diff --git a/src/aes/aesni.rs b/src/aes/aesni.rs
index f41b5d1..d757222 100644
--- a/src/aes/aesni.rs
+++ b/src/aes/aesni.rs
@@ -12,7 +12,7 @@ use std::mem::uninitialized;
 //
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-struct AES128 {
+pub struct AES128 {
     expanded_enc: [__m128i; 11],
     expanded_dec: [__m128i; 11],
 }
diff --git a/src/aes/mod.rs b/src/aes/mod.rs
index 5bb5045..7434fb9 100644
--- a/src/aes/mod.rs
+++ b/src/aes/mod.rs
@@ -1,4 +1,32 @@
 #[cfg(all(any(target_arch="x86", target_arch="x86_64"),
           target_feature = "aes"))]
 pub mod aesni;
-pub mod portable;
\ No newline at end of file
+pub mod portable;
+
+
+#[cfg(all(any(target_arch="x86", target_arch="x86_64"),
+          target_feature = "aes",
+          test))]
+mod flexible {
+    use super::aesni;
+    use super::portable;
+    use super::portable::aes256::{RandomBlock,RandomKey};
+
+    quickcheck! {
+        fn aes128_implementations_match(key: RandomBlock, block: RandomBlock) -> bool {
+            let aesni_key = aesni::AES128::new(&key.block);
+            let portable_key = portable::AES128::new(&key.block);
+            let aesni_cipher = aesni_key.encrypt(&block.block);
+            let portable_cipher = portable_key.encrypt(&block.block);
+            aesni_cipher == portable_cipher
+        }
+
+        fn aes256_implementations_match(key: RandomKey, block: RandomBlock) -> bool {
+            let aesni_key = aesni::AES256::new(&key.key);
+            let portable_key = portable::AES256::new(&key.key);
+            let aesni_cipher = aesni_key.encrypt(&block.block);
+            let portable_cipher = portable_key.encrypt(&block.block);
+            aesni_cipher == portable_cipher
+        }
+    }
+}
diff --git a/src/aes/portable.rs b/src/aes/portable.rs
index 359ef9c..472de94 100644
--- a/src/aes/portable.rs
+++ b/src/aes/portable.rs
@@ -380,7 +380,7 @@ const AES128_BLOCK_SIZE: usize = 4;  // Nb
 const AES128_NUM_ROUNDS: usize = 10; // Nr
 const AES128_STATE_WORDS: usize = AES128_BLOCK_SIZE * (AES128_NUM_ROUNDS + 1);
 
-struct AES128 {
+pub struct AES128 {
     expanded: [u32; AES128_STATE_WORDS]
 }
 
@@ -591,7 +591,7 @@ const AES256_BLOCK_SIZE: usize = 4;  // Nb
 const AES256_NUM_ROUNDS: usize = 14; // Nr
 const AES256_STATE_WORDS: usize = AES256_BLOCK_SIZE * (AES256_NUM_ROUNDS + 1);
 
-struct AES256 {
+pub struct AES256 {
     expanded: [u32; AES256_STATE_WORDS]
 }
 
@@ -694,7 +694,7 @@ impl AES256 {
 }
 
 #[cfg(test)]
-mod aes256 {
+pub(crate) mod aes256 {
     use quickcheck::{Arbitrary,Gen};
     use super::*;
     use testing::run_test;
@@ -781,8 +781,8 @@ mod aes256 {
     }
 
     #[derive(Clone,Debug)]
-    struct RandomKey {
-        key: [u8; 32]
+    pub(crate) struct RandomKey {
+        pub(crate) key: [u8; 32]
     }
 
     impl Arbitrary for RandomKey {
@@ -794,8 +794,8 @@ mod aes256 {
     }
 
     #[derive(Clone,Debug)]
-    pub struct RandomBlock {
-        pub block: [u8; 16]
+    pub(crate) struct RandomBlock {
+        pub(crate) block: [u8; 16]
     }
 
     impl Arbitrary for RandomBlock {