---
name: "Math::Base85"
section: "3pm"
platform: "linux"
package: "perl-math-base85"
version: "0.5-6"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Math::Base85"
---

# Math::Base85(3pm)

Perl extension for base 85 numbers, as referenced by RFC 1924

## NAME

Math::Base85 - Perl extension for base 85 numbers, as referenced by RFC 1924

## SYNOPSIS

```
  use Math::Base85;
  $bigint = from_base85($number);
  $b85str = to_base85($bigint);
```

## DESCRIPTION

RFC 1924 describes a compact, fixed-size representation of IPv6 addresses which uses a base 85 number system.  This module handles some of the uglier details of it.

The base 85 numbers (from 0 to 84) are as follows:

```
    0..9 A..Z a..z ! # $ % & ( ) * + - ; < = > ? @ ^ _ ` { | } ~
```

At the moment, there's not much in this module.  But it should be sufficient for the purposes of RFC 1924.

This module has a variable called `$Math::Base85::base85_digits`, which is a string containing the digits of the base 85 alphabet from lowest (0) to highest (~), in that order.

Additionally, the following two functions are defined for general use.  (They will be exported upon request.)

## from\_base85

### Parameters

A string composed of valid base 85 digits.

### Returns

A `"Math::BigInt"` object representing the number.

## to\_base85

### Parameters

A `"Math::BigInt"` object.

### Returns

A string of base 85 digits representing the number.

## AUTHORS

- •

  Tony Monroe \<tmonroe+perl@nog.net\>

- •

  Paul Cochrane \<paul@liekut.de\>  (maintainer)

## COPYRIGHT AND LICENSE

Copyright (c) 2001-2002, Tony Monroe \<tmonroe+perl@nog.net\>. All rights reserved. Copyright (c) 2017, Paul Cochrane \<paul@liekut.de\>. All rights reserved.

You may use this software under the same terms as Perl itself.

## SEE ALSO

[**perl**(1)](/perl/1.md).