Disable DSS by default

.github/workflows/build.yml

@@ -199,8 +199,6 @@ jobs:
       # Sanity check that the binary runs
       - name: genrsa
         run: ~/inst/bin/dropbearkey -t rsa -f testrsa
-      - name: gendss
-        run: ~/inst/bin/dropbearkey -t dss -f testdss
       - name: genecdsa256
         run: ~/inst/bin/dropbearkey -t ecdsa -f testec256 -s 256
       - name: genecdsa384

default_options.h

@@ -127,26 +127,28 @@ IMPORTANT: Some options will require "make clean" after changes */
 
 /* Hostkey/public key algorithms - at least one required, these are used
  * for hostkey as well as for verifying signatures with pubkey auth.
- * Removing either of these won't save very much space.
  * RSA is recommended.
- * DSS may be necessary to connect to some systems though
- * is not recommended for new keys.
+ *
  * See: RSA_PRIV_FILENAME and DSS_PRIV_FILENAME */
 #define DROPBEAR_RSA 1
-/* RSA key generation will be faster with bundled libtommath
+
+/* DSS may be necessary to connect to some systems but is not
+ * recommended for new keys (1024 bits is small, and it uses SHA1).
+ * RSA key generation will be faster with bundled libtommath
  * if DROPBEAR_DSS is disabled.
- * https://github.com/mkj/dropbear/issues/174#issuecomment-1267374858
- */
-#define DROPBEAR_DSS 1
+ * https://github.com/mkj/dropbear/issues/174#issuecomment-1267374858 */
+#define DROPBEAR_DSS 0
 /* ECDSA is significantly faster than RSA or DSS. Compiling in ECC
  * code (either ECDSA or ECDH) increases binary size - around 30kB
  * on x86-64.
  * See: ECDSA_PRIV_FILENAME  */
 #define DROPBEAR_ECDSA 1
+
 /* Ed25519 is faster than ECDSA. Compiling in Ed25519 code increases
  * binary size - around 7,5kB on x86-64.
  * See: ED25519_PRIV_FILENAME  */
 #define DROPBEAR_ED25519 1
+
 /* SK_ECDSA/SK_ED25519 allows u2f security keys for public key auth.
  * This is currently server-only. */
 #define DROPBEAR_SK_ECDSA 1