diff --git a/ed25519.c b/ed25519.c
index 1ac3e3d..f200e13 100644
--- a/ed25519.c
+++ b/ed25519.c
@@ -38,17 +38,24 @@
  * The key will have the same format as buf_put_ed25519_key.
  * These should be freed with ed25519_key_free.
  * Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
-int buf_get_ed25519_pub_key(buffer *buf, dropbear_ed25519_key *key, int sk) {
+int buf_get_ed25519_pub_key(buffer *buf, dropbear_ed25519_key *key,
+	enum signkey_type expect_keytype) {
 
-	unsigned int len;
+
+	unsigned int len, typelen;
+	char *keytype = NULL;
+	enum signkey_type buf_keytype;
 
 	TRACE(("enter buf_get_ed25519_pub_key"))
 	dropbear_assert(key != NULL);
 
-	if (sk) {
-		buf_incrpos(buf, 30); /* int + "sk-ssh-ed25519@openssh.com" */
-	} else {
-		buf_incrpos(buf, 4+SSH_SIGNKEY_ED25519_LEN); /* int + "ssh-ed25519" */
+	/* consume and check the key string */
+	keytype = buf_getstring(buf, &typelen);
+	buf_keytype = signkey_type_from_name(keytype, typelen);
+	m_free(keytype);
+	if (buf_keytype != expect_keytype) {
+		TRACE(("leave buf_get_ed25519_pub_key: mismatch key type"))
+		return DROPBEAR_FAILURE;
 	}
 
 	len = buf_getint(buf);
diff --git a/ed25519.h b/ed25519.h
index f415e66..1da9fbd 100644
--- a/ed25519.h
+++ b/ed25519.h
@@ -27,6 +27,7 @@
 
 #include "includes.h"
 #include "buffer.h"
+#include "signkey.h"
 
 #if DROPBEAR_ED25519 
 
@@ -43,7 +44,8 @@ void buf_put_ed25519_sign(buffer* buf, const dropbear_ed25519_key *key, const bu
 #if DROPBEAR_SIGNKEY_VERIFY
 int buf_ed25519_verify(buffer * buf, const dropbear_ed25519_key *key, const buffer *data_buf);
 #endif
-int buf_get_ed25519_pub_key(buffer* buf, dropbear_ed25519_key *key, int sk);
+int buf_get_ed25519_pub_key(buffer *buf, dropbear_ed25519_key *key,
+        enum signkey_type expect_keytype);
 int buf_get_ed25519_priv_key(buffer* buf, dropbear_ed25519_key *key);
 void buf_put_ed25519_pub_key(buffer* buf, const dropbear_ed25519_key *key);
 void buf_put_ed25519_priv_key(buffer* buf, const dropbear_ed25519_key *key);
diff --git a/signkey.c b/signkey.c
index 253154f..8749d85 100644
--- a/signkey.c
+++ b/signkey.c
@@ -232,7 +232,6 @@ int buf_get_pub_key(buffer *buf, sign_key *key, enum signkey_type *type) {
 	unsigned int len;
 	enum signkey_type keytype;
 	int ret = DROPBEAR_FAILURE;
-	int is_sk = 0;
 
 	TRACE2(("enter buf_get_pub_key"))
 
@@ -300,14 +299,9 @@ int buf_get_pub_key(buffer *buf, sign_key *key, enum signkey_type *type) {
 		|| keytype == DROPBEAR_SIGNKEY_SK_ED25519
 #endif
     ) {
-#if DROPBEAR_SK_ED25519
-		if (keytype == DROPBEAR_SIGNKEY_SK_ED25519) {
-			is_sk = 1;
-		}
-#endif
 		ed25519_key_free(key->ed25519key);
 		key->ed25519key = m_malloc(sizeof(*key->ed25519key));
-		ret = buf_get_ed25519_pub_key(buf, key->ed25519key, is_sk);
+		ret = buf_get_ed25519_pub_key(buf, key->ed25519key, keytype);
 		if (ret == DROPBEAR_FAILURE) {
 			m_free(key->ed25519key);
 			key->ed25519key = NULL;
@@ -315,6 +309,19 @@ int buf_get_pub_key(buffer *buf, sign_key *key, enum signkey_type *type) {
 	}
 #endif
 
