diff --git a/sw/exts/common/options.mk b/sw/exts/common/options.mk
index 35e13da..2f8be87 100644
--- a/sw/exts/common/options.mk
+++ b/sw/exts/common/options.mk
@@ -21,6 +21,7 @@
 EXT_DIR       := $(SW_DIR)/exts/common
 EXT_SRCS      := $(EXT_DIR)/_crt.c
 EXT_ASMS      :=
+VENDOR_DIR    := $(SW_DIR)/vendor
 
 RV_TOOLS      ?= /tools/riscv/bin/
 OBJCOPY       ?= $(subst gcc,objcopy,$(wordlist 1,1,$(CC)))
@@ -40,6 +41,6 @@
 DEPS           = $(OBJS:%.o=%.d)
 
 LIBS           =-L$(LIB_DIR) -l$(LIB_NAME)
-INCS          +=-I$(LIB_DIR)
+INCS          +=-I$(LIB_DIR) -I$(VENDOR_DIR)
 
 OUTFILES      := $(EXE).elf $(EXE).vmem $(EXE).bin $(EXE).dis $(EXE).map
diff --git a/sw/lib/Makefile b/sw/lib/Makefile
index 922cd58..5220ca0 100644
--- a/sw/lib/Makefile
+++ b/sw/lib/Makefile
@@ -5,18 +5,20 @@
 # Generate a baremetal application for the microcontroller
 
 DIF_SRCS     = uart.c gpio.c spi_device.c flash_ctrl.c hmac.c usbdev.c rv_timer.c
-EXT_SRCS     = usb_controlep.c usb_simpleserial.c irq.c handler.c
+EXT_SRCS     = usb_controlep.c usb_simpleserial.c irq.c handler.c hw_sha256.c
 EXT_ASMS     = irq_vectors.S
 GENHDRS     := ${DIF_SRCS:.c=_regs.h}
 GENHDR_BASE := ${DIF_SRCS:.c=}
 ARCH         = rv32imc
 # ARCH = rv32im # to disable compressed instructions
 
-RV_TOOLS    ?= /tools/riscv/bin/
+RV_TOOLS    ?= /tools/riscv/bin
 
+INCS        += -I../vendor
 CC          := ${RV_TOOLS}/riscv32-unknown-elf-gcc
 CFLAGS      ?= -Wall -g -Os -march=$(ARCH) -mabi=ilp32 -static -mcmodel=medany \
-	       -fvisibility=hidden -nostdlib -nostartfiles
+               -fvisibility=hidden -nostdlib -nostartfiles $(INCS)
+
 
 ifeq ($(SIM),1)
   CFLAGS    += -DSIMULATION
@@ -37,9 +39,6 @@
 
 all: $(OUTFILES)
 
-%.o: %.c %.S
-	$(CC) $(CFLAGS) -MMD -c $(INCS) -o $@ $<
-
 define header_gen
     $1.c: $1_regs.h
 
