Base256 Encoding in Unicode (base256U)

This repository contains a C++ sample implementation to represent binary data in base256 encoding by using Unicode characters. Typical use cases are representation of: safe passwords, digital keys, checksums, identifiers, hashes, extremely big numbers, or data in character-limited messengers.

What is base256U?

Each byte is represented by exactly one Unicode character (and vice versa). The mapping of byte to Unicode is dead simple:

Byte	Unicode Character	Comment
0-9	‘0’-‘9’	the 10 digits
10-35	‘A’-‘Z’	the 26 uppercase letters
36-61	‘a’-‘z’	the 26 lowercase letters
62-255	‘À’, ‘Á’, ‘Â’, ‘Ã’, ‘Ä’, …	the 194 accent letters

✔️ Advantages

• Ultra compact, e.g. 16 characters like 5iŗ3īÛźUKĺŰÑÞbŒŜ can encode 128-bit of data!
• Easy to recognize due to the accent letters.
• Safe to use: can’t be remembered, so people are forced to copy & paste it (no need to hide it).
• Supports double-clicking for comfortable copy & paste (all Unicode characters are non-terminal ones).
• Supports all Unicode versions: highest code point is 387 which requires Unicode 1.0 only.
• Easy to implement: see base256U.cpp.

🎉 Examples

• 64-bit encoding: ŖÔńĪ07ėñ, or RŧáÃĆĶ2Õ
• 128-bit encoding: ĺËĀ8Ę3ĩŔá0VzœĹŀî, ŽTĭŊõł3ÐÑęGųĢÛąĶ, 5iŗ3īÛźUKĺŰÑÞbŒŜ, or ņĨqvLŀŠsůØŸÙGCŰƀ
• 256-bit encoding: ħŅŹĬšÝŋţĀĸĻňőċqâĮŹúŪßWPŞÓā8æťÁüċ, or Ě2ħŤRŧáÃĆĶ2ÕŀSŜöĄPŞÜbŰ06lŔùö9ĬŒģ

⚖️ Comparison of Encoding Standards

Base	Name	Alphabet	Example	Byte Overhead
2	Binary	0 or 1	0101101	800%
8	Octal	0-7	7734124
10	Decimal	0-9	3849834
16	Hexadecimal	0-9,a-f (case insensitive)	7a9ff34	100%
32	Base32	A-Z,2-7	S7FFQZB	60%
36	Base36	0-9,A-Z	7RT99XQ
45	Base45	0-9,A-Z,space,$,%,*,+,-,.,/,:	8X%/9:A
64	Base64	A-Z,a-z,0-9,+,-	zA8r+8q	33%/37%
85	Base85	!,”,#,…,z	9jqo	25%
256	Base256U	0-9,A-Z,a-z,accent letters	ĘśŃäŞŰÀ	~75%

🔧 Installation

Execute in a terminal window: (C++ compiler and cmake required)

> git clone https://github.com/fleschutz/base256U  # or download & unzip the ZIP file (click the green button)
> cd base256U/src
> cmake .
> make
> ./base256U

The program writes a list of safe passwords (random 128 bits) in base256U encoding. Please use double-clicking and copy & paste.

🎉 Other Use-Cases

• zeichensalat: a tool to make compressed executables for copy & paste using less than 500 unicode characters. It is intended to be used on the fediverse (or in chats).

Safe Password/Key Sizes

Required is a really random password or key to rule out dictionary attacks. Attackers which try every possible key or password (called a ‘brute force attack’) at one billion attempts per second have to wait:

Key Size	Key Example	Max Wait Time @ 1B attempts/sec
40-bit	ŞŰÀ8Œ	about 9 minutes
56-bit	ŖÔńĪ7ėñ	about a year
128-bit	ĤŗwĹĦñŧīijēaqöĜĖŅ	about 5,783,128,169,837,158,197,871 years
256-bit	ÿőMêŽĖiĘśŃäŞŰÀ8ŒŽĎäPfSŖÔńiĪ7ėëŷò	forever

🤝 Contributing

• Contributions, suggestions, and improvements are always welcome!
• Open an Issue if you encounter bugs or have feature ideas.
• Create a Pull Request if you’d like to improve something.

📜 License & Copyright

This open source project is licensed under the CC0 license. All trademarks are the property of their respective owners.