@@ -481,6 +481,16 @@ include shared.mak
#
# === SHA-1 backend ===
#
+# ==== Security ====
+#
+# Due to the SHAttered (https://shattered.io) attack vector on SHA-1
+# it's strongly recommended to use the sha1collisiondetection
+# counter-cryptanalysis library for SHA-1 hashing (DC_SHA1).
+#
+# If you know that you can trust the repository contents, or where
+# potential SHA-1 attacks are otherwise mitigated the backends listed
+# in "Other SHA-1 implementations" are faster than DC_SHA1.
+#
# ==== Default SHA-1 backend ====
#
# If no *_SHA1 backend is picked we'll fall fall back on using the
@@ -526,6 +536,11 @@ include shared.mak
#
# === SHA-256 backend ===
#
+# ==== Security ====
+#
+# Unlike SHA-1 the SHA-256 algorithm does not suffer from any known
+# vulnerabilities, so any implementation will do.
+#
# ==== Default SHA-256 backend ====
#
# If no *_SHA256 backend is picked we'll fall fall back on using the
Let's mention the SHAttered attack and more generally why we use the sha1collisiondetection backend by default, and note that for SHA-256 the user should feel free to pick any of the supported backends as far as hashing security is concerned. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> --- Makefile | 15 +++++++++++++++ 1 file changed, 15 insertions(+)