diff --git a/legacy/firmware/crypto.c b/legacy/firmware/crypto.c
index 58c9218da..9c555d7a6 100644
--- a/legacy/firmware/crypto.c
+++ b/legacy/firmware/crypto.c
@@ -110,6 +110,17 @@ int gpgMessageSign(HDNode *node, const uint8_t *message, size_t message_len,
   }
 }
 
+int signifyMessageSign(HDNode *node, const uint8_t *message, size_t message_len,
+                       uint8_t *signature) {
+  signature[0] = 0;  // prefix: pad with zero, so all signatures are 65 bytes
+  const curve_info *ed25519_curve_info = get_curve_by_name(ED25519_NAME);
+  // only ed25519 is supported
+  if (!ed25519_curve_info || node->curve != ed25519_curve_info) {
+    return 1;
+  }
+  return hdnode_sign(node, message, message_len, 0, signature + 1, NULL, NULL);
+}
+
 static void cryptoMessageHash(const CoinInfo *coin, const uint8_t *message,
                               size_t message_len,
                               uint8_t hash[HASHER_DIGEST_LENGTH]) {
diff --git a/legacy/firmware/crypto.h b/legacy/firmware/crypto.h
index fb6352ab1..ff5648bee 100644
--- a/legacy/firmware/crypto.h
+++ b/legacy/firmware/crypto.h
@@ -44,6 +44,9 @@ int sshMessageSign(HDNode *node, const uint8_t *message, size_t message_len,
 int gpgMessageSign(HDNode *node, const uint8_t *message, size_t message_len,
                    uint8_t *signature);
 
+int signifyMessageSign(HDNode *node, const uint8_t *message, size_t message_len,
+                       uint8_t *signature);
+
 int cryptoMessageSign(const CoinInfo *coin, HDNode *node,
                       InputScriptType script_type, const uint8_t *message,
                       size_t message_len, uint8_t *signature);
diff --git a/legacy/firmware/fsm_msg_crypto.h b/legacy/firmware/fsm_msg_crypto.h
index 7864d6bfd..4ce787e36 100644
--- a/legacy/firmware/fsm_msg_crypto.h
+++ b/legacy/firmware/fsm_msg_crypto.h
@@ -118,6 +118,8 @@ void fsm_msgSignIdentity(const SignIdentity *msg) {
       msg->identity.has_proto && (strcmp(msg->identity.proto, "ssh") == 0);
   bool sign_gpg =
       msg->identity.has_proto && (strcmp(msg->identity.proto, "gpg") == 0);
+  bool sign_signify =
+      msg->identity.has_proto && (strcmp(msg->identity.proto, "signify") == 0);
 
   int result = 0;
   layoutProgressSwipe(_("Signing"), 0);
@@ -127,6 +129,10 @@ void fsm_msgSignIdentity(const SignIdentity *msg) {
   } else if (sign_gpg) {  // GPG should sign a message digest
     result = gpgMessageSign(node, msg->challenge_hidden.bytes,
                             msg->challenge_hidden.size, resp->signature.bytes);
+  } else if (sign_signify) {  // Signify should sign a message digest
+    result =
+        signifyMessageSign(node, msg->challenge_hidden.bytes,
+                           msg->challenge_hidden.size, resp->signature.bytes);
   } else {
     uint8_t digest[64];
     sha256_Raw(msg->challenge_hidden.bytes, msg->challenge_hidden.size, digest);
diff --git a/tests/device_tests/test_msg_signidentity.py b/tests/device_tests/test_msg_signidentity.py
index f91294ee3..e9d95c679 100644
--- a/tests/device_tests/test_msg_signidentity.py
+++ b/tests/device_tests/test_msg_signidentity.py
@@ -135,3 +135,37 @@ class TestMsgSignidentity(TrezorTest):
             sig.signature.hex()
             == "00f05e5085e666429de397c70a081932654369619c0bd2a6579ea6c1ef2af112ef79998d6c862a16b932d44b1ac1b83c8cbcd0fbda228274fde9e0d0ca6e9cb709"
         )
+
+        # URI  : gpg://satoshi@bitcoin.org
+        identity = proto.IdentityType(
+            proto="gpg", user="satoshi", host="bitcoin.org", port="", path=""
+        )
+        sig = misc.sign_identity(
+            self.client, identity, hidden, visual, ecdsa_curve_name="ed25519"
+        )
+        assert sig.address is None
+        assert (
+            sig.public_key.hex()
+            == "00d18cdf4dbdbb50ef1fdba1ae0539451f3354a366d6a35313712ab82f16d4cd9e"
+        )
+        assert (
+            sig.signature.hex()
+            == "00f47f1a09a2875b971811ebbece19c3004c3ecbe84e65666dc8c36cc2fc002544af8a3f545375ebe53d73b41c700df2f9020256c31bb774a7eb03ed9819226407"
+        )
+
+        # URI  : signify://satoshi@bitcoin.org
+        identity = proto.IdentityType(
+            proto="signify", user="satoshi", host="bitcoin.org", port="", path=""
+        )
+        sig = misc.sign_identity(
+            self.client, identity, hidden, visual, ecdsa_curve_name="ed25519"
+        )
+        assert sig.address is None
+        assert (
+            sig.public_key.hex()
+            == "0038c0f42c0e47b233e837763098f029fd01009b74fdf4b0d60db114fb0f4f8b17"
+        )
+        assert (
+            sig.signature.hex()
+            == "009bb30a7a894e6cdd86e2b75803745e93bd5294b979f9e00ce9dc870642c7f6ad7322af4c54d401ea793494e8a5fdf2bf8b88c6e875094512bd67b94f9188000d"
+        )