Encode Text to Base91

Base91 Encoder transforms a string so that it conforms to the Base91 Data Encodings specification.

What is Base 91 encode

Base91 is not for encryption purposes and is not secure. It is an encoding mechanism only.

Base 91 is not for encryption purposes and is not secure. It is an encoding mechanism only.

An advanced technique for converting binary data into ASCII letters is base 91. It is comparable to base64 or UUencode but more effective. Base91 generates overhead depending on the input data. It can go as low as 14 percent, which often happens on 0-byte blocks, and reaches a maximum of 23 percent (as opposed to 33 percent for base64). Because of this, base 91 can be highly helpful for sending big data over unreliable binary connections, such as terminal lines or email.
Four of the 95 readable ASCII characters—the space (0x20), apostrophe (0x27), hyphen (0x2d), and backslash—are left out (0x5c).

Base91 Alphabet

'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '!', '#', '$',
'%', '&', '(', ')', '*', '+', ',', '.', '/', ':', ';', '<', '=',
'>', '?', '@', '[', ']', '^', '_', '`', '{', '|', '}', '~', '"'

Executing base91 functions in Rust

let source = "This is a random binary string";

let encode_as_vec: Vec<u8> = base91::slice_encode(source.as_bytes());
let decode_as_vec: Vec<u8> = base91::slice_decode(&encode_as_vec);

Pros and cons of using Base91

Joachim Henke created the base91 binary-to-text encoding technique, often known as base91. The binary data stream is split into 13-bit packets, which are subsequently encoded as two ASCII characters. In general, the size of the encoded data will be 316 times bigger than the original, assuming eight bits per ASCII character. This is more effective than base85's 14 increase and base64's 13 increase (which utilizes four characters to represent three bytes of data) (which uses five characters to represent four bytes of data).

Advantages

• Compared to base85, conversion is quick. Due to the packet's tiny size, a lookup table can be used instead of division or multiplication during encoding and decoding. Base85 would need a 232 lookup table of 5 bytes, which would need at least 5 GiB of RAM if implemented.
• The overhead is only 23% compared to base64, which drops to 14% for 0-byte blocks.
• Because backslash and single quotes are not utilized, many programming languages make it simple to quote.

Disadvantages

• Slower encoding and decoding than base64
• Is challenging to utilize in double-quoted strings without escape characters or raw string because of the use $ and " in the digit alphabet.

Binary Coded Decimal is a type of binary encoding that uses 4 binary numbers to represent the 10 digits from 0 to 9 in a decimal number.