diff --git a/docs/user-guide.rst b/docs/user-guide.rst
index 1502c8c..1181495 100644
--- a/docs/user-guide.rst
+++ b/docs/user-guide.rst
@@ -407,8 +407,10 @@
 
 -  ``KEY_ALG``: This build flag enables the user to select the algorithm to be
    used for generating the PKCS keys and subsequent signing of the certificate.
-   It accepts 2 values viz ``rsa``, ``ecdsa``. The default value of this flag
-   is ``rsa``.
+   It accepts 3 values viz ``rsa``, ``rsa_1_5``, ``ecdsa``. The ``rsa_1_5`` is
+   the legacy PKCS#1 RSA 1.5 algorithm which is not TBBR compliant and is
+   retained only for compatibility. The default value of this flag is ``rsa``
+   which is the TBBR compliant PKCS#1 RSA 2.1 scheme.
 
 -  ``LDFLAGS``: Extra user options appended to the linkers' command line in
    addition to the one set by the build system.
diff --git a/drivers/auth/mbedtls/mbedtls_crypto.mk b/drivers/auth/mbedtls/mbedtls_crypto.mk
index 3819716..21b857b 100644
--- a/drivers/auth/mbedtls/mbedtls_crypto.mk
+++ b/drivers/auth/mbedtls/mbedtls_crypto.mk
@@ -9,7 +9,7 @@
 # The platform may define the variable 'TF_MBEDTLS_KEY_ALG' to select the key
 # algorithm to use. If the variable is not defined, select it based on algorithm
 # used for key generation `KEY_ALG`. If `KEY_ALG` is not defined or is
-# defined to `rsa`, then set the variable to `rsa`.
+# defined to `rsa`/`rsa_1_5`, then set the variable to `rsa`.
 ifeq (${TF_MBEDTLS_KEY_ALG},)
     ifeq (${KEY_ALG}, ecdsa)
         TF_MBEDTLS_KEY_ALG		:=	ecdsa
diff --git a/tools/cert_create/include/cert.h b/tools/cert_create/include/cert.h
index 543f122..256e7af 100644
--- a/tools/cert_create/include/cert.h
+++ b/tools/cert_create/include/cert.h
@@ -48,7 +48,7 @@
 int cert_init(void);
 cert_t *cert_get_by_opt(const char *opt);
 int cert_add_ext(X509 *issuer, X509 *subject, int nid, char *value);
-int cert_new(cert_t *cert, int days, int ca, STACK_OF(X509_EXTENSION) * sk);
+int cert_new(int key_alg, cert_t *cert, int days, int ca, STACK_OF(X509_EXTENSION) * sk);
 
 /* Macro to register the certificates used in the CoT */
 #define REGISTER_COT(_certs) \
diff --git a/tools/cert_create/include/key.h b/tools/cert_create/include/key.h
index 4b9e882..304fa61 100644
--- a/tools/cert_create/include/key.h
+++ b/tools/cert_create/include/key.h
@@ -22,7 +22,8 @@
 
 /* Supported key algorithms */
 enum {
-	KEY_ALG_RSA,
+	KEY_ALG_RSA,		/* RSA PSS as defined by PKCS#1 v2.1 (default) */
+	KEY_ALG_RSA_1_5,	/* RSA as defined by PKCS#1 v1.5 */
 #ifndef OPENSSL_NO_EC
 	KEY_ALG_ECDSA,
 #endif /* OPENSSL_NO_EC */
diff --git a/tools/cert_create/src/cert.c b/tools/cert_create/src/cert.c
index 9775664..1b84e36 100644
--- a/tools/cert_create/src/cert.c
+++ b/tools/cert_create/src/cert.c
@@ -79,7 +79,7 @@
 	return 1;
 }
 
