diff --git a/tools/Makefile b/tools/Makefile
index 766c0674f4a0..afca08e2941a 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -238,6 +238,10 @@ hostprogs-$(CONFIG_MIPS) += mips-relocs
 hostprogs-$(CONFIG_ASN1_COMPILER)	+= asn1_compiler
 HOSTCFLAGS_asn1_compiler.o = -idirafter $(srctree)/include
 
+ifeq ($(CONFIG_TOOLS_LIBCRYPTO),y)
+HOSTLDLIBS_mkeficapsule += \
+	$(shell pkg-config --libs libssl libcrypto 2> /dev/null || echo "-lssl -lcrypto")
+endif
 hostprogs-$(CONFIG_TOOLS_MKEFICAPSULE) += mkeficapsule
 
 # We build some files with extra pedantic flags to try to minimize things
diff --git a/tools/eficapsule.h b/tools/eficapsule.h
new file mode 100644
index 000000000000..8c1560bb0671
--- /dev/null
+++ b/tools/eficapsule.h
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2021 Linaro Limited
+ *		Author: AKASHI Takahiro
+ *
+ * derived from efi.h and efi_api.h to make the file POSIX-compliant
+ */
+
+#ifndef _EFI_CAPSULE_H
+#define _EFI_CAPSULE_H
+
+#include <stdint.h>
+#include <pe.h> /* WIN_CERTIFICATE */
+
+/*
+ * Gcc's predefined attributes are not recognized by clang.
+ */
+#ifndef __packed
+#define __packed	__attribute__((__packed__))
+#endif
+
+#ifndef __aligned
+#define __aligned(x)	__attribute__((__aligned__(x)))
+#endif
+
+typedef struct {
+	uint8_t b[16];
+} efi_guid_t __aligned(8);
+
+#define EFI_GUID(a, b, c, d0, d1, d2, d3, d4, d5, d6, d7) \
+	{{ (a) & 0xff, ((a) >> 8) & 0xff, ((a) >> 16) & 0xff, \
+		((a) >> 24) & 0xff, \
+		(b) & 0xff, ((b) >> 8) & 0xff, \
+		(c) & 0xff, ((c) >> 8) & 0xff, \
+		(d0), (d1), (d2), (d3), (d4), (d5), (d6), (d7) } }
+
+#define EFI_FIRMWARE_MANAGEMENT_CAPSULE_ID_GUID \
+	EFI_GUID(0x6dcbd5ed, 0xe82d, 0x4c44, 0xbd, 0xa1, \
+		 0x71, 0x94, 0x19, 0x9a, 0xd9, 0x2a)
+
+#define EFI_FIRMWARE_IMAGE_TYPE_UBOOT_FIT_GUID \
+	EFI_GUID(0xae13ff2d, 0x9ad4, 0x4e25, 0x9a, 0xc8, \
+		 0x6d, 0x80, 0xb3, 0xb2, 0x21, 0x47)
+
+#define EFI_FIRMWARE_IMAGE_TYPE_UBOOT_RAW_GUID \
+	EFI_GUID(0xe2bb9c06, 0x70e9, 0x4b14, 0x97, 0xa3, \
+		 0x5a, 0x79, 0x13, 0x17, 0x6e, 0x3f)
+
+#define EFI_CERT_TYPE_PKCS7_GUID \
+	EFI_GUID(0x4aafd29d, 0x68df, 0x49ee, 0x8a, 0xa9, \
+		 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7)
+
+/* flags */
+#define CAPSULE_FLAGS_PERSIST_ACROSS_RESET      0x00010000
+
+struct efi_capsule_header {
+	efi_guid_t capsule_guid;
+	uint32_t header_size;
+	uint32_t flags;
+	uint32_t capsule_image_size;
+} __packed;
+
+struct efi_firmware_management_capsule_header {
+	uint32_t version;
+	uint16_t embedded_driver_count;
+	uint16_t payload_item_count;
+	uint32_t item_offset_list[];
+} __packed;
+
+/* image_capsule_support */
+#define CAPSULE_SUPPORT_AUTHENTICATION          0x0000000000000001
+
+struct efi_firmware_management_capsule_image_header {
+	uint32_t version;
+	efi_guid_t update_image_type_id;
+	uint8_t update_image_index;
+	uint8_t reserved[3];
+	uint32_t update_image_size;
+	uint32_t update_vendor_code_size;
+	uint64_t update_hardware_instance;
+	uint64_t image_capsule_support;
+} __packed;
+
+/**
+ * win_certificate_uefi_guid - A certificate that encapsulates
+ * a GUID-specific signature
+ *
+ * @hdr:	Windows certificate header
+ * @cert_type:	Certificate type
+ * @cert_data:	Certificate data
+ */
+struct win_certificate_uefi_guid {
+	WIN_CERTIFICATE	hdr;
+	efi_guid_t cert_type;
+	uint8_t cert_data[];
+} __packed;
+
+/**
+ * efi_firmware_image_authentication - Capsule authentication method
+ * descriptor
+ *
+ * This structure describes an authentication information for
+ * a capsule with IMAGE_ATTRIBUTE_AUTHENTICATION_REQUIRED set
+ * and should be included as part of the capsule.
+ * Only EFI_CERT_TYPE_PKCS7_GUID is accepted.
+ *
+ * @monotonic_count: Count to prevent replay
+ * @auth_info: Authentication info
+ */
+struct efi_firmware_image_authentication {
+	uint64_t monotonic_count;
+	struct win_certificate_uefi_guid auth_info;
+} __packed;
+
+#endif /* _EFI_CAPSULE_H */
diff --git a/tools/mkeficapsule.c b/tools/mkeficapsule.c
index ee3e489c0b30..66dc2ee20912 100644
--- a/tools/mkeficapsule.c
+++ b/tools/mkeficapsule.c
@@ -16,21 +16,17 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
-typedef __u8 u8;
-typedef __u16 u16;
-typedef __u32 u32;
-typedef __u64 u64;
-typedef __s16 s16;
-typedef __s32 s32;
-
-#define aligned_u64 __aligned_u64
-
-#ifndef __packed
-#define __packed __attribute__((packed))
+#include <linux/kconfig.h>
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+#include <openssl/asn1.h>
+#include <openssl/bio.h>
+#include <openssl/evp.h>
+#include <openssl/err.h>
+#include <openssl/pem.h>
+#include <openssl/pkcs7.h>
 #endif
 