+#if DROPBEAR_SK_ECDSA || DROPBEAR_SK_ED25519
+	if (0
+#if DROPBEAR_SK_ED25519
+		|| keytype == DROPBEAR_SIGNKEY_SK_ED25519
+#endif
+#if DROPBEAR_SK_ECDSA
+		|| keytype == DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256
+#endif
+	) {
+		key->sk_app = buf_getstring(buf, &key->sk_applen);
+	}
+#endif
+
 	TRACE2(("leave buf_get_pub_key"))
 
 	return ret;
@@ -527,6 +534,7 @@ void sign_key_free(sign_key *key) {
 #endif
 
 	m_free(key->filename);
+	m_free(key->sk_app);
 
 	m_free(key);
 	TRACE2(("leave sign_key_free"))
@@ -672,50 +680,6 @@ void buf_put_sign(buffer* buf, sign_key *key, enum signature_type sigtype,
 
 #if DROPBEAR_SIGNKEY_VERIFY
 
-#if DROPBEAR_SK_ECDSA || DROPBEAR_SK_ED25519
-
-int sk_buf_verify(buffer * buf, sign_key *key, enum signature_type expect_sigtype, const buffer *data_buf, char* app, unsigned int applen) {
-
-	char *type_name = NULL;
-	unsigned int type_name_len = 0;
-	enum signature_type sigtype;
-	enum signkey_type keytype;
-
-	TRACE(("enter sk_buf_verify"))
-
-	buf_getint(buf); /* blob length */
-	type_name = buf_getstring(buf, &type_name_len);
-	sigtype = signature_type_from_name(type_name, type_name_len);
-	m_free(type_name);
-
-	if (expect_sigtype != sigtype) {
-		dropbear_exit("Non-matching signing type");
-	}
-
-	keytype = signkey_type_from_signature(sigtype);
-
-#if DROPBEAR_SK_ECDSA
-	if (keytype == DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256) {
-		ecc_key **eck = (ecc_key**)signkey_key_ptr(key, keytype);
-		if (eck && *eck) {
-			return buf_sk_ecdsa_verify(buf, *eck, data_buf, app, applen);
-		}
-	}
-#endif
-#if DROPBEAR_SK_ED25519
-	if (keytype == DROPBEAR_SIGNKEY_SK_ED25519) {
-		dropbear_ed25519_key **eck = (dropbear_ed25519_key**)signkey_key_ptr(key, keytype);
-		if (eck && *eck) {
-			return buf_sk_ed25519_verify(buf, *eck, data_buf, app, applen);
-		}
-	}
-#endif
-	dropbear_exit("Non-matching signing type");
-	return DROPBEAR_FAILURE;
-}
-
-#endif
-
 /* Return DROPBEAR_SUCCESS or DROPBEAR_FAILURE.
  * If FAILURE is returned, the position of
  * buf is undefined. If SUCCESS is returned, buf will be positioned after the
@@ -729,6 +693,9 @@ int buf_verify(buffer * buf, sign_key *key, enum signature_type expect_sigtype,
 
 	TRACE(("enter buf_verify"))
 
+	printhex("buf", buf->data, buf->pos);
+	printhex("remw", &buf->data[buf->pos], buf->len-buf->pos);
+
 	buf_getint(buf); /* blob length */
 	type_name = buf_getstring(buf, &type_name_len);
 	sigtype = signature_type_from_name(type_name, type_name_len);
@@ -772,6 +739,22 @@ int buf_verify(buffer * buf, sign_key *key, enum signature_type expect_sigtype,
 		return buf_ed25519_verify(buf, key->ed25519key, data_buf);
 	}
 #endif
+#if DROPBEAR_SK_ECDSA
+	if (keytype == DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256) {
+		ecc_key **eck = (ecc_key**)signkey_key_ptr(key, keytype);
+		if (eck && *eck) {
+			return buf_sk_ecdsa_verify(buf, *eck, data_buf, key->sk_app, key->sk_applen);
+		}
+	}
+#endif
+#if DROPBEAR_SK_ED25519
+	if (keytype == DROPBEAR_SIGNKEY_SK_ED25519) {
+		dropbear_ed25519_key **eck = (dropbear_ed25519_key**)signkey_key_ptr(key, keytype);
+		if (eck && *eck) {
+			return buf_sk_ed25519_verify(buf, *eck, data_buf, key->sk_app, key->sk_applen);
+		}
+	}
+#endif
 
