A lightweight generator for short, unique, non-sequential and decodable Hashids from non-negative numbers.

Implementation of the Hashids algorithm.

Hashids are obfuscated unique hashes of non-negative (long) integer numbers, but in contrast to cryptographic one-way hash algorithms they are can be decoded again. The algorithm can be used to either generate a hash from a single number or bundling several numbers into one to be stored as simple short UIDs. This design allows to use them for many use-cases like

• URL shortening
• database ID protection
• shard numbers storage
• invitation-, authorization- and gift codes
• complex- or clustered system parameters

Numbers like 347 are converted into strings like yr8, or an array of numbers like [27, 986] into 3kTMd.

Features

The algorithm provides the following features:

• Generation of short, unique, case-sensitive and non-sequential decodable hashes of natural numbers
• Additional entropy through salt usage
• Configurable minimum hash length and alphabet
• Combining of several numbers to one hash
• Deterministic hash computation given the same input and parametrization/instance configuration
• Prevention of curse words through separator characters

In addition, the library provides features to

• pass 0x or 0X prefixed hexadecimal numbers to the public API methods
• handle exceptions instead of returning empty values when invalid parameters are passed to any public API method
• disable the maximum number size limit which ensures the interoperability with the algorithm reference implementation and allows the usage of the Java Long maximum value

Please note that most features will break the interoperability with the algorithm reference implementation!

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