SipHash64 Class
Definition
- Namespace
- Bodu.Security.Cryptography
- Assembly
- Bodu.Security.Cryptography.dll
- Package
- Bodu.Security.Cryptography 1.2.0
- Source
- SipHash.64.cs
Computes a 64-bit keyed hash using the SipHash algorithm by Aumasson and Bernstein. Produces an 8-byte authentication tag from a 128-bit key and is intended to protect hash tables against collision-based denial-of-service attacks. This class cannot be inherited.
public sealed class SipHash64 : SipHash, ICryptoTransform, IDisposable- Inheritance
-
SipHash64
- Implements
- Inherited Members
- Extension Methods
Examples
using Bodu.Security.Cryptography;
// 16-byte secret key - keep it private to your process; SipHash assumes attackers cannot guess it.
byte[] hashTableKey = RandomNumberGenerator.GetBytes(16);
using var sip = new SipHash64 { Key = hashTableKey };
byte[] tag = sip.ComputeHash(System.Text.Encoding.UTF8.GetBytes("user-supplied-key"));Remarks
SipHash64 is parameterized as SipHash-c-d, where c is the number of compression rounds
and d is the number of finalization rounds. The default configuration corresponds to SipHash-2-4;
stronger parameterizations such as SipHash-4-8 may be selected via CompressionRounds
and FinalizationRounds.
See SipHash for a description of the round structure.
Parameters at a glance.
- Tag size: 64 bits (8 bytes).
- Key size: 128 bits (16 bytes).
- Default parameterization: SipHash-2-4 (2 compression rounds, 4 finalization rounds).
- Multi-message key reuse is supported - unlike Poly1305.
When to choose SipHash64. The right keyed hash for protecting in-memory hash tables and bloom filters against collision-based denial-of-service attacks - fast, fixed cost, and the de-facto standard in language runtimes (Python, Ruby, Rust, Perl). For 128-bit tag width or stronger long-term authentication guarantees pick SipHash128; for protocol-level message authentication use HMAC-SHA-256 or Blake2b-MAC.
Constructors
SipHash64()
Initializes a new instance of the SipHash64 class with a fixed 64-bit output size, the default
SipHash-2-4 parameterization, and a freshly generated random key.
public SipHash64()Remarks
The instance is created with the following defaults:
| Property | Default Value |
|---|---|
| CompressionRounds | MinCompressionRounds (2) |
| FinalizationRounds | MinFinalizationRounds (4) |
| HashSize | 64 |
| Key | Cryptographically random 16-byte key containing no zero bytes. |
Applies to
| Product | Versions |
|---|---|
| .NET | 8, 10 |