-#include <efi.h>
-#include <efi_api.h>
+#include "eficapsule.h"
 
 static const char *tool_name = "mkeficapsule";
 
@@ -39,12 +35,25 @@ efi_guid_t efi_guid_image_type_uboot_fit =
 		EFI_FIRMWARE_IMAGE_TYPE_UBOOT_FIT_GUID;
 efi_guid_t efi_guid_image_type_uboot_raw =
 		EFI_FIRMWARE_IMAGE_TYPE_UBOOT_RAW_GUID;
+efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;
+
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+static const char *opts_short = "f:r:i:I:v:p:c:m:dh";
+#else
+static const char *opts_short = "f:r:i:I:v:h";
+#endif
 
 static struct option options[] = {
 	{"fit", required_argument, NULL, 'f'},
 	{"raw", required_argument, NULL, 'r'},
 	{"index", required_argument, NULL, 'i'},
 	{"instance", required_argument, NULL, 'I'},
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+	{"private-key", required_argument, NULL, 'p'},
+	{"certificate", required_argument, NULL, 'c'},
+	{"monotonic-count", required_argument, NULL, 'm'},
+	{"dump-sig", no_argument, NULL, 'd'},
+#endif
 	{"help", no_argument, NULL, 'h'},
 	{NULL, 0, NULL, 0},
 };
@@ -58,10 +67,253 @@ static void print_usage(void)
 		"\t-r, --raw <raw image>       new raw image file\n"
 		"\t-i, --index <index>         update image index\n"
 		"\t-I, --instance <instance>   update hardware instance\n"
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+		"\t-p, --private-key <privkey file>  private key file\n"
+		"\t-c, --certificate <cert file>     signer's certificate file\n"
+		"\t-m, --monotonic-count <count>     monotonic count\n"
+		"\t-d, --dump_sig              dump signature (*.p7)\n"
+#endif
 		"\t-h, --help                  print a help message\n",
 		tool_name);
 }
 
