diff --git a/src/crypt.zig b/src/crypt.zig
index 26bf332..3ef5095 100644
--- a/src/crypt.zig
+++ b/src/crypt.zig
@@ -53,6 +53,7 @@ pub fn encryptWithKey(allocator: std.mem.Allocator, key: [key_size]u8, data: []u
 
     // deal with final block, PKCS#7 padding
     {
+        in = @ptrCast(*[block_size]u8, data[(total_blocks * block_size)..]);
         const padding: u8 = @intCast(u8, block_size - (data.len % block_size));
         var inx: u8 = 0;
         for (data[(total_blocks * block_size)..]) |b| {