 	dropbear_exit("Non-matching signing type");
 	return DROPBEAR_FAILURE;
diff --git a/signkey.h b/signkey.h
index ee0ac11..cc7fd8b 100644
--- a/signkey.h
+++ b/signkey.h
@@ -122,6 +122,12 @@ struct SIGN_key {
 #if DROPBEAR_ED25519
 	struct dropbear_ED25519_Key * ed25519key;
 #endif
+
+#if DROPBEAR_SK_ECDSA || DROPBEAR_SK_ED25519
+	/* application ID for U2F/FIDO key types, a malloced string */
+	char * sk_app;
+	unsigned int sk_applen;
+#endif
 };
 
 typedef struct SIGN_key sign_key;
diff --git a/svr-authpubkey.c b/svr-authpubkey.c
index f325fe8..a33cc39 100644
--- a/svr-authpubkey.c
+++ b/svr-authpubkey.c
@@ -95,12 +95,6 @@ void svr_auth_pubkey(int valid_user) {
 	enum signature_type sigtype;
 	enum signkey_type keytype;
     int auth_failure = 1;
-	int verify_ret = DROPBEAR_FAILURE;
-#if DROPBEAR_SK_ECDSA || DROPBEAR_SK_ED25519
-	char* app = NULL;
-	unsigned int applen;
-	int is_sk = 0;
-#endif
 
 	TRACE(("enter pubkeyauth"))
 
@@ -188,27 +182,11 @@ void svr_auth_pubkey(int valid_user) {
 		goto out;
 	}
 
-#if DROPBEAR_SK_ECDSA || DROPBEAR_SK_ED25519
-#if DROPBEAR_SK_ECDSA
-	if (keytype == DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256) {
-		is_sk = 1;
-	}
-#endif
-#if DROPBEAR_SK_ED25519
-	if (keytype == DROPBEAR_SIGNKEY_SK_ED25519) {
-		is_sk = 1;
-	}
-#endif
-	if (is_sk) {
-		app = buf_getstring (ses.payload, &applen);
-	}
-#endif
-
 	/* create the data which has been signed - this a string containing
 	 * session_id, concatenated with the payload packet up to the signature */
 	assert(ses.payload_beginning <= ses.payload->pos);
 	sign_payload_length = ses.payload->pos - ses.payload_beginning;
-	signbuf = buf_new(ses.payload->pos + 12 + ses.session_id->len);
+	signbuf = buf_new(ses.payload->pos + 4 + ses.session_id->len);
 	buf_putbufstring(signbuf, ses.session_id);
 
 	/* The entire contents of the payload prior. */
@@ -222,16 +200,7 @@ void svr_auth_pubkey(int valid_user) {
 
 	/* ... and finally verify the signature */
 	fp = sign_key_fingerprint(keyblob, keybloblen);
-#if DROPBEAR_SK_ECDSA || DROPBEAR_SK_ED25519
-	if (is_sk) {
-		verify_ret = sk_buf_verify(ses.payload, key, sigtype, signbuf, app, applen);
-	} else {
-		verify_ret = buf_verify(ses.payload, key, sigtype, signbuf);
-	}
-#else
-	verify_ret = buf_verify(ses.payload, key, sigtype, signbuf);
-#endif
-	if (verify_ret == DROPBEAR_SUCCESS) {
+	if (buf_verify(ses.payload, key, sigtype, signbuf) == DROPBEAR_SUCCESS) {
 		dropbear_log(LOG_NOTICE,
 				"Pubkey auth succeeded for '%s' with key %s from %s",
 				ses.authstate.pw_name, fp, svr_ses.addrstring);
@@ -263,11 +232,6 @@ out:
 		sign_key_free(key);
 		key = NULL;
 	}
-#if DROPBEAR_SK_ECDSA || DROPBEAR_SK_ED25519
-	if (app) {
-		m_free(app);
-	}
-#endif
 	/* Retain pubkey options only if auth succeeded */
 	if (!ses.authstate.authdone) {
 		svr_pubkey_options_cleanup();