-int cert_new(cert_t *cert, int days, int ca, STACK_OF(X509_EXTENSION) * sk)
+int cert_new(int key_alg, cert_t *cert, int days, int ca, STACK_OF(X509_EXTENSION) * sk)
 {
 	EVP_PKEY *pkey = keys[cert->key].key;
 	cert_t *issuer_cert = &certs[cert->issuer];
@@ -90,7 +90,7 @@
 	X509_NAME *name;
 	ASN1_INTEGER *sno;
 	int i, num, rc = 0;
-	EVP_MD_CTX  mdCtx;
+	EVP_MD_CTX mdCtx;
 	EVP_PKEY_CTX *pKeyCtx = NULL;
 
 	/* Create the certificate structure */
@@ -112,24 +112,32 @@
 	}
 
 	EVP_MD_CTX_init(&mdCtx);
+
+	/* Sign the certificate with the issuer key */
 	if (!EVP_DigestSignInit(&mdCtx, &pKeyCtx, EVP_sha256(), NULL, ikey)) {
 		ERR_print_errors_fp(stdout);
 		goto END;
 	}
 
-	if (!EVP_PKEY_CTX_set_rsa_padding(pKeyCtx, RSA_PKCS1_PSS_PADDING)) {
-		ERR_print_errors_fp(stdout);
-		goto END;
-	}
+	/*
+	 * Set additional parameters if algorithm is RSA PSS. This is not
+	 * required for RSA 1.5 or ECDSA.
+	 */
+	if (key_alg == KEY_ALG_RSA) {
+		if (!EVP_PKEY_CTX_set_rsa_padding(pKeyCtx, RSA_PKCS1_PSS_PADDING)) {
+			ERR_print_errors_fp(stdout);
+			goto END;
+		}
 
-	if (!EVP_PKEY_CTX_set_rsa_pss_saltlen(pKeyCtx, RSA_SALT_LEN)) {
-		ERR_print_errors_fp(stdout);
-		goto END;
-	}
+		if (!EVP_PKEY_CTX_set_rsa_pss_saltlen(pKeyCtx, RSA_SALT_LEN)) {
+			ERR_print_errors_fp(stdout);
+			goto END;
+		}
 
-	if (!EVP_PKEY_CTX_set_rsa_mgf1_md(pKeyCtx, EVP_sha256())) {
-		ERR_print_errors_fp(stdout);
-		goto END;
+		if (!EVP_PKEY_CTX_set_rsa_mgf1_md(pKeyCtx, EVP_sha256())) {
+			ERR_print_errors_fp(stdout);
+			goto END;
+		}
 	}
 
 	/* x509.v3 */
diff --git a/tools/cert_create/src/main.c b/tools/cert_create/src/main.c
index f14601c..df59961 100644
--- a/tools/cert_create/src/main.c
+++ b/tools/cert_create/src/main.c
@@ -89,6 +89,7 @@
 
 static const char *key_algs_str[] = {
 	[KEY_ALG_RSA] = "rsa",
+	[KEY_ALG_RSA_1_5] = "rsa_1_5",
 #ifndef OPENSSL_NO_EC
 	[KEY_ALG_ECDSA] = "ecdsa"
 #endif /* OPENSSL_NO_EC */
@@ -223,7 +224,8 @@
 	},
 	{
 		{ "key-alg", required_argument, NULL, 'a' },
-		"Key algorithm: 'rsa' (default), 'ecdsa'"
+		"Key algorithm: 'rsa' (default) - RSAPSS scheme as per \
+PKCS#1 v2.1, 'rsa_1_5' - RSA PKCS#1 v1.5, 'ecdsa'"
 	},
 	{
 		{ "save-keys", no_argument, NULL, 'k' },
@@ -450,8 +452,8 @@
 			sk_X509_EXTENSION_push(sk, cert_ext);
 		}
 
-		/* Create certificate. Signed with ROT key */
-		if (cert->fn && !cert_new(cert, VAL_DAYS, 0, sk)) {
+		/* Create certificate. Signed with corresponding key */
+		if (cert->fn && !cert_new(key_alg, cert, VAL_DAYS, 0, sk)) {
 			ERROR("Cannot create %s\n", cert->cn);
 			exit(1);
 		}