Mention that we don't change the hash function

Author: real-or-random

bip-schnorr.mediawiki

@@ -21,7 +21,7 @@ This document is licensed under the 2-clause BSD license.
 === Motivation ===
 
 Bitcoin has traditionally used
-[https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm ECDSA] signatures over the [https://www.secg.org/sec2-v2.pdf secp256k1 curve] for authenticating
+[https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm ECDSA] signatures over the [https://www.secg.org/sec2-v2.pdf secp256k1 curve] and with [https://en.wikipedia.org/wiki/SHA-2 SHA256] hashes for authenticating
 transactions. These are [https://www.secg.org/sec1-v2.pdf standardized], but have a number of downsides
 compared to [http://publikationen.ub.uni-frankfurt.de/opus4/files/4280/schnorr.pdf Schnorr signatures] over the same curve:
 
@@ -38,7 +38,7 @@ made:
 * '''Public key encoding''': Instead of using ''compressed'' 33-byte encodings of elliptic curve points which are common in Bitcoin today, public keys in this proposal are encoded as 32 bytes.
 * '''Batch verification''': The specific formulation of ECDSA signatures that is standardized cannot be verified more efficiently in batch compared to individually, unless additional witness data is added. Changing the signature scheme offers an opportunity to address this.
 
-By reusing the same curve as Bitcoin uses for ECDSA, we are able to retain existing mechanisms for choosing secret and public keys, and we avoid introducing new assumptions about elliptic curve group security.
+By reusing the same curve and hash function as Bitcoin has used for ECDSA, we are able to retain existing mechanisms for choosing private and public keys, and we avoid introducing new assumptions about the security of elliptic curves and hash functions.
 
 == Description ==