base69

Base69

Base69 is a binary-to-text encoding scheme inspired by Base64 encoding.

Why Base69 when Base64 is adequate? Because it's NICE!

Technique

Base69 is similar to Base64 - it uses a set of 69 characters (not 64) to represent the data and uses the character = to indicate padding.

Base64 works with blocks of 3 bytes which can be broken into four 6-bit chunks. (6 bits can represent 64 values).

Base69 works with block of 7 bytes instead which can be broken into eight 7-bit chunks. (Need at least 7 bytes to represent 69 values; and since 7 is prime, need at least 7 bytes to break the data into 8 chunks of 7 bits).

The 69 characters in the set are:

ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/-*<>|

Algorithm

• Divide the input byte stream to 7 byte chunks.
• Divide the 56 bits in a chunk to 8 groups of 7 bits.
• Take the numeric value (n) of each 7 bit group and turn them into a 2 character string: Divide n by 69 and get the quotient and remainder. The string's first character is the character corresponding to the remainder and the second character corresponds to the quotient from the 69-character dataset.
• If the trailing data is less than 7 bytes, then extra bytes of value 0 are added at the end to make a 7-byte chunk.
• The last two characters of the encoded padded data are replaced by p= whre p is the number of bytes padded at the end. e.g. if the data at the end is 4 bytes long, 3 bytes are added. So the last 2 characters in the encoded string will be 3=

Implementations

A basic Javascript implementation is added to this project. Implementations in other languages are welcome from contributors.

View demo that turns text to Base69 strings and vice versa.

Javascript API

export declare function encode(bytes: Uint8Array): string;
export declare function decode(value: string): Uint8Array;

FAQ

Why implement Base69?

Because it's noice!

Is it better than Base64?

Not really

License

MIT License (c) Preet Shihn