diff --git a/drivers/auth/auth_mod.c b/drivers/auth/auth_mod.c
index 917ee4a..a99a2c7 100644
--- a/drivers/auth/auth_mod.c
+++ b/drivers/auth/auth_mod.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2021, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2022, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -339,9 +339,6 @@
 	/* Check we have a valid CoT registered */
 	assert(cot_desc_ptr != NULL);
 
-	/* Crypto module */
-	crypto_mod_init();
-
 	/* Image parser module */
 	img_parser_init();
 }
diff --git a/drivers/auth/crypto_mod.c b/drivers/auth/crypto_mod.c
index 127eb0d..eada357 100644
--- a/drivers/auth/crypto_mod.c
+++ b/drivers/auth/crypto_mod.c
@@ -46,8 +46,13 @@
 {
 	assert(crypto_lib_desc.name != NULL);
 	assert(crypto_lib_desc.init != NULL);
+#if TRUSTED_BOARD_BOOT
 	assert(crypto_lib_desc.verify_signature != NULL);
 	assert(crypto_lib_desc.verify_hash != NULL);
+#endif /* TRUSTED_BOARD_BOOT */
+#if MEASURED_BOOT
+	assert(crypto_lib_desc.calc_hash != NULL);
+#endif /* MEASURED_BOOT */
 
 	/* Initialize the cryptographic library */
 	crypto_lib_desc.init();
diff --git a/drivers/auth/mbedtls/mbedtls_crypto.c b/drivers/auth/mbedtls/mbedtls_crypto.c
index 114e6ad..0901d04 100644
--- a/drivers/auth/mbedtls/mbedtls_crypto.c
+++ b/drivers/auth/mbedtls/mbedtls_crypto.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2022, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -60,6 +60,7 @@
 	mbedtls_init();
 }
 
+#if TRUSTED_BOARD_BOOT
 /*
  * Verify a signature.
  *
@@ -218,6 +219,7 @@
 
 	return CRYPTO_SUCCESS;
 }
+#endif /* TRUSTED_BOARD_BOOT */
 
 #if MEASURED_BOOT
 /*
@@ -366,7 +368,7 @@
 /*
  * Register crypto library descriptor
  */
-#if MEASURED_BOOT
+#if MEASURED_BOOT && TRUSTED_BOARD_BOOT
 #if TF_MBEDTLS_USE_AES_GCM
 REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, calc_hash,
 		    auth_decrypt);
@@ -374,11 +376,13 @@
 REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, calc_hash,
 		    NULL);
 #endif
-#else /* MEASURED_BOOT */
+#elif TRUSTED_BOARD_BOOT
 #if TF_MBEDTLS_USE_AES_GCM
 REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash,
 		    auth_decrypt);
 #else
 REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, NULL);
 #endif
-#endif /* MEASURED_BOOT */
+#elif MEASURED_BOOT
+REGISTER_CRYPTO_LIB(LIB_NAME, init, calc_hash);
+#endif /* MEASURED_BOOT && TRUSTED_BOARD_BOOT */