+/**
+ * auth_context - authentication context
+ * @key_file:	Path to a private key file
+ * @cert_file:	Path to a certificate file
+ * @image_data:	Pointer to firmware data
+ * @image_size:	Size of firmware data
+ * @auth:	Authentication header
+ * @sig_data:	Signature data
+ * @sig_size:	Size of signature data
+ *
+ * Data structure used in create_auth_data(). @key_file through
+ * @image_size are input parameters. @auth, @sig_data and @sig_size
+ * are filled in by create_auth_data().
+ */
+struct auth_context {
+	char *key_file;
+	char *cert_file;
+	uint8_t *image_data;
+	size_t image_size;
+	struct efi_firmware_image_authentication auth;
+	uint8_t *sig_data;
+	size_t sig_size;
+};
+
+static int dump_sig;
+
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+/**
+ * fileio-read_pkey - read out a private key
+ * @filename:	Path to a private key file
+ *
+ * Read out a private key file and parse it into "EVP_PKEY" structure.
+ *
+ * Return:
+ * * Pointer to private key structure  - on success
+ * * NULL - on failure
+ */
+static EVP_PKEY *fileio_read_pkey(const char *filename)
+{
+	EVP_PKEY *key = NULL;
+	BIO *bio;
+
+	bio = BIO_new_file(filename, "r");
+	if (!bio)
+		goto out;
+
+	key = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
+
+out:
+	BIO_free_all(bio);
+	if (!key) {
+		fprintf(stderr, "Can't load key from file '%s'\n", filename);
+		ERR_print_errors_fp(stderr);
+	}
+
+	return key;
+}
+
+/**
+ * fileio-read_cert - read out a certificate
+ * @filename:	Path to a certificate file
+ *
+ * Read out a certificate file and parse it into "X509" structure.
+ *
+ * Return:
+ * * Pointer to certificate structure  - on success
+ * * NULL - on failure
+ */
+static X509 *fileio_read_cert(const char *filename)
+{
+	X509 *cert = NULL;
+	BIO *bio;
+
+	bio = BIO_new_file(filename, "r");
+	if (!bio)
+		goto out;
+
+	cert = PEM_read_bio_X509(bio, NULL, NULL, NULL);
+
+out:
+	BIO_free_all(bio);
+	if (!cert) {
+		fprintf(stderr, "Can't load certificate from file '%s'\n",
+			filename);
+		ERR_print_errors_fp(stderr);
+	}
+
+	return cert;
+}
+
+/**
+ * create_auth_data - compose authentication data in capsule
+ * @auth_context:	Pointer to authentication context
+ *
+ * Fill up an authentication header (.auth) and signature data (.sig_data)
+ * in @auth_context, using library functions from openssl.
+ * All the parameters in @auth_context must be filled in by a caller.
+ *
+ * Return:
+ * * 0  - on success
+ * * -1 - on failure
+ */
+static int create_auth_data(struct auth_context *ctx)
+{
+	EVP_PKEY *key = NULL;
+	X509 *cert = NULL;
+	BIO *data_bio = NULL;
+	const EVP_MD *md;
+	PKCS7 *p7;
+	int flags, ret = -1;
+
+	OpenSSL_add_all_digests();
+	OpenSSL_add_all_ciphers();
+	ERR_load_crypto_strings();
+
+	key = fileio_read_pkey(ctx->key_file);
+	if (!key)
+		goto err;
+	cert = fileio_read_cert(ctx->cert_file);
+	if (!cert)
+		goto err;
+
+	/*
+	 * create a BIO, containing:
+	 *  * firmware image
+	 *  * monotonic count
+	 * in this order!
+	 * See EDK2's FmpAuthenticatedHandlerRsa2048Sha256()
+	 */
+	data_bio = BIO_new(BIO_s_mem());
+	BIO_write(data_bio, ctx->image_data, ctx->image_size);
