diff --git a/inc/CryptX_AuthEnc_OCB.xs.inc b/inc/CryptX_AuthEnc_OCB.xs.inc
index f21a051..e5a92ce 100644
--- a/inc/CryptX_AuthEnc_OCB.xs.inc
+++ b/inc/CryptX_AuthEnc_OCB.xs.inc
@@ -74,8 +74,8 @@
           RETVAL = newSVpvn("", 0);
         }
         else {
-          if (in_data_len % (&self->state)->block_len) {
-            croak ("FATAL: sizeof(data) should be multiple of blocksize (%d)", (&self->state)->block_len);
+          if (in_data_len % 16) {
+            croak ("FATAL: sizeof(data) should be multiple of 16");
           }
           RETVAL = NEWSV(0, in_data_len);
           SvPOK_only(RETVAL);
@@ -135,8 +135,8 @@
           RETVAL = newSVpvn("", 0);
         }
         else {
-          if (in_data_len % (&self->state)->block_len) {
-            croak ("FATAL: sizeof(data) should be multiple of blocksize (%d)", (&self->state)->block_len);
+          if (in_data_len % 16) {
+            croak ("FATAL: sizeof(data) should be multiple of 16");
           }
           RETVAL = NEWSV(0, in_data_len);
           SvPOK_only(RETVAL);
@@ -226,12 +226,3 @@
           }
         }
     }
-
-int
-blocksize(Crypt::AuthEnc::OCB self)
-    CODE:
-    {
-        RETVAL = (&self->state)->block_len;
-    }
-    OUTPUT:
-        RETVAL
diff --git a/lib/Crypt/AuthEnc/OCB.pm b/lib/Crypt/AuthEnc/OCB.pm
index f52cbb0..f35d4b5 100644
--- a/lib/Crypt/AuthEnc/OCB.pm
+++ b/lib/Crypt/AuthEnc/OCB.pm
@@ -53,6 +53,7 @@
 
 # obsolete, only for backwards compatibility
 sub aad_add { goto &adata_add }
+sub blocksize { return 16 }
 
 1;
 
@@ -161,7 +162,7 @@
 
  #BEWARE: size of $ciphertext has to be multiple of blocklen (16 for AES)
 
-=head2 encrypt_last
+=head2 decrypt_last
 
  $plaintext = $ae->decrypt_last($data);