SimpleBase

This is my own take for exotic base encodings like Base32, Base58 and Base85. I started to write it in 2013 as coding practice and kept it as a small pet project. I suggest anyone who wants to brush up their coding skills to give those encoding problems a shot. They turned out to be more challenging than I expected. To grasp the algorithms I had to get a pen and paper to see how the math worked.

Features

• Multibase: All formats covered by SimpleBase including a few Base64 variants are supported. Base2, Base8, and Base10 are also supported.
• Base32: RFC 4648, BECH32, Crockford, z-base-32, Geohash, FileCoin and Extended Hex (BASE32-HEX) flavors with Crockford character substitution, or any other custom flavors.
• Base36: Both lowercase and uppercase alphabets are supported.
• Base45: RFC 9285 is supported.
• Base58: All the standard (Bitcoin (BTC), Ripple (XRP), Monero (XMR)) and custom Base58 encoding methods are supported. Also provides Base58Check and Avalanche (AVAX) CB58 encoding/decoding helpers.
• Base62: The standard Base62 encoding/decoding supported along with a custom alphabet.
• Base85: Ascii85, Z85 and custom flavors. IPv6 encoding/decoding support.
• Base16: UpperCase, LowerCase and ModHex flavors. An experimental hexadecimal encoder/decoder just to see how far I can take the optimizations compared to .NET's implementations. It's quite fast now, but .NET has Convert.FromHexString() method since .NET 5. This is mostly a baseline implementation now (except for when you need ModHex).
• Base256 Emoji🚀: Supported by Multibase, and can also be used individually.
• One-shot memory buffer based APIs for simple use cases.
• Stream-based async APIs for more advanced scenarios.
• Lightweight: No dependencies.
• Support for big-endian CPUs like IBM s390x (zArchitecture).
• Thread-safe.
• Simple to use.

NuGet

To install it from NuGet:

Install-Package SimpleBase

If you need .NET Standard 2.0 compatible version for targeting older .NET Framework or .NET Core, use the 2.x release line instead. It's missing newer features, but still supported:

Install-Package SimpleBase -MaximumVersion 2.999.0

Usage

The basic usage for encoding a buffer into, say, Base32, is as simple as:

using SimpleBase;

byte[] myBuffer;
string result = Base32.Crockford.Encode(myBuffer, padding: true);
// you can also use "ExtendedHex" or "Rfc4648" as encoder flavors

Decoding is also similar:

using SimpleBase;

string myText = ...
byte[] result = Base32.Crockford.Decode(myText);

See the wiki for more types of examples and full documentation.

Benchmark Results

Small buffer sizes are used (64 characters). They are closer to real life applications. Base58 performs really bad in decoding of larger buffer sizes, due to polynomial complexity of numeric base conversions.

BenchmarkDotNet v0.15.8, Windows 11 (10.0.26200.7705/25H2/2025Update/HudsonValley2) AMD Ryzen 9 5950X 4.00GHz, 1 CPU, 32 logical and 16 physical cores .NET SDK 10.0.102 [Host] : .NET 10.0.2 (10.0.2, 10.0.225.61305), X64 RyuJIT x86-64-v3 DefaultJob : .NET 10.0.2 (10.0.2, 10.0.225.61305), X64 RyuJIT x86-64-v3

Method	Mean	Error	StdDev	Gen0	Allocated
DotNet_Base64	22.93 ns	0.413 ns	0.345 ns	0.0120	200 B
Base2_Default	269.93 ns	5.336 ns	5.240 ns	0.0625	1048 B
Base8_Default	133.93 ns	2.183 ns	1.823 ns	0.0219	368 B
Base16_UpperCase	85.39 ns	0.642 ns	0.600 ns	0.0167	280 B
Multibase_Base16_UpperCase	96.92 ns	1.783 ns	3.260 ns	0.0334	560 B
Base32_CrockfordWithPadding	136.41 ns	1.744 ns	1.632 ns	0.0138	232 B
Base36_LowerCase	8,297.76 ns	12.181 ns	10.172 ns	-	224 B
Base45_Default	119.01 ns	2.155 ns	2.725 ns	0.0129	216 B
Base58_Bitcoin	7,333.59 ns	46.523 ns	43.518 ns	0.0076	200 B
Base58_Monero	180.92 ns	1.260 ns	1.117 ns	0.0119	200 B
Base62_Default	7,210.10 ns	11.733 ns	10.975 ns	0.0076	192 B
Base85_Z85	138.75 ns	0.786 ns	0.735 ns	0.0110	184 B
Base256Emoji_Default	215.19 ns	3.288 ns	2.915 ns	0.0162	272 B

Decoding (80 character string, except Base45 which must use an 81 character string)

Method	Mean	Error	StdDev	Gen0	Gen1	Allocated
DotNet_Base64	104.14 ns	1.107 ns	1.035 ns	0.0052	-	88 B
Base2_Default	94.64 ns	0.598 ns	0.559 ns	0.0024	-	40 B
Base8_Default	94.38 ns	1.376 ns	1.149 ns	0.0024	-	40 B
Base16_UpperCase	48.49 ns	0.128 ns	0.107 ns	0.0038	-	64 B
Base16_UpperCase_TextReader	251.52 ns	4.994 ns	10.642 ns	0.4966	0.0155	8312 B
Multibase_Base16_UpperCase	51.67 ns	0.143 ns	0.126 ns	0.0038	-	64 B
Multibase_TryDecode_Base16_UpperCase	45.49 ns	0.090 ns	0.075 ns	-	-	-
Base32_Crockford	96.56 ns	0.793 ns	0.619 ns	0.0048	-	80 B
Base36_LowerCase	3,167.34 ns	22.424 ns	18.725 ns	0.0038	-	80 B
Base45_Default	65.67 ns	0.699 ns	0.654 ns	0.0048	-	80 B
Base58_Bitcoin	3,545.49 ns	11.770 ns	9.829 ns	0.0038	-	88 B
Base58_Monero	75.63 ns	1.222 ns	1.083 ns	0.0052	-	88 B
Base62_Default	3,759.70 ns	63.712 ns	59.596 ns	0.0038	-	88 B
Base85_Z85	237.43 ns	0.770 ns	0.601 ns	0.0052	-	88 B
Base256Emoji_Default	273.74 ns	2.261 ns	1.888 ns	0.0062	-	104 B

Notes

I'm sure there are areas for improvement. I didn't want to go further in optimizations which would hurt readability and extensibility. I might experiment on them in the future.

Test suite for Base32 isn't complete, I took most of it from RFC4648. Base58 really lacks a good spec or test vectors needed. I had to resort to using online converters to generate preliminary test vectors.

Base85 tests are also makseshift tests based on what output Cryptii produces. Contribution to missing test cases are greatly appreciated.

It's interesting that I wasn't able to reach .NET Base64's performance with Base16 with a straightforward managed code despite that it's much simpler. I was only able to match it after I converted Base16 to unsafe code with good independent interleaving so CPU pipeline optimizations could take place. Still not satisfied though. Is .NET's Base64 implementation native? Perhaps.

Thanks

Thanks to all contributors who provided patches, and reported bugs.

Chatting about this pet project with my friends @detaybey, @vhallac, @alkimake and @Utopians at one of our friend's birthday encouraged me to finish this. Thanks guys.