diff --git a/src/lib/tlcl_internal.h b/src/lib/tlcl_internal.h
new file mode 100644
index 0000000..51fe6ef
--- /dev/null
+++ b/src/lib/tlcl_internal.h
@@ -0,0 +1,61 @@
+/* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef TPM_LITE_TLCL_INTERNAL_H_
+#define TPM_LITE_TLCL_INTERNAL_H_
+
+/*
+ * These numbers derive from adding the sizes of command fields as shown in the
+ * TPM commands manual.
+ */
+#define kTpmRequestHeaderLength 10
+#define kTpmResponseHeaderLength 10
+#define kTpmReadInfoLength 12
+#define kEncAuthLength 20
+#define kPcrDigestLength 20
+
+
+/*
+ * Conversion functions.  ToTpmTYPE puts a value of type TYPE into a TPM
+ * command buffer.  FromTpmTYPE gets a value of type TYPE from a TPM command
+ * buffer into a variable.
+ */
+__attribute__((unused))
+static inline void ToTpmUint32(uint8_t *buffer, uint32_t x) {
+  buffer[0] = (uint8_t)(x >> 24);
+  buffer[1] = (uint8_t)((x >> 16) & 0xff);
+  buffer[2] = (uint8_t)((x >> 8) & 0xff);
+  buffer[3] = (uint8_t)(x & 0xff);
+}
+
+/*
+ * See comment for above function.
+ */
+__attribute__((unused))
+static inline void FromTpmUint32(const uint8_t *buffer, uint32_t *x) {
+  *x = ((buffer[0] << 24) |
+        (buffer[1] << 16) |
+        (buffer[2] << 8) |
+        buffer[3]);
+}
+
+/*
+ * See comment for above function.
+ */
+__attribute__((unused))
+static inline void ToTpmUint16(uint8_t *buffer, uint16_t x) {
+  buffer[0] = (uint8_t)(x >> 8);
+  buffer[1] = (uint8_t)(x & 0xff);
+}
+
+/*
+ * See comment for above function.
+ */
+__attribute__((unused))
+static inline void FromTpmUint16(const uint8_t *buffer, uint16_t *x) {
+  *x = (buffer[0] << 8) | buffer[1];
+}
+
+#endif  /* TPM_LITE_TLCL_INTERNAL_H_ */