storage
sudo wipefs -a /dev/sdb


Step 2 - Partition the First 30GB or as much as you want to use i have a 128gb sd 

we'll use fdisk
sudo fdisk /dev/sdb


Inside fdisk, enter the following commands:

    g - create a new GPT partition table (or o for MBR)

    n -  new partition

    Partition number: 1

    First sector: press Enter

    Last sector: +30G

    t - change type, enter 83 for Linux (or a nonstandard type like 30 if you want stealth)

    w - write and quit


Step 3 - Zero the Start of the Partition (optional for stealth)

sudo dd if=/dev/zero of=/dev/sdb1 bs=1M count=10 status=progress

Step 4 - Encrypt with LUKS2 & AES-256

sudo cryptsetup luksFormat /dev/sdb1 --type luks2 \
  --cipher aes-xts-plain64 --key-size 512 --hash sha512

(enter YES when prompted and set your passphrase. 

Step 5 - Open And Format

sudo cryptsetup open /dev/sdb1 hidden_storage
sudo mkfs.ext4 /dev/mapper/hidden_storage


Step 6 - Mount Manually (Keep Hidden)

sudo mkdir -p /mnt/hidden_storage
sudo mount /dev/mapper/hidden_storage /mnt/hidden_storage

Step 7 -  To Unmount and Lock

sudo umount /mnt/hidden_storage
sudo cryptsetup close hidden_storage



>>>>>>> now thats pretty much it for the hidden partition copy and close files securely .But If you want to use the rest of the SD card (e.g., for regular storage or even a decoy), 
you can. Let me show you how.

1 - sudo fdisk /dev/sdb

In fdisk:

    n -  new partition (it will be sdb2)

    Accept default start sector (should begin right after sdb1)

    End sector: press Enter to use all remaining space

    w to write

2 - Format sdb2 

sudo mkfs.ext4 /dev/sdb2

3 - Mount it

sudo mkdir -p /mnt/decoy_storage
sudo mount /dev/sdb2 /mnt/decoy_storage


| Partition   | Use              | Mount Point           |
| ----------- | ---------------- | --------------------- |
| `/dev/sdb1` | Hidden encrypted | `/mnt/hidden_storage` |
| `/dev/sdb2` | Normal or decoy  | `/mnt/decoy_storage`  |




>>>> Cleanup and Safety

    To lock the encrypted partition:
    
    sudo umount /mnt/hidden_storage
    sudo cryptsetup close hidden_storage

    To Remount Later:
    sudo cryptsetup open /dev/sdb1 hidden_storage
    sudo mount /dev/mapper/hidden_storage /mnt/hidden_storage




{and violaa thats its enjoy and stay safe.}