lib: Add per-message encryption with OpenSSL

This adds a per-message symmetric encryption using the OpenSSL
library. At flow allocation, an Elliptic Curve Diffie-Hellman exchange
is performed to derive a shared secret, which is then hashed using
SHA3-256 to be used as a key for symmetric AES-256 encryption. Each
message on an encrypted flow adds a small crypto header that includes
a random 128-bit Initialization Vector (IV). If the server does not
have OpenSSL enabled, the flow allocation will fail with an -ECRYPT
error.

Future optimizations are to piggyback the public keys on the flow
allocation message, and to enable per-flow encryption that maintains
the context of the encryption over multiple packets and doesn't
require sending IVs.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/lib/qosspec.proto b/src/lib/qosspec.proto
index c9e5a6e6..0cbcd41a 100644
--- a/src/lib/qosspec.proto
+++ b/src/lib/qosspec.proto
@@ -30,4 +30,5 @@ message qosspec_msg {
         required uint32 ber          = 5; /* Bit error rate, ppb */
         required uint32 in_order     = 6; /* In-order delivery */
         required uint32 max_gap      = 7; /* In ms */
+        required uint32 cypher_s     = 8; /* Crypto strength in bits */
 };