diff --git a/library/aes.c b/library/aes.c
index 5c939bba4..fce32ce84 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -1142,11 +1142,11 @@ int mbedtls_aes_crypt_xts( mbedtls_aes_xts_context *ctx,
     unsigned char prev_tweak[16];
     unsigned char tmp[16];
 
-    /* Sectors must be at least 16 bytes. */
+    /* Data units must be at least 16 bytes long. */
     if( length < 16 )
         return MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH;
 
-    /* NIST SP 80-38E disallows data units larger than 2**20 blocks. */
+    /* NIST SP 800-38E disallows data units larger than 2**20 blocks. */
     if( length > ( 1 << 20 ) * 16 )
         return MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH;