README
¶
siphash
Wrapper around github.com/dchest/siphash providing SipHash-2-4 for the go-i2p/crypto ecosystem.
SipHash is used by NTCP2 for obfuscated frame-length encoding.
Functions
| Function | Description |
|---|---|
Hash(k0, k1, data) |
SipHash-2-4 → 64-bit digest |
Hash128(k0, k1, data) |
SipHash-2-4-128 → two 64-bit halves |
New(key) |
Streaming hash.Hash64 for incremental hashing |
New128(key) |
Streaming hash.Hash for 128-bit SipHash |
Documentation
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Overview ¶
Package siphash provides a thin wrapper around github.com/dchest/siphash, centralising third-party SipHash access within the go-i2p/crypto layer.
SipHash is a fast, cryptographically strong pseudorandom function optimised for short inputs. In I2P it is used by NTCP2 for obfuscated frame-length encoding (SipHash-2-4 with a 128-bit key derived during the handshake).
All callers in the go-i2p ecosystem SHOULD import this package instead of the upstream library directly, so that the implementation can be audited and swapped in a single location.
Example usage:
key0, key1 := binary.LittleEndian.Uint64(k[0:8]), binary.LittleEndian.Uint64(k[8:16]) hash := siphash.Hash(key0, key1, data)
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Hash ¶
Hash returns the SipHash-2-4 of the given message with two 64-bit key parts. This is the primary entry-point used by NTCP2 frame-length obfuscation.
Parameters:
- k0: First 64-bit half of the 128-bit SipHash key
- k1: Second 64-bit half of the 128-bit SipHash key
- data: The message to hash
Returns:
- uint64: The 64-bit SipHash-2-4 digest
func Hash128 ¶
Hash128 returns both 64-bit halves of a SipHash-2-4-128 digest. Some protocols require the full 128-bit output for stronger collision resistance or to derive two independent values from a single hash.
Parameters:
- k0: First 64-bit half of the 128-bit SipHash key
- k1: Second 64-bit half of the 128-bit SipHash key
- data: The message to hash
Returns:
- lo: Lower 64 bits of the 128-bit digest
- hi: Upper 64 bits of the 128-bit digest
func New ¶
New returns a new hash.Hash64 computing SipHash-2-4 with the given 128-bit key. The key slice must be exactly 16 bytes long.
The returned hash.Hash64 implements streaming writes via Write() and final digest retrieval via Sum64(), which is useful when data is accumulated incrementally.
Parameters:
- key: A 16-byte (128-bit) SipHash key
Returns:
- hash.Hash64: A streaming SipHash-2-4 instance
Types ¶
This section is empty.
Source Files