Encoding format

Weird64 encodes an arbitrary number of bits into six-bit characters.

Default alphabet

0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_

The character at index 0 represents 000000; the character at index 63 represents 111111.

Framing

Given payload bits P:

1. Construct 1 P 1 using leading and trailing sentinel bits.
2. Append the minimum number of 0 bits required to reach a multiple of six.
3. Convert each six-bit group to an alphabet index.

Example:

payload:  101
framed:  1 101 1
padded:  110110
index:       54
output:       s

During decoding, trailing zero padding and the two sentinels are removed. The decoder rejects padding longer than five bits, a missing sentinel, an unknown character, or an invalid alphabet.

Compatibility vectors

Input	Output
Empty bit sequence	m
101	s
101010	rG
00101001010	bAW

Boundaries and security

The trailing sentinel preserves the payload length within one Weird64 value. It does not identify the boundary between concatenated values. Store multiple values in a container format or add an external delimiter.

Weird64 provides no confidentiality, integrity, or authenticity. It must not be used as encryption or as a substitute for a cryptographic construction.