From 779a850e0fb967aac79124c7e18b14706d5f2652 Mon Sep 17 00:00:00 2001
From: Frank Denis
Date: Tue, 25 Feb 2025 15:03:50 +0100
Subject: Add optional support for AEGIS encryption

AEGIS is a new family of authenticated encryption algorithms that offers
stronger security, higher usage limits, and better performance than AES-GCM.

This pull request adds support for a new `-aegis` command-line flag, allowing
AEGIS-128X2 to be used as an alternative to AES-GCM on CPUs with AES acceleration.

It also introduces the ability to use ciphers with different key sizes.

More information on AEGIS is available here:
- https://cfrg.github.io/draft-irtf-cfrg-aegis-aead/draft-irtf-cfrg-aegis-aead.html
- https://github.com/cfrg/draft-irtf-cfrg-aegis-aead

gocryptfs -speed speed on Apple M1:

AES-GCM-256-OpenSSL              3718.79 MB/s
AES-GCM-256-Go                   5083.43 MB/s   (selected in auto mode)
AES-SIV-512-Go                    625.20 MB/s
XChaCha20-Poly1305-OpenSSL       1358.63 MB/s   (selected in auto mode)
XChaCha20-Poly1305-Go             832.11 MB/s
Aegis128X2-Go                   11818.73 MB/s

gocryptfs -speed speed on AMD Zen 4:

AES-GCM-256-OpenSSL              5215.86 MB/s
AES-GCM-256-Go                   6918.01 MB/s   (selected in auto mode)
AES-SIV-512-Go                    449.61 MB/s
XChaCha20-Poly1305-OpenSSL       2643.48 MB/s
XChaCha20-Poly1305-Go            3727.46 MB/s   (selected in auto mode)
Aegis128X2-Go                   28109.92 MB/s
---
 mount.go | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'mount.go')

diff --git a/mount.go b/mount.go
index 0eaa3dd..c9fa639 100644
--- a/mount.go
+++ b/mount.go
@@ -265,6 +265,9 @@ func initFuseFrontend(args *argContainer) (rootNode fs.InodeEmbedder, wipeKeys f
 		}
 		IVBits = chacha20poly1305.NonceSizeX * 8
 	}
+	if args.aegis {
+		cryptoBackend = cryptocore.BackendAegis
+	}
 	// forceOwner implies allow_other, as documented.
 	// Set this early, so args.allow_other can be relied on below this point.
 	if args._forceOwner != nil {
-- 
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