+	BIO_write(data_bio, &ctx->auth.monotonic_count,
+		  sizeof(ctx->auth.monotonic_count));
+
+	md = EVP_get_digestbyname("SHA256");
+	if (!md)
+		goto err;
+
+	/* create signature */
+	/* TODO: maybe add PKCS7_NOATTR and PKCS7_NOSMIMECAP */
+	flags = PKCS7_BINARY | PKCS7_DETACHED;
+	p7 = PKCS7_sign(NULL, NULL, NULL, data_bio, flags | PKCS7_PARTIAL);
+	if (!p7)
+		goto err;
+	if (!PKCS7_sign_add_signer(p7, cert, key, md, flags))
+		goto err;
+	if (!PKCS7_final(p7, data_bio, flags))
+		goto err;
+
+	/* convert pkcs7 into DER */
+	ctx->sig_data = NULL;
+	ctx->sig_size = ASN1_item_i2d((ASN1_VALUE *)p7, &ctx->sig_data,
+				      ASN1_ITEM_rptr(PKCS7));
+	if (!ctx->sig_size)
+		goto err;
+
+	/* fill auth_info */
+	ctx->auth.auth_info.hdr.dwLength = sizeof(ctx->auth.auth_info)
+						+ ctx->sig_size;
+	ctx->auth.auth_info.hdr.wRevision = WIN_CERT_REVISION_2_0;
+	ctx->auth.auth_info.hdr.wCertificateType = WIN_CERT_TYPE_EFI_GUID;
+	memcpy(&ctx->auth.auth_info.cert_type, &efi_guid_cert_type_pkcs7,
+	       sizeof(efi_guid_cert_type_pkcs7));
+
+	ret = 0;
+err:
+	BIO_free_all(data_bio);
+	EVP_PKEY_free(key);
+	X509_free(cert);
+
+	return ret;
+}
+
+/**
+ * dump_signature - dump out a signature
+ * @path:	Path to a capsule file
+ * @signature:	Signature data
+ * @sig_size:	Size of signature data
+ *
+ * Signature data pointed to by @signature will be saved into
+ * a file whose file name is @path with ".p7" suffix.
+ *
+ * Return:
+ * * 0  - on success
+ * * -1 - on failure
+ */
+static int dump_signature(const char *path, uint8_t *signature, size_t sig_size)
+{
+	char *sig_path;
+	FILE *f;
+	size_t size;
+	int ret = -1;
+
+	sig_path = malloc(strlen(path) + 3 + 1);
+	if (!sig_path)
+		return ret;
+
+	sprintf(sig_path, "%s.p7", path);
+	f = fopen(sig_path, "w");
+	if (!f)
+		goto err;
+
+	size = fwrite(signature, 1, sig_size, f);
+	if (size == sig_size)
+		ret = 0;
+
+	fclose(f);
+err:
+	free(sig_path);
+	return ret;
+}
+
+/**
+ * free_sig_data - free out signature data
+ * @ctx:	Pointer to authentication context
+ *
+ * Free signature data allocated in create_auth_data().
+ */
+static void free_sig_data(struct auth_context *ctx)
+{
+	if (ctx->sig_size)
+		OPENSSL_free(ctx->sig_data);
+}
+#else
+static int create_auth_data(struct auth_context *ctx)
+{
+	return 0;
+}
+
+static int dump_signature(const char *path, uint8_t *signature, size_t sig_size)
+{
+	return 0;
+}
+
+static void free_sig_data(struct auth_context *ctx) {}
+#endif
+
 /**
  * read_bin_file - read a firmware binary file
  * @bin:	Path to a firmware binary file
@@ -168,23 +420,25 @@ static int write_capsule_file(FILE *f, void *data, size_t size, const char *msg)
  * * -1 - on failure
  */
 static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
-			unsigned long index, unsigned long instance)
+			unsigned long index, unsigned long instance,
+			uint64_t mcount, char *privkey_file, char *cert_file)
 {
 	struct efi_capsule_header header;
 	struct efi_firmware_management_capsule_header capsule;
 	struct efi_firmware_management_capsule_image_header image;
+	struct auth_context auth_context;
 	FILE *f;
 	void *data;
 	off_t bin_size;
-	u64 offset;
+	uint64_t offset;
 	int ret;
 
