---
name: "File::KDBX::IO::HashBlock"
section: "3pm"
platform: "linux"
package: "libfile-kdbx-perl"
version: "0.906-3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/File::KDBX::IO::HashBlock"
---

# File::KDBX::IO::HashBlock(3pm)

Hash block stream IO handle

## NAME

File::KDBX::IO::HashBlock - Hash block stream IO handle

## VERSION

version 0.906

## DESCRIPTION

Writing to a hash-block handle will transform the data into a series of blocks. Each block is hashed, and the hash is included with the block in the stream.

Reading from a handle, each hash block will be verified as the blocks are disassembled back into a data stream.

This format helps ensure data integrity of KDBX3 files.

Each block is encoded thusly:

- •

  Block index - Little-endian unsigned 32-bit integer, increments starting with 0

- •

  Hash - 32 bytes

- •

  Block size - Little-endian unsigned 32-bit (counting only the data)

- •

  Data - String of bytes

The terminating block is an empty block where hash is 32 null bytes, block size is 0 and there is no data.

## ATTRIBUTES

### algorithm

Digest algorithm in hash-blocking the stream (default: `"SHA-256"`)

### block\_size

Desired block size when writing (default: `$File::KDBX::IO::HashBlock::BLOCK_SIZE` or 1,048,576 bytes)

## METHODS

### new

```
    $fh = File::KDBX::IO::HashBlock->new(%attributes);
    $fh = File::KDBX::IO::HashBlock->new($fh, %attributes);
```

Construct a new hash-block stream IO handle.

## BUGS

Please report any bugs or feature requests on the bugtracker website \<https://github.com/chazmcgarvey/File-KDBX/issues\>

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.

## AUTHOR

Charles McGarvey \<ccm@cpan.org\>

## COPYRIGHT AND LICENSE

This software is copyright (c) 2022 by Charles McGarvey.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.