Self identifying base encodings using the Multibase spec
Multibase is a protocol for disambiguating the encoding of base-encoded (e.g., base32, base36, base64, base58, etc.) binary appearing in text.
When text is encoded as bytes, we can usually use a one-size-fits-all encoding (UTF-8) because we're always encoding to the same set of 256 bytes (+/- the NUL byte). When that doesn't work, usually for historical or performance reasons, we can usually infer the encoding from the context.
However, when bytes are encoded as text (using a base encoding), the base choice
of base encoding is often restricted by the context. Worse, these restrictions
can change based on where the data appears in the text. In some cases, we can
[a-z0-9]. In others, we can use a larger set of characters but need a
compact encoding. This has lead to a large set of "base encodings", one for
every use-case. Unlike when encoding text to bytes, we can't just standardize
around a single base encoding because there is no optimal encoding for all
Unfortunately, it's not always clear what base encoding is used; that's where multibase comes in. It answers the question:
Given data d encoded into text s, what base is it encoded with?
Include the following dependency in your Package.swift file
let package = Package( ... dependencies: [ ... .package(url: "https://github.com/swift-libp2p/swift-multibase.git", .upToNextMajor(from: "0.0.1")) ], ... targets: [ .target( ... dependencies: [ ... .product(name: "Multibase", package: "swift-multibase"), ]), ] ... )
import Multibase /// The Multibase format is: /// <base-encoding-character><base-encoded-data> /// Where `<base-encoding-character>` is used according to the multibase table. // To Encode a human readable string into a certain base encoding... "Decentralize Everything!!".encode(as: .base8) // -> "72106254331267164344605543227514510062566312711713506415133463441102" -- Note the '7' multibase prefix tag "Decentralize Everything!!".encode(as: .base64) // -> "mRGVjZW50cmFsaXplIGV2ZXJ5dGhpbmchIQ" -- Note the 'm' multibase prefix tag // To Decode a Multibase encoded string (one that has the proper base prefix prepended)... try BaseEncoding.decodeIntoString("72106254331267164344605543227514510062566312711713506415133463441102") // -> (base: .base8, string: "Decentralize Everything!!") try BaseEncoding.decodeIntoString("mRGVjZW50cmFsaXplIGV2ZXJ5dGhpbmchIQ") // -> (base: .base64, string: "Decentralize Everything!!") /// String/Data/[UInt8] extensions (NOTE: all extensions default to no Multibase prefix!) "Hello World".data(using: .utf8)!.asString(base: .base16) // -> 48656c6c6f20576f726c64 "Hello World".data(using: .utf8)!.asString(base: .base16, withMultibasePrefix: true) // -> f48656c6c6f20576f726c64
/// BaseEncoding Enum let multibase = try! BaseEncoding.decodeIntoString("t8him6pbeehp62r39f9ii0pbmclp7it38d5n6e891") multibase2.base // -> .base32HexPad multibase2.string // -> "Decentralize everything!!" /// String Extensions String(decoding:String, as:BaseEncoding, using:String.Encoding = .utf8) throws String.baseEncoding -> BaseEncoding String.encode(as: BaseEncoding, using:String.Encoding = .ascii) -> String /// Data Extensions Data.init(decoding:String, as:BaseEncoding) throws Data.asString(base:BaseEncoding, withMultibasePrefix:Bool = false) -> String /// Array<UInt8> Extensions Array<UInt8>(decoding:String, as:BaseEncoding) throws Array<UInt8>.asString(base:BaseEncoding, withMultibasePrefix:Bool = false) -> String
Contributions are welcomed! This code is very much a proof of concept. I can guarantee you there's a better / safer way to accomplish the same results. Any suggestions, improvements, or even just critques, are welcome!
Let's make this code better together! 🤝
MIT © 2022 Breth Inc.