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Reworked encryption to use less heap allocated buffers for secrets.

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Also some work on plugin system.
This commit is contained in:
eelke 2026-08-18 07:40:24 +02:00
parent 8782ef39c6
commit 054754f553
42 changed files with 1452 additions and 242 deletions
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39
IdentityShroud.Core/Security/Encryption.cs
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@ -35,36 +35,45 @@ public static class Encryption
return result;
}
public static byte[] Decrypt(ReadOnlyMemory<byte> input, ReadOnlySpan<byte> key)
public static void Decrypt(ReadOnlyMemory<byte> input, ReadOnlySpan<byte> key, Span<byte> output)
{
var payload = input.Span;
int versionNumber = (int)payload[0];
if (versionNumber != 1)
throw new ArgumentException("Invalid payload");
AlgVersion versionParams = _versions[versionNumber];
if (payload.Length < 1 + versionParams.NonceSize + versionParams.TagSize)
throw new ArgumentException("Payload is too short to contain nonce, ciphertext, and tag.", nameof(payload));
AlgVersion versionParams = GetVersionParams(input);
if (input.Length < 1 + versionParams.NonceSize + versionParams.TagSize)
throw new ArgumentException("Cypher data is too short to be valid.", nameof(input));
var payload = input.Span;
ReadOnlySpan<byte> nonce = payload.Slice(1, versionParams.NonceSize);
ReadOnlySpan<byte> tag = payload.Slice(1 + versionParams.NonceSize, versionParams.TagSize);
ReadOnlySpan<byte> cipher = payload.Slice(1 + versionParams.NonceSize + versionParams.TagSize);
byte[] plaintext = new byte[cipher.Length];
using var aes = new AesGcm(key, versionParams.TagSize);
try
{
aes.Decrypt(nonce, cipher, tag, plaintext);
aes.Decrypt(nonce, cipher, tag, output);
}
catch (CryptographicException ex)
{
// Tag verification failed → tampering or wrong key/nonce.
throw new InvalidOperationException("Decryption failed – authentication tag mismatch.", ex);
}
}
return plaintext;
public static int GetDecryptedLength(ReadOnlyMemory<byte> input)
{
AlgVersion versionParams = GetVersionParams(input);
int length = input.Length - (1 + versionParams.NonceSize + versionParams.TagSize);
if (length < 0)
throw new ArgumentException("Cypher data is too short to be valid.", nameof(input));
return length;
}
private static AlgVersion GetVersionParams(ReadOnlyMemory<byte> input)
{
var versionNumber = (int)input.Span[0];
if (versionNumber != 1)
throw new ArgumentException("Invalid payload");
return _versions[versionNumber];
}
}