High-performance BLAKE2 and BLAKE3 cryptographic hash functions for .NET
$ dotnet add package SAIB.Blake2FastThese RFC 7693-compliant BLAKE2 implementations have been tuned for high speed and low memory usage. Span<byte> is used throughout for lower memory overhead compared to byte[] based APIs.
On modern .NET, Blake2Fast includes SIMD-accelerated (SSE2 - AVX-512) implementations of both BLAKE2b and BLAKE2s.
The simplest way to calculate a hash is the one-shot ComputeHash method.
var hash = Blake2b.ComputeHash(data);
BLAKE2 supports variable digest lengths from 1 to 32 bytes for BLAKE2s or 1 to 64 bytes for BLAKE2b.
var hash = Blake2b.ComputeHash(42, data);
BLAKE2 also natively supports keyed hashing.
var hash = Blake2b.ComputeHash(key, data);
BLAKE2 hashes can be incrementally updated if you do not have the data available all at once.
async Task<byte[]> ComputeHashAsync(Stream data)
{
var hasher = Blake2b.CreateIncrementalHasher();
var buffer = ArrayPool<byte>.Shared.Rent(4096);
int bytesRead;
while ((bytesRead = await data.ReadAsync(buffer, 0, buffer.Length)) > 0)
hasher.Update(buffer.AsSpan(0, bytesRead));
ArrayPool<byte>.Shared.Return(buffer);
return hasher.Finish();
}
For convenience, the generic Update<T>() method accepts any value type that does not contain reference fields, plus arrays and Spans of compatible types.
byte[] ComputeCompositeHash()
{
var hasher = Blake2b.CreateIncrementalHasher();
hasher.Update(42);
hasher.Update(Math.Pi);
hasher.Update("I love deadlines. I like the whooshing sound they make as they fly by.".AsSpan());
return hasher.Finish();
}
Be aware that the value passed to Update is added to the hash state in its current memory layout, which may differ based on platform (endianness) or struct layout. Use care when calling Update with types other than byte if the computed hashes are to be used across application or machine boundaries.
For example, if you are adding a string to the hash state, you may hash the characters in memory layout as shown above, or you may use Encoding.GetBytes to ensure the string bytes are handled consistently across platforms.
The output hash digest can be written to an existing buffer to avoid allocating a new array each time.
Span<byte> buffer = stackalloc byte[Blake2b.DefaultDigestLength];
Blake2b.ComputeAndWriteHash(data, buffer);
This is especially useful when performing an iterative hash, as might be used in a key derivation function.
byte[] DeriveBytes(string password, ReadOnlySpan<byte> salt)
{
// Create key from password, then hash the salt using the key
var pwkey = Blake2b.ComputeHash(Encoding.UTF8.GetBytes(password));
var hbuff = Blake2b.ComputeHash(pwkey, salt);
// Hash the hash lots of times, re-using the same buffer
for (int i = 0; i < 999_999; i++)
Blake2b.ComputeAndWriteHash(pwkey, hbuff, hbuff);
return hbuff;
}
For interoperating with code that uses System.Security.Cryptography primitives, Blake2Fast can create a HashAlgorithm wrapper. The wrapper inherits from HMAC in case keyed hashing is required.
HashAlgorithm is less efficient than the above methods, so use it only when necessary for compatibility.
byte[] WriteDataAndCalculateHash(byte[] data, string outFile)
{
using (var hashAlg = Blake2b.CreateHashAlgorithm())
using (var fileStream = new FileStream(outFile, FileMode.Create))
using (var cryptoStream = new CryptoStream(fileStream, hashAlg, CryptoStreamMode.Write))
{
cryptoStream.Write(data, 0, data.Length);
cryptoStream.FlushFinalBlock();
return hashAlg.Hash;
}
}