High Memory Usage using Argon2 Hashing

[OvidM]

Hi, we've been noticing high memory usage in our application with the following parameters for Argon2 Hashing.

MemoryMbSize: 19
Iteration Count: 1
Parallelism: 4
MaxThreads: 6
Salt Length: 32 bytes
Key Length: 32 bytes

When using the same code but with a different library memory is fine, so the code and memory cleanup shouldn't be the problem.

Can I get any help on resolving our memory issues?
Let me know on what I need to provide.

[peterdettman]

The first thing to provide is which library you are referring to, and what version.

e.g. Using current NuGet package:

using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Utilities.Encoders;

var parameters = new Argon2Parameters.Builder()
    .WithIterations(1)
    .WithMemoryAsKB(20000)
    .WithParallelism(4)
    .WithSalt(new byte[32])
    .WithSecret(new byte[32])
    .Build();

var generator = new Argon2BytesGenerator(Task.Factory);
generator.Init(parameters);

byte[] result = new byte[32];
for (int i = 0; i < 10000; ++i)
{
    generator.GenerateBytes("password".ToCharArray(), result);
}

Console.WriteLine(Hex.ToHexString(result));

... the debugger shows memory usage stabilizing below 60MB. If a new generator is instantiated each time, then there is a lot more GC, but the usage still tops out around 150MB.

I assume that you have checked the output is the same to confirm that you are using the same parameters as with the other library (memory sizes can be confusing)?

[OvidM]

Library is Bouncy Castle v2.5.0.

We tested the same code using Konscious with the same parameters and with Libsodium with Salt and Key Length of 16 bytes, and we didn't notice any memory usage issues. I did not verify yet if the output is the same, I assume for Konscious it would be the same but for Libsodium different.

byte[] securePassword = new byte[config.DerivedKeyLength];
var argon = new Argon2BytesGenerator();
var param = new Argon2Parameters.Builder(Argon2Parameters.Argon2id)
                        .WithVersion(Argon2Parameters.Version13)
                        .WithIterations(config.IterationCount)
                        .WithParallelism(config.Argon2DegreeOfParallelism)
                        .WithMemoryAsKB(config.Argon2MemoryMbSize * 1024)
                        .WithSalt(hashSalt).Build();

argon.Init(param);
var data = argon.GenerateBytes(Encoding.UTF8.GetBytes(password), securePassword);


return Convert.ToBase64String(securePassword);