Decryption doesn't seem to work

[rmsimpson]

Tried reading an encrypted volume, code didn't work, wrong IV. AES256

apfsutil: Parameters of APFS->le:
apfsutil: === Main superblock header ======
apfsutil: Magic [NXSB]  : NXSB
apfsutil: Version       : 2 (macOS 10.13)
apfsutil: Checkpoint id : 0x5a, next: 0x5b
apfsutil: Total blocks  : 0xfff6, ro
apfsutil: BlockSize     : 0x1000
apfsutil: Current SB    : 0x2 + 2
apfsutil: SB area       : 0x1 + 0x8, next: 0x4
apfsutil: Meta area     : 0x9 + 0x14c, next: 0x5d
apfsutil: CSB map       : 0x3
apfsutil: Volume root   : 0xf89f
apfsutil: KeyBag        : 0x17d + 0x1
apfsutil: =====================================
apfsutil: === Last checkpoint superblock header ======
apfsutil: Magic [NXSB]  : NXSB
apfsutil: Version       : 2 (macOS 10.13)
apfsutil: Checkpoint id : 0x5a, next: 0x5b
apfsutil: Total blocks  : 0xfff6, ro
apfsutil: BlockSize     : 0x1000
apfsutil: Current SB    : 0x2 + 2
apfsutil: SB area       : 0x1 + 0x8, next: 0x4
apfsutil: Meta area     : 0x9 + 0x14c, next: 0x5d
apfsutil: CSB map       : 0x3
apfsutil: Volume root   : 0xf89f
apfsutil: KeyBag        : 0x17d + 0x1
apfsutil: =====================================
apfsutil: Apfs container has 1 volumes
apfsutil: === Parameters of APFS volume 0 ======
apfsutil: Magic [APSB]    : APSB
apfsutil: Object id       : 0x402
apfsutil: Checkpoint id   : 0x5a
apfsutil: Features        : 0x2 ro=0 inc=0x8
apfsutil: Role            : 0
apfsutil: Volume name     : SevenZip
apfsutil: Blocks used     : 0xd77b
apfsutil: LocTree root    : 0xf88e
apfsutil: ExtentTree root : 0xf88b
apfsutil: SnapTree root   : 0x177
apfsutil: Dirs            : 0x24c
apfsutil: Files           : 0x24fe
apfsutil: Symlinks        : 0
apfsutil: Other           : 0
apfsutil: Snapshots       : 0
apfsutil: FileNames       : case sensitive
apfsutil: =====================================
apfsutil: Encrypted volume, ReadOnly Support
apfsutil: Start loading keybag...
apfsutil: Wrong initialization vector value for kek 0x9c3c5e4af3e641ef, should be 0xa6a6a6a6a6a6a6a6
apfsutil: ~CUnixSuperBlock -> 0
apfsutil: ~CUnixFileSystem -> 0