diff --git a/drivers/auth/crypto_mod.c b/drivers/auth/crypto_mod.c
index c63ff08..127eb0d 100644
--- a/drivers/auth/crypto_mod.c
+++ b/drivers/auth/crypto_mod.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2021, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -114,8 +114,9 @@
  *   data_ptr, data_len: data to be hashed
  *   output: resulting hash
  */
-int crypto_mod_calc_hash(unsigned int alg, void *data_ptr,
-			 unsigned int data_len, unsigned char *output)
+int crypto_mod_calc_hash(enum crypto_md_algo alg, void *data_ptr,
+			 unsigned int data_len,
+			 unsigned char output[CRYPTO_MD_MAX_SIZE])
 {
 	assert(data_ptr != NULL);
 	assert(data_len != 0);
diff --git a/drivers/auth/mbedtls/mbedtls_common.mk b/drivers/auth/mbedtls/mbedtls_common.mk
index 53ebe30..54c819c 100644
--- a/drivers/auth/mbedtls/mbedtls_common.mk
+++ b/drivers/auth/mbedtls/mbedtls_common.mk
@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2015-2020, Arm Limited. All rights reserved.
+# Copyright (c) 2015-2021, Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -96,6 +96,18 @@
     TF_MBEDTLS_USE_AES_GCM	:=	0
 endif
 
+ifeq ($(MEASURED_BOOT),1)
+    ifeq (${TPM_HASH_ALG}, sha256)
+        TF_MBEDTLS_TPM_HASH_ALG_ID	:=	TF_MBEDTLS_SHA256
+    else ifeq (${TPM_HASH_ALG}, sha384)
+        TF_MBEDTLS_TPM_HASH_ALG_ID	:=	TF_MBEDTLS_SHA384
+    else ifeq (${TPM_HASH_ALG}, sha512)
+        TF_MBEDTLS_TPM_HASH_ALG_ID	:=	TF_MBEDTLS_SHA512
+    else
+        $(error "TPM_HASH_ALG not defined.")
+    endif
+endif
+
 # Needs to be set to drive mbed TLS configuration correctly
 $(eval $(call add_defines,\
     $(sort \
@@ -105,6 +117,10 @@
         TF_MBEDTLS_USE_AES_GCM \
 )))
 
+ifeq ($(MEASURED_BOOT),1)
+  $(eval $(call add_define,TF_MBEDTLS_TPM_HASH_ALG_ID))
+endif
+
 $(eval $(call MAKE_LIB,mbedtls))
 
 endif
diff --git a/drivers/auth/mbedtls/mbedtls_crypto.c b/drivers/auth/mbedtls/mbedtls_crypto.c
index 6d6efb5..114e6ad 100644
--- a/drivers/auth/mbedtls/mbedtls_crypto.c
+++ b/drivers/auth/mbedtls/mbedtls_crypto.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2021, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -24,6 +24,16 @@
 
 #define LIB_NAME		"mbed TLS"
 
+#if MEASURED_BOOT
+/*
+ * CRYPTO_MD_MAX_SIZE value is as per current stronger algorithm available
+ * so make sure that mbed TLS MD maximum size must be lesser than this.
+ */
+CASSERT(CRYPTO_MD_MAX_SIZE >= MBEDTLS_MD_MAX_SIZE,
+	assert_mbedtls_md_size_overflow);
+
+#endif /* MEASURED_BOOT */
+
 /*
  * AlgorithmIdentifier  ::=  SEQUENCE  {
  *     algorithm               OBJECT IDENTIFIER,
@@ -211,21 +221,45 @@
 
 #if MEASURED_BOOT
 /*
+ * Map a generic crypto message digest algorithm to the corresponding macro used
+ * by Mbed TLS.
+ */
+static inline mbedtls_md_type_t md_type(enum crypto_md_algo algo)
+{
+	switch (algo) {
+	case CRYPTO_MD_SHA512:
+		return MBEDTLS_MD_SHA512;
+	case CRYPTO_MD_SHA384:
+		return MBEDTLS_MD_SHA384;
+	case CRYPTO_MD_SHA256:
+		return MBEDTLS_MD_SHA256;
+	default:
+		/* Invalid hash algorithm. */
+		return MBEDTLS_MD_NONE;
+	}
+}
+
+/*
  * Calculate a hash
  *
  * output points to the computed hash
  */
-int calc_hash(unsigned int alg, void *data_ptr,
-	      unsigned int data_len, unsigned char *output)
+static int calc_hash(enum crypto_md_algo md_algo, void *data_ptr,
+		     unsigned int data_len,
+		     unsigned char output[CRYPTO_MD_MAX_SIZE])
 {
 	const mbedtls_md_info_t *md_info;
 
