Disc Image Encryption

Open Burning Suite supports AES-256-CBC encryption and decryption for disc image files, allowing you to protect sensitive backups with a password.

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OBS Encrypted Format (.obse)

Encrypted images use the .obse (Open Burning Suite Encrypted) extension with the following header structure:

Offset	Size	Field
0	4 bytes	Magic: OBSE
4	2 bytes	Format version (0x0001)
6	2 bytes	KDF iteration exponent (iterations = 2^value, min 65536)
8	32 bytes	PBKDF2 salt
40	16 bytes	AES-256-CBC initialization vector (IV)
56	32 bytes	HMAC-SHA256 of encrypted payload
88	8 bytes	Original file size (little-endian uint64)
96	N bytes	AES-256-CBC encrypted payload (PKCS7 padded)

Total header: 96 bytes before encrypted payload.

Security features:

• AES-256-CBC symmetric encryption
• PBKDF2 key derivation (RFC 8018) with configurable iteration count
• HMAC-SHA256 integrity verification
• Unique random salt and IV per encryption
• Cross-platform (uses only .NET built-in System.Security.Cryptography)

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Encrypting an Image

To encrypt a disc image before burning:

1. Go to Burn / Write view
2. Select your source image file
3. Enable the encryption option in the burn panel
4. Enter and confirm a strong password
5. The application creates an .obse file with the encrypted image
6. Proceed to burn the encrypted image to disc

Note: Encrypting increases burn time due to the encryption pass. The original image is not modified.

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Decrypting an Image

When you select an .obse file for burning:

1. The application detects the encrypted format automatically
2. You are prompted to enter the decryption password
3. The image is decrypted in memory and burned to disc
4. The original .obse file remains unchanged

PS3 Image Decryption

PlayStation 3 ISO images can be decrypted before burning using one of three key sources:

Key Source	File Extension	Description
IRD file	.ird	Official IRD file containing the disc key (versions 6–9 supported)
Disc key file	.dkey	Plaintext disc key file
Hex disc key	—	32-character hex string pasted directly

The decryption panel appears automatically when a PS3 ISO is detected. The service uses AES-128-CBC with per-sector IV for sector-level decryption.

PS3 Encryption Reference:

• Sector size: 2048 bytes
• AES-128-CBC with per-sector IV
• IV = 16-byte array with sector number in last 8 bytes (big-endian)
• Odd-numbered regions: encrypted
• Even-numbered regions: unencrypted
• Region map: stored in sector 0 of the ISO
• Disc key derived from IRD Data1 field using AES-128-CBC with fixed key/IV

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