diff --git a/sw/lib/hw_sha256.c b/sw/lib/hw_sha256.c
new file mode 100644
index 0000000..b6563eb
--- /dev/null
+++ b/sw/lib/hw_sha256.c
@@ -0,0 +1,41 @@
+// Copyright lowRISC contributors.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#include "hw_sha256.h"
+
+#include "hmac.h"
+
+static const HASH_VTAB HW_SHA256_VTAB = {hw_SHA256_init, hw_SHA256_update,
+                                         hw_SHA256_final, hw_SHA256_hash,
+                                         SHA256_DIGEST_SIZE};
+
+static void sha256_init() {
+  hmac_cfg_t config = {.mode = HMAC_OP_SHA256,
+                       .input_endian_swap = 1,
+                       .digest_endian_swap = 1,
+                       .keys = {0}};
+  hmac_init(config);
+}
+
+void hw_SHA256_init(HW_SHA256_CTX *ctx) {
+  // TODO: For security, need to make sure HMAC is not stuck in progress.
+  ctx->f = &HW_SHA256_VTAB;
+  sha256_init();
+}
+
+void hw_SHA256_update(HW_SHA256_CTX *ctx, const void *data, size_t len) {
+  hmac_update(data, len);
+}
+
+const uint8_t *hw_SHA256_final(HW_SHA256_CTX *ctx) {
+  hmac_done((uint32_t *)ctx->buf);
+  return ctx->buf;
+}
+
+const uint8_t *hw_SHA256_hash(const void *data, size_t len, uint8_t *digest) {
+  sha256_init();
+  hmac_update(data, len);
+  hmac_done((uint32_t *)digest);
+  return digest;
+}
diff --git a/sw/lib/hw_sha256.h b/sw/lib/hw_sha256.h
new file mode 100644
index 0000000..178fc49
--- /dev/null
+++ b/sw/lib/hw_sha256.h
@@ -0,0 +1,51 @@
+// Copyright lowRISC contributors.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#ifndef _F_LIB_SHA256_H__
+#define _F_LIB_SHA256_H__
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "cryptoc/hash-internal.h"
+
+typedef HASH_CTX HW_SHA256_CTX;
+
+#define SHA256_DIGEST_SIZE 32
+
+/**
+ * hw_SHA256_init initializes |ctx|.
+ *
+ * @param ctx SHA256 context.
+ */
+void hw_SHA256_init(HW_SHA256_CTX *ctx);
+
+/**
+ * hw_SHA256_update adds |len| bytes from |data| to |ctx|.
+ *
+ * @param ctx SHA256 context.
+ * @param data Input buffer.
+ * @param len Number of bytes to add.
+ */
+void hw_SHA256_update(HW_SHA256_CTX *ctx, const void *data, size_t len);
+
+/**
+ * hw_SHA256_final adds the final padding to |ctx| and calculates digest.
+ *
+ * @param ctx SHA256 context.
+ *
+ * @return pointer to digest buffer held in |ctx|.
+ */
+const uint8_t *hw_SHA256_final(HW_SHA256_CTX *ctx);
+
+/**
+ * hw_SHA256_hash writes |digest| from |len| bytes of |data|.
+ *
+ * @param data Input buffer.
+ * @param len Number of bytes to add.
+ * @param digest Output buffer.
+ */
+const uint8_t *hw_SHA256_hash(const void *data, size_t len, uint8_t *digest);
+
+#endif  // _F_LIB_SHA256_H__
diff --git a/sw/tests/sanity_hmac/Makefile b/sw/tests/hmac/Makefile
similarity index 87%
rename from sw/tests/sanity_hmac/Makefile
rename to sw/tests/hmac/Makefile
index 28da267..61f3e40 100644
--- a/sw/tests/sanity_hmac/Makefile
+++ b/sw/tests/hmac/Makefile
@@ -4,8 +4,8 @@
 #
 # Generate a baremetal application for the microcontroller
 
-NAME         = sanity_hmac
-SRCS         = sanity_hmac.c
+NAME         = sha256_test
+SRCS         = sha256_test.c
 PROGRAM_DIR := $(shell dirname $(realpath $(lastword $(MAKEFILE_LIST))))
 
 include ${PROGRAM_DIR}/../../exts/common/options.mk
diff --git a/sw/tests/sanity_hmac/sanity_hmac.c b/sw/tests/hmac/sha256_test.c
similarity index 61%
rename from sw/tests/sanity_hmac/sanity_hmac.c
rename to sw/tests/hmac/sha256_test.c
index 00cc30f..dd3c23b 100644
--- a/sw/tests/sanity_hmac/sanity_hmac.c
+++ b/sw/tests/hmac/sha256_test.c
@@ -7,18 +7,12 @@
 
 #include "common.h"
 #include "flash_ctrl.h"
-#include "hmac.h"
-#include "hmac_regs.h"
+#include "hw_sha256.h"
 #include "uart.h"
 
-typedef union digest {
-  uint8_t b[32];
-  uint32_t w[8];
-} digest_t;
-
 typedef struct test_data {
   uint32_t digest[8];
-  char sha_input[512];
+  char data[512];
 } test_data_t;
 
 test_data_t test = {
@@ -29,23 +23,16 @@
 
 int main(int argc, char **argv) {
   uint32_t error = 0;
-  digest_t digest;
+  uint32_t digest[8];
 
   uart_init(UART_BAUD_RATE);
-  uart_send_str("SHA256 test.\r\n");
+  uart_send_str("Running SHA256 test\r\n");
 
-  hmac_cfg_t setup = {.mode = HMAC_OP_SHA256,
-                      .input_endian_swap = 1,
-                      .digest_endian_swap = 1,
-                      .keys = {0}};
-
-  hmac_init(setup);
-  hmac_update(test.sha_input, strlen(test.sha_input));
-  hmac_done(digest.w);
+  hw_SHA256_hash(test.data, strlen(test.data), (uint8_t *)digest);
 
   for (uint32_t i = 0; i < 8; i++) {
-    if (digest.w[i] != test.digest[i]) {
-      REG32(FLASH_CTRL_SCRATCH(0)) = digest.w[i];
+    if (digest[i] != test.digest[i]) {
+      REG32(FLASH_CTRL_SCRATCH(0)) = digest[i];
       error++;
       break;
     }