Replaced "Double Ratchet" by "X3DH" in the manual

The Double Ratchet algorithm has other purposes than simple forward
secrecy, and is quite complicated, and rely on some prior key exchange
protocol to boot.  Pointing to it wasn't good general purpose advice.

X3DH is what we were looking for.  It is simple enough, and addresses
the main issues around key exchange (forward secrecy, replay attacks, and
deniability).

diff --git a/doc/man/man3/crypto_key_exchange.3monocypher b/doc/man/man3/crypto_key_exchange.3monocypher
index 734d9d275190fb757e88308f2413940d2c23a424..bbcbfe2ea7d6bb1688dfeb683b024a515148111a 100644 (file)
--- a/doc/man/man3/crypto_key_exchange.3monocypher
+++ b/doc/man/man3/crypto_key_exchange.3monocypher
@@ -95,7 +95,7 @@ uses HChacha20 as well.
 If either of the long term secret keys leaks, it may compromise
 .Em all past messages .
 This can be avoided by using protocols that provide forward secrecy,
-such as the Double Ratchet Algorithm.
+such as the X3DH key agreement protocol.
 .Sh IMPLEMENTATION DETAILS
 .Fn crypto_key_exchange_public_key
 is an alias to

diff --git a/doc/man/man3/crypto_x25519.3monocypher b/doc/man/man3/crypto_x25519.3monocypher
index 48f58fe99b8f067c25494e6144b031409c411c72..e44758cd52dc80b2bb7dc9b6f860480d1a6bdc67 100644 (file)
--- a/doc/man/man3/crypto_x25519.3monocypher
+++ b/doc/man/man3/crypto_x25519.3monocypher
@@ -92,7 +92,7 @@ This function implements X25519, described in RFC 7748.
 If either of the long term secret keys leaks, it may compromise
 .Em all past messages .
 This can be avoided by using protocols that provide forward secrecy,
-such as the Double Ratchet Algorithm.
+such as the X3DH key agreement protocol.
 .Sh IMPLEMENTATION DETAILS
 The most significant bit of the public key is systematically ignored.
 It is not needed because every public key should be smaller than