diff --git a/doc/Building.md b/doc/Building.md
index be3d0f0..d6bb851 100644
--- a/doc/Building.md
+++ b/doc/Building.md
@@ -105,7 +105,7 @@ So far, the following portions of n2n's code benefit from hardware features:
 ```
 AES:               AES-NI
 ChaCha20:          SSE2, SSSE3
-SPECK:             SSE4.2, AVX2, NEON
+SPECK:             SSE2, SSSE3, AVX2, NEON
 Pearson Hashing:   AES-NI
 Random Numbers:    RDSEED, RDRND (not faster but more random seed)
 ```
diff --git a/include/speck.h b/include/speck.h
index 32727e6..04ebd86 100644
--- a/include/speck.h
+++ b/include/speck.h
@@ -46,7 +46,7 @@ typedef struct {
   u64 key[34];
 } speck_context_t;
 
-#elif defined (__SSE4_2__)
+#elif defined (__SSE2__)
 
 #include <immintrin.h>
 #define SPECK_ALIGNED_CTX	16
diff --git a/src/speck.c b/src/speck.c
index 3b78b59..1c8e14b 100644
--- a/src/speck.c
+++ b/src/speck.c
@@ -226,7 +226,7 @@ static int speck_expand_key (const unsigned char *k, speck_context_t *ctx) {
 }
 
 
-#elif defined (__SSE4_2__) // SSE support -------------------------------------------------
+#elif defined (__SSE2__) // SSE support ------------------------------------------------------------
 
 
 #define LCS(x,r) (((x)<<r)|((x)>>(64-r)))
@@ -254,13 +254,19 @@ static int speck_expand_key (const unsigned char *k, speck_context_t *ctx) {
 #define XOR_STORE(in,out,X,Y) (ST(out,XOR(LD(in),LOW(Y,X))), ST(out+16,XOR(LD(in+16),HIGH(Y,X))))
 #define XOR_STORE_ALT(in,out,X,Y) (ST(out,XOR(LD(in),LOW(X,Y))), ST(out+16,XOR(LD(in+16),HIGH(X,Y))))
 
+#define ROL(X,r) (XOR(SL(X,r),SR(X,(64-r))))
+#define ROR(X,r) (XOR(SR(X,r),SL(X,(64-r))))
+
+#if defined (__SSSE3__)  // even SSSE3 -------------------------------
 #define SHFL _mm_shuffle_epi8
 #define R8   _mm_set_epi64x(0x080f0e0d0c0b0a09LL,0x0007060504030201LL)
 #define L8   _mm_set_epi64x(0x0e0d0c0b0a09080fLL,0x0605040302010007LL)
 #define ROL8(X)  (SHFL(X,L8))
 #define ROR8(X)  (SHFL(X,R8))
-#define ROL(X,r) (XOR(SL(X,r),SR(X,(64-r))))
-#define ROR(X,r) (XOR(SR(X,r),SL(X,(64-r))))
+#else // regular SSE2 ------------------------------------------------
+#define ROL8(X)  (ROL(X,8))
+#define ROR8(X)  (ROR(X,8))
+#endif // SSS3 vs. SSE2 ----------------------------------------------
 
 #define numrounds   34
 #define numkeywords 4