-	md_info = mbedtls_md_info_from_type((mbedtls_md_type_t)alg);
+	md_info = mbedtls_md_info_from_type(md_type(md_algo));
 	if (md_info == NULL) {
 		return CRYPTO_ERR_HASH;
 	}
 
-	/* Calculate the hash of the data */
+	/*
+	 * Calculate the hash of the data, it is safe to pass the
+	 * 'output' hash buffer pointer considering its size is always
+	 * bigger than or equal to MBEDTLS_MD_MAX_SIZE.
+	 */
 	return mbedtls_md(md_info, data_ptr, data_len, output);
 }
 #endif /* MEASURED_BOOT */
diff --git a/drivers/measured_boot/event_log/event_log.c b/drivers/measured_boot/event_log/event_log.c
index 52ed278..792f235 100644
--- a/drivers/measured_boot/event_log/event_log.c
+++ b/drivers/measured_boot/event_log/event_log.c
@@ -13,10 +13,19 @@
 #include <common/debug.h>
 #include <drivers/auth/crypto_mod.h>
 #include <drivers/measured_boot/event_log/event_log.h>
-#include <mbedtls/md.h>
 
 #include <plat/common/platform.h>
 
+#if TPM_ALG_ID == TPM_ALG_SHA512
+#define	CRYPTO_MD_ID	CRYPTO_MD_SHA512
+#elif TPM_ALG_ID == TPM_ALG_SHA384
+#define	CRYPTO_MD_ID	CRYPTO_MD_SHA384
+#elif TPM_ALG_ID == TPM_ALG_SHA256
+#define	CRYPTO_MD_ID	CRYPTO_MD_SHA256
+#else
+#  error Invalid TPM algorithm.
+#endif /* TPM_ALG_ID */
+
 /* Running Event Log Pointer */
 static uint8_t *log_ptr;
 
@@ -245,7 +254,7 @@
 int event_log_measure_and_record(uintptr_t data_base, uint32_t data_size,
 				 uint32_t data_id)
 {
-	unsigned char hash_data[MBEDTLS_MD_MAX_SIZE];
+	unsigned char hash_data[CRYPTO_MD_MAX_SIZE];
 	int rc;
 	const event_log_metadata_t *metadata_ptr = plat_metadata_ptr;
 
@@ -257,8 +266,8 @@
 	assert(metadata_ptr->id != EVLOG_INVALID_ID);
 
 	/* Calculate hash */
-	rc = crypto_mod_calc_hash((unsigned int)MBEDTLS_MD_ID,
-				(void *)data_base, data_size, hash_data);
+	rc = crypto_mod_calc_hash(CRYPTO_MD_ID,
+				  (void *)data_base, data_size, hash_data);
 	if (rc != 0) {
 		return rc;
 	}
diff --git a/drivers/measured_boot/event_log/event_log.mk b/drivers/measured_boot/event_log/event_log.mk
index 37e5e29..d3fbbb5 100644
--- a/drivers/measured_boot/event_log/event_log.mk
+++ b/drivers/measured_boot/event_log/event_log.mk
@@ -12,35 +12,24 @@
 TPM_HASH_ALG			:=	sha256
 
 ifeq (${TPM_HASH_ALG}, sha512)
-    MBEDTLS_MD_ID		:=	MBEDTLS_MD_SHA512
     TPM_ALG_ID			:=	TPM_ALG_SHA512
     TCG_DIGEST_SIZE		:=	64U
 else ifeq (${TPM_HASH_ALG}, sha384)
-    MBEDTLS_MD_ID		:=	MBEDTLS_MD_SHA384
     TPM_ALG_ID			:=	TPM_ALG_SHA384
     TCG_DIGEST_SIZE		:=	48U
 else
-    MBEDTLS_MD_ID		:=	MBEDTLS_MD_SHA256
     TPM_ALG_ID			:=	TPM_ALG_SHA256
     TCG_DIGEST_SIZE		:=	32U
-endif
+endif #TPM_HASH_ALG
 
-
-# Set definitions for mbed TLS library and Measured Boot driver
+# Set definitions for Measured Boot driver.
 $(eval $(call add_defines,\
     $(sort \
-        MBEDTLS_MD_ID \
         TPM_ALG_ID \
         TCG_DIGEST_SIZE \
         EVENT_LOG_LEVEL \
 )))
 
-ifeq (${HASH_ALG}, sha256)
-    ifneq (${TPM_HASH_ALG}, sha256)
-        $(eval $(call add_define,MBEDTLS_SHA512_C))
-    endif
-endif
-
 MEASURED_BOOT_SRC_DIR	:= drivers/measured_boot/event_log/
 
 MEASURED_BOOT_SOURCES	:= ${MEASURED_BOOT_SRC_DIR}event_log.c		\