diff --git a/Makefile.PL b/Makefile.PL
index dbb105b..3f43d36 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -25,6 +25,9 @@ WriteMakefile(
     'MIN_PERL_VERSION' => 5.006,
     'PL_FILES'         => {},
     'LICENSE'          => 'perl',
+    'CONFIGURE_REQUIRES' => {
+        "Crypt::OpenSSL::Guess" => 0.11,
+    },
     'PREREQ_PM' => {
         'Crypt::OpenSSL::Bignum' => 0,
         'Crypt::OpenSSL::Random' => 0,
diff --git a/t/padding.t b/t/padding.t
index 595c30b..3106d1b 100644
--- a/t/padding.t
+++ b/t/padding.t
@@ -48,7 +48,7 @@ sub _Test_Sign_And_Verify {
 
   SKIP: {
         skip "OpenSSL error: illegal or unsupported padding mode - $hash", 6 if $@ =~ /illegal or unsupported padding mode/i;
-        skip "OpenSSL error: invalid digest - $hash", 6 if $@ =~ /invalid digest/i;
+        skip "OpenSSL error: invalid digest - $hash", 6 if $@ =~ /invalid digest|no digest set/i;
         ok(!$@, "Padding method $padding is valid for signing with $hash");
         ok( $rsa_pub->verify( $plaintext, $sig ), "Padding method $padding is valid for verifying with $hash");
 
diff --git a/t/rsa.t b/t/rsa.t
index 5436caf..547c999 100644
--- a/t/rsa.t
+++ b/t/rsa.t
@@ -37,7 +37,7 @@ sub _Test_Sign_And_Verify {
     my $sig = eval { $rsa->sign($plaintext) };
   SKIP: {
         skip "OpenSSL error: illegal or unsupported padding mode - $hash", 5 if $@ =~ /illegal or unsupported padding mode/i;
-        skip "OpenSSL error: invalid digest - $hash", 5 if $@ =~ /invalid digest/i;
+        skip "OpenSSL error: invalid digest - $hash", 5 if $@ =~ /invalid digest|no digest set/i;
         ok( $rsa_pub->verify( $plaintext, $sig ), "rsa_pub verify $hash");
 
         my $false_sig = unpack "H*", $sig;