diff --git a/drivers/common/cpt/cpt_ucode.h b/drivers/common/cpt/cpt_ucode.h
index e92e3678c6..4d06625d4c 100644
--- a/drivers/common/cpt/cpt_ucode.h
+++ b/drivers/common/cpt/cpt_ucode.h
@@ -2310,7 +2310,7 @@ cpt_kasumi_dec_prep(uint64_t d_offs,
 	/* consider iv len */
 	encr_offset += iv_len;
 
-	inputlen = iv_len + (RTE_ALIGN(encr_data_len, 8) / 8);
+	inputlen = encr_offset + (RTE_ALIGN(encr_data_len, 8) / 8);
 	outputlen = inputlen;
 
 	/* save space for offset ctrl & iv */