 #ifdef DEBUG
 	fprintf(stderr, "For output: %s\n", path);
 	fprintf(stderr, "\tbin: %s\n\ttype: %pUl\n", bin, guid);
-	fprintf(stderr, "\tindex: %ld\n\tinstance: %ld\n", index, instance);
+	fprintf(stderr, "\tindex: %lu\n\tinstance: %lu\n", index, instance);
 #endif
-
+	auth_context.sig_size = 0;
 	f = NULL;
 	data = NULL;
 	ret = -1;
@@ -195,6 +449,27 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 	if (read_bin_file(bin, &data, &bin_size))
 		goto err;
 
+	/* first, calculate signature to determine its size */
+	if (privkey_file && cert_file) {
+		auth_context.key_file = privkey_file;
+		auth_context.cert_file = cert_file;
+		auth_context.auth.monotonic_count = mcount;
+		auth_context.image_data = data;
+		auth_context.image_size = bin_size;
+
+		if (create_auth_data(&auth_context)) {
+			fprintf(stderr, "Signing firmware image failed\n");
+			goto err;
+		}
+
+		if (dump_sig &&
+		    dump_signature(path, auth_context.sig_data,
+				   auth_context.sig_size)) {
+			fprintf(stderr, "Creating signature file failed\n");
+			goto err;
+		}
+	}
+
 	/*
 	 * write a capsule file
 	 */
@@ -212,9 +487,12 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 	/* TODO: The current implementation ignores flags */
 	header.flags = CAPSULE_FLAGS_PERSIST_ACROSS_RESET;
 	header.capsule_image_size = sizeof(header)
-					+ sizeof(capsule) + sizeof(u64)
+					+ sizeof(capsule) + sizeof(uint64_t)
 					+ sizeof(image)
 					+ bin_size;
+	if (auth_context.sig_size)
+		header.capsule_image_size += sizeof(auth_context.auth)
+				+ auth_context.sig_size;
 	if (write_capsule_file(f, &header, sizeof(header),
 			       "Capsule header"))
 		goto err;
@@ -230,7 +508,7 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 			       "Firmware capsule header"))
 		goto err;
 
-	offset = sizeof(capsule) + sizeof(u64);
+	offset = sizeof(capsule) + sizeof(uint64_t);
 	if (write_capsule_file(f, &offset, sizeof(offset),
 			       "Offset to capsule image"))
 		goto err;
@@ -245,13 +523,32 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 	image.reserved[1] = 0;
 	image.reserved[2] = 0;
 	image.update_image_size = bin_size;
+	if (auth_context.sig_size)
+		image.update_image_size += sizeof(auth_context.auth)
+				+ auth_context.sig_size;
 	image.update_vendor_code_size = 0; /* none */
 	image.update_hardware_instance = instance;
 	image.image_capsule_support = 0;
+	if (auth_context.sig_size)
+		image.image_capsule_support |= CAPSULE_SUPPORT_AUTHENTICATION;
 	if (write_capsule_file(f, &image, sizeof(image),
 			       "Firmware capsule image header"))
 		goto err;
 
