diff --git a/src/crc128.rs b/src/crc128.rs
index d346e97..5a04156 100644
--- a/src/crc128.rs
+++ b/src/crc128.rs
@@ -78,6 +78,8 @@ const fn update_slice16(
     let len = bytes.len();
     if reflect {
         while i + 16 < len {
+            assert!((i + 15) < len);
+
             let current0 = bytes[i] ^ crc as u8;
             let current1 = bytes[i + 1] ^ (crc >> 8) as u8;
             let current2 = bytes[i + 2] ^ (crc >> 16) as u8;
@@ -122,6 +124,8 @@ const fn update_slice16(
         }
     } else {
         while i + 16 < len {
+            assert!((i + 15) < len);
+
             let current0 = bytes[i] ^ (crc >> 120) as u8;
             let current1 = bytes[i + 1] ^ (crc >> 112) as u8;
             let current2 = bytes[i + 2] ^ (crc >> 104) as u8;
diff --git a/src/crc16.rs b/src/crc16.rs
index b82d949..806765c 100644
--- a/src/crc16.rs
+++ b/src/crc16.rs
@@ -77,6 +77,8 @@ const fn update_slice16(
     let mut i = 0;
     if reflect {
         while i + 16 < len {
+            assert!((i + 15) < len);
+
             let current0 = bytes[i] ^ (crc as u8);
             let current1 = bytes[i + 1] ^ ((crc >> 8) as u8);
 
@@ -107,6 +109,8 @@ const fn update_slice16(
         }
     } else {
         while i + 16 < len {
+            assert!((i + 15) < len);
+
             let current0 = bytes[i] ^ ((crc >> 8) as u8);
             let current1 = bytes[i + 1] ^ (crc as u8);
 
diff --git a/src/crc32.rs b/src/crc32.rs
index 063814f..83269bf 100644
--- a/src/crc32.rs
+++ b/src/crc32.rs
@@ -76,8 +76,11 @@ const fn update_slice16(
     bytes: &[u8],
 ) -> u32 {
     let mut i = 0;
+    let len = bytes.len();
     if reflect {
-        while i + 16 <= bytes.len() {
+        while i + 16 <= len {
+            assert!((i + 15) < len);
+
             let mut current_slice = [bytes[i], bytes[i + 1], bytes[i + 2], bytes[i + 3]];
 
             current_slice[0] ^= crc as u8;
@@ -106,13 +109,15 @@ const fn update_slice16(
         }
 
         // Last few bytes
-        while i < bytes.len() {
+        while i < len{
             let table_index = ((crc ^ bytes[i] as u32) & 0xFF) as usize;
             crc = table[0][table_index] ^ (crc >> 8);
             i += 1;
         }
     } else {
-        while i + 16 <= bytes.len() {
+        while i + 16 <= len {
+            assert!((i + 15) < len);
+
             let mut current_slice = [bytes[i], bytes[i + 1], bytes[i + 2], bytes[i + 3]];
 
             current_slice[0] ^= (crc >> 24) as u8;
@@ -141,7 +146,7 @@ const fn update_slice16(
         }
 
         // Last few bytes
-        while i < bytes.len() {
+        while i < len {
             let table_index = (((crc >> 24) ^ bytes[i] as u32) & 0xFF) as usize;
             crc = table[0][table_index] ^ (crc << 8);
             i += 1;
diff --git a/src/crc64.rs b/src/crc64.rs
index 3fc3233..5380f58 100644
--- a/src/crc64.rs
+++ b/src/crc64.rs
@@ -79,6 +79,8 @@ const fn update_slice16(
     let len = bytes.len();
     if reflect {
         while i + 16 < len {
+            assert!((i + 15) < len);
+
             let current0 = bytes[i] ^ crc as u8;
             let current1 = bytes[i + 1] ^ (crc >> 8) as u8;
             let current2 = bytes[i + 2] ^ (crc >> 16) as u8;
@@ -115,6 +117,8 @@ const fn update_slice16(
         }
     } else {
         while i + 16 < len {
+            assert!((i + 15) < len);
+
             let current0 = bytes[i] ^ (crc >> 56) as u8;
             let current1 = bytes[i + 1] ^ (crc >> 48) as u8;
             let current2 = bytes[i + 2] ^ (crc >> 40) as u8;
diff --git a/src/crc8.rs b/src/crc8.rs
index d075100..804df8b 100644
--- a/src/crc8.rs
+++ b/src/crc8.rs
@@ -58,6 +58,8 @@ const fn update_slice16(mut crc: u8, table: &[[u8; 256]; 16], bytes: &[u8]) -> u
     let mut i = 0;
 
     while i + 16 < len {
+        assert!((i + 15) < len);
+
         crc = table[0][bytes[i + 15] as usize]
             ^ table[1][bytes[i + 14] as usize]
             ^ table[2][bytes[i + 13] as usize]