diff --git a/Makefile.am b/Makefile.am
index f918c97..97a6171 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -17,7 +17,9 @@ if TLS_WITH_GNUTLS
 SSL_CFLAGS = @gnutls_CFLAGS@
 SSL_LIBS = @gnutls_LIBS@
 else
-if !TLS_WITH_SCHANNEL
+if TLS_WITH_SCHANNEL
+SSL_CFLAGS = -DSTROPHE_TLS_SCHANNEL
+else
 SSL_CFLAGS = @openssl_CFLAGS@
 SSL_LIBS = @openssl_LIBS@
 endif
diff --git a/src/scram.c b/src/scram.c
index 35a62db..99f3037 100644
--- a/src/scram.c
+++ b/src/scram.c
@@ -93,12 +93,14 @@ const struct hash_alg scram_sha512_plus = {
  * https://datatracker.ietf.org/doc/html/draft-ietf-kitten-password-storage
  */
 const struct hash_alg *scram_algs[] = {
+#if !defined(STROPHE_TLS_SCHANNEL)
     /* *1 */
     &scram_sha512_plus,
     /* *1 */
     &scram_sha256_plus,
     /* *1 */
     &scram_sha1_plus,
+#endif
     /* *1 */
     &scram_sha512,
     /* *1 */