+	/*
+	 * signature
+	 */
+	if (auth_context.sig_size) {
+		if (write_capsule_file(f, &auth_context.auth,
+				       sizeof(auth_context.auth),
+				       "Authentication header"))
+			goto err;
+
+		if (write_capsule_file(f, auth_context.sig_data,
+				       auth_context.sig_size, "Signature"))
+			goto err;
+	}
+
 	/*
 	 * firmware binary
 	 */
@@ -262,28 +559,43 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 err:
 	if (f)
 		fclose(f);
+	free_sig_data(&auth_context);
 	free(data);
 
 	return ret;
 }
 
-/*
- * Usage:
- *   $ mkeficapsule -f <firmware binary> <output file>
+/**
+ * main - main entry function of mkeficapsule
+ * @argc:	Number of arguments
+ * @argv:	Array of pointers to arguments
+ *
+ * Create an uefi capsule file, optionally signing it.
+ * Parse all the arguments and pass them on to create_fwbin().
+ *
+ * Return:
+ * * 0  - on success
+ * * -1 - on failure
  */
 int main(int argc, char **argv)
 {
 	char *file;
 	efi_guid_t *guid;
 	unsigned long index, instance;
+	uint64_t mcount;
+	char *privkey_file, *cert_file;
 	int c, idx;
 
 	file = NULL;
 	guid = NULL;
 	index = 0;
 	instance = 0;
+	mcount = 0;
+	privkey_file = NULL;
+	cert_file = NULL;
+	dump_sig = 0;
 	for (;;) {
-		c = getopt_long(argc, argv, "f:r:i:I:v:h", options, &idx);
+		c = getopt_long(argc, argv, opts_short, options, &idx);
 		if (c == -1)
 			break;
 
@@ -291,7 +603,7 @@ int main(int argc, char **argv)
 		case 'f':
 			if (file) {
 				fprintf(stderr, "Image already specified\n");
-				return -1;
+				exit(EXIT_FAILURE);
 			}
 			file = optarg;
 			guid = &efi_guid_image_type_uboot_fit;
@@ -299,7 +611,7 @@ int main(int argc, char **argv)
 		case 'r':
 			if (file) {
 				fprintf(stderr, "Image already specified\n");
-				return -1;
+				exit(EXIT_FAILURE);
 			}
 			file = optarg;
 			guid = &efi_guid_image_type_uboot_raw;
@@ -310,14 +622,40 @@ int main(int argc, char **argv)
 		case 'I':
 			instance = strtoul(optarg, NULL, 0);
 			break;
+#ifdef CONFIG_TOOLS_LIBCRYPTO
+		case 'p':
+			if (privkey_file) {
+				fprintf(stderr,
+					"Private Key already specified\n");
+				exit(EXIT_FAILURE);
+			}
+			privkey_file = optarg;
+			break;
+		case 'c':
+			if (cert_file) {
+				fprintf(stderr,
+					"Certificate file already specified\n");
+				exit(EXIT_FAILURE);
+			}
+			cert_file = optarg;
+			break;
+		case 'm':
+			mcount = strtoul(optarg, NULL, 0);
+			break;
+		case 'd':
+			dump_sig = 1;
+			break;
+#endif /* CONFIG_TOOLS_LIBCRYPTO */
 		case 'h':
 			print_usage();
-			return 0;
+			exit(EXIT_SUCCESS);
 		}
 	}
 
-	/* need an output file */
-	if (argc != optind + 1) {
+	/* check necessary parameters */
+	if ((argc != optind + 1) || !file ||
+	    ((privkey_file && !cert_file) ||
+	     (!privkey_file && cert_file))) {
 		print_usage();
 		exit(EXIT_FAILURE);
 	}
@@ -328,8 +666,8 @@ int main(int argc, char **argv)
 		exit(EXIT_SUCCESS);
 	}
 
-	if (create_fwbin(argv[optind], file, guid, index, instance)
-			< 0) {
+	if (create_fwbin(argv[optind], file, guid, index, instance,
+			 mcount, privkey_file, cert_file) < 0) {
 		fprintf(stderr, "Creating firmware capsule failed\n");
 		exit(EXIT_FAILURE);
 	}
