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 (10.0.26200.8894/25H2/2025Update/HudsonValley2) AMD Ryzen 9 5950X 3.40GHz, 1 CPU, 32 logical and 16 physical cores .NET SDK 10.0.302 [Host] : .NET 10.0.10 (10.0.10, 10.0.1026.32716), X64 RyuJIT x86-64-v3 DefaultJob : .NET 10.0.10 (10.0.10, 10.0.1026.32716), X64 RyuJIT x86-64-v3

Method	Mean	Error	StdDev	Gen0	Allocated
DotNet_Base64	17.69 ns	0.117 ns	0.104 ns	0.0120	200 B
Base2_Default	229.76 ns	4.648 ns	8.843 ns	0.0625	1048 B
Base8_Default	110.19 ns	2.138 ns	2.927 ns	0.0219	368 B
Base10_Default	10,380.62 ns	43.676 ns	36.471 ns	0.0153	328 B
Base16_UpperCase	68.47 ns	1.209 ns	1.131 ns	0.0167	280 B
Multibase_Base16_UpperCase	81.15 ns	1.625 ns	3.734 ns	0.0334	560 B
Base32_CrockfordWithPadding	128.36 ns	1.676 ns	1.308 ns	0.0138	232 B
Base36_LowerCase	6,638.64 ns	25.361 ns	23.722 ns	0.0076	224 B
Base45_Default	97.34 ns	1.872 ns	1.659 ns	0.0129	216 B
Base58_Bitcoin	5,849.35 ns	27.707 ns	23.137 ns	0.0076	200 B
Base58_Monero	174.22 ns	3.455 ns	4.613 ns	0.0119	200 B
Base62_Default	5,872.56 ns	98.857 ns	92.471 ns	0.0076	192 B
Base85_Z85	119.07 ns	2.199 ns	2.258 ns	0.0110	184 B
Base256Emoji_Default	160.29 ns	3.073 ns	3.156 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	73.50 ns	0.586 ns	0.548 ns	0.0052	-	88 B
Base2_Default	75.73 ns	0.604 ns	0.535 ns	0.0024	-	40 B
Base8_Default	48.33 ns	0.564 ns	0.441 ns	0.0033	-	56 B
Base10_Default	1,508.23 ns	14.977 ns	14.009 ns	0.0038	-	64 B
Base16_UpperCase	39.44 ns	0.346 ns	0.324 ns	0.0038	-	64 B
Base16_UpperCase_TextReader	208.16 ns	4.168 ns	8.130 ns	0.4966	0.0155	8312 B
Multibase_Base16_UpperCase	41.37 ns	0.832 ns	0.779 ns	0.0038	-	64 B
Multibase_TryDecode_Base16_UpperCase	36.23 ns	0.506 ns	0.395 ns	-	-	-
Base32_Crockford	77.25 ns	0.380 ns	0.355 ns	0.0048	-	80 B
Base36_LowerCase	2,235.53 ns	24.883 ns	23.276 ns	0.0038	-	80 B
Base45_Default	51.74 ns	0.330 ns	0.293 ns	0.0048	-	80 B
Base58_Bitcoin	2,729.74 ns	15.788 ns	13.996 ns	0.0038	-	88 B
Base58_Monero	57.42 ns	0.658 ns	0.513 ns	0.0052	-	88 B
Base62_Default	3,002.94 ns	11.360 ns	9.486 ns	0.0038	-	88 B
Base85_Z85	189.11 ns	1.445 ns	1.352 ns	0.0052	-	88 B
Base256Emoji_Default	223.56 ns	2.182 ns	1.934 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.