Merge pull request #1466 from paulmillr/patch-2

nip44: clarify ecdh hashing

1 files changed, 2 insertions, 0 deletions

diff --git a/44.md b/44.md
index 78c2323..8f781b8 100644
--- a/44.md
+++ b/44.md
@@ -142,6 +142,8 @@ validation rules, refer to BIP-340.
     The operation produces a shared point, and we encode the shared point's 32-byte x coordinate, using method
     `bytes(P)` from BIP340. Private and public keys must be validated as per BIP340: pubkey must be a valid,
     on-curve point, and private key must be a scalar in range `[1, secp256k1_order - 1]`.
+    NIP44 doesn't do hashing of the output: keep this in mind, because some libraries hash it using sha256.
+    As an example, in libsecp256k1, unhashed version is available in `secp256k1_ec_pubkey_tweak_mul`
 - Operators
   - `x[i:j]`, where `x` is a byte array and `i, j <= 0` returns a `(j - i)`-byte array with a copy of the
     `i`-th byte (inclusive) to the `j`-th byte (exclusive) of `x`.