diff --git a/programs/pkey/pk_sign.c b/programs/pkey/pk_sign.c
index 0d02935..ada29f2 100644
--- a/programs/pkey/pk_sign.c
+++ b/programs/pkey/pk_sign.c
@@ -29,6 +29,7 @@
 #if defined(POLARSSL_PLATFORM_C)
 #include "polarssl/platform.h"
 #else
+#define polarssl_snprintf   snprintf
 #define polarssl_printf     printf
 #endif
 
@@ -133,7 +134,7 @@
     /*
      * Write the signature into <filename>-sig.txt
      */
-    snprintf( filename, sizeof(filename), "%s.sig", argv[2] );
+    polarssl_snprintf( filename, sizeof(filename), "%s.sig", argv[2] );
 
     if( ( f = fopen( filename, "wb+" ) ) == NULL )
     {
diff --git a/programs/pkey/pk_verify.c b/programs/pkey/pk_verify.c
index 55f977c..88ad575 100644
--- a/programs/pkey/pk_verify.c
+++ b/programs/pkey/pk_verify.c
@@ -29,6 +29,7 @@
 #if defined(POLARSSL_PLATFORM_C)
 #include "polarssl/platform.h"
 #else
+#define polarssl_snprintf   snprintf
 #define polarssl_printf     printf
 #endif
 
@@ -94,7 +95,7 @@
      * Extract the signature from the text file
      */
     ret = 1;
-    snprintf( filename, sizeof(filename), "%s.sig", argv[2] );
+    polarssl_snprintf( filename, sizeof(filename), "%s.sig", argv[2] );
 
     if( ( f = fopen( filename, "rb" ) ) == NULL )
     {
diff --git a/programs/pkey/rsa_sign_pss.c b/programs/pkey/rsa_sign_pss.c
index de90b7e..45e8482 100644
--- a/programs/pkey/rsa_sign_pss.c
+++ b/programs/pkey/rsa_sign_pss.c
@@ -29,6 +29,7 @@
 #if defined(POLARSSL_PLATFORM_C)
 #include "polarssl/platform.h"
 #else
+#define polarssl_snprintf   snprintf
 #define polarssl_printf     printf
 #endif
 
@@ -143,7 +144,7 @@
     /*
      * Write the signature into <filename>-sig.txt
      */
-    snprintf( filename, 512, "%s.sig", argv[2] );
+    polarssl_snprintf( filename, 512, "%s.sig", argv[2] );
 
     if( ( f = fopen( filename, "wb+" ) ) == NULL )
     {
diff --git a/programs/pkey/rsa_verify_pss.c b/programs/pkey/rsa_verify_pss.c
index dd625b4..5595be5 100644
--- a/programs/pkey/rsa_verify_pss.c
+++ b/programs/pkey/rsa_verify_pss.c
@@ -29,6 +29,7 @@
 #if defined(POLARSSL_PLATFORM_C)
 #include "polarssl/platform.h"
 #else
+#define polarssl_snprintf   snprintf
 #define polarssl_printf     printf
 #endif
 
@@ -105,7 +106,7 @@
      * Extract the RSA signature from the text file
      */
     ret = 1;
-    snprintf( filename, 512, "%s.sig", argv[2] );
+    polarssl_snprintf( filename, 512, "%s.sig", argv[2] );
 
     if( ( f = fopen( filename, "rb" ) ) == NULL )
     {