diff --git a/library/cmac.c b/library/cmac.c
index 04aca7c..0fa5b58 100644
--- a/library/cmac.c
+++ b/library/cmac.c
@@ -105,7 +105,7 @@
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
     }
 
-    for( i = blocksize - 1; i >= 0; i-- )
+    for( i = (int)blocksize - 1; i >= 0; i-- )
     {
         output[i] = input[i] << 1 | overflow;
         overflow = input[i] >> 7;
@@ -209,7 +209,7 @@
     if( ctx == NULL || ctx->cipher_info == NULL || key == NULL )
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
-    if( ( retval = mbedtls_cipher_setkey( ctx, key, keybits,
+    if( ( retval = mbedtls_cipher_setkey( ctx, key, (int)keybits,
                                           MBEDTLS_ENCRYPT ) ) != 0 )
         return( retval );
 
@@ -244,8 +244,8 @@
 {
     mbedtls_cmac_context_t* cmac_ctx;
     unsigned char *state;
-    int n, j, ret = 0;
-    size_t olen, block_size;
+    int ret = 0;
+    size_t n, j, olen, block_size;
 
     if( ctx == NULL || ctx->cipher_info == NULL || input == NULL ||
         ctx->cmac_ctx == NULL )
@@ -280,8 +280,9 @@
     /* n is the number of blocks including any final partial block */
     n = ( ilen + block_size - 1 ) / block_size;
 
-   /* Iterate across the input data in block sized chunks */
-    for( j = 0; j < n - 1; j++ )
+    /* Iterate across the input data in block sized chunks, excluding any
+     * final partial or complete block */
+    for( j = 1; j < n; j++ )
     {
         cmac_xor_block( state, input, state, block_size );