diff --git a/src/protocols/ssh/ssh_key.c b/src/protocols/ssh/ssh_key.c
index 599985cb..ddaa7f78 100644
--- a/src/protocols/ssh/ssh_key.c
+++ b/src/protocols/ssh/ssh_key.c
@@ -141,13 +141,13 @@ void ssh_key_free(ssh_key* key) {
     free(key);
 }
 
-int ssh_key_sign(ssh_key* key, const char* data, int length, u_char* sig) {
+int ssh_key_sign(ssh_key* key, const char* data, int length, unsigned char* sig) {
 
     const EVP_MD* md;
     EVP_MD_CTX md_ctx;
 
-    u_char digest[EVP_MAX_MD_SIZE];
-    u_int dlen, len;
+    unsigned char digest[EVP_MAX_MD_SIZE];
+    unsigned int dlen, len;
 
     /* Get SHA1 digest */
     if ((md = EVP_get_digestbynid(NID_sha1)) == NULL)
diff --git a/src/protocols/ssh/ssh_key.h b/src/protocols/ssh/ssh_key.h
index 84109f41..0aed7efa 100644
--- a/src/protocols/ssh/ssh_key.h
+++ b/src/protocols/ssh/ssh_key.h
@@ -126,7 +126,7 @@ void ssh_key_free(ssh_key* key);
  * Signs the given data using the given key, returning the length of the
  * signature in bytes, or a value less than zero on error.
  */
-int ssh_key_sign(ssh_key* key, const char* data, int length, u_char* sig);
+int ssh_key_sign(ssh_key* key, const char* data, int length, unsigned char* sig);
 
 #endif