diff --git a/src_features/signMessageEIP712/hash_wrap.c b/src_features/signMessageEIP712/hash_wrap.c
new file mode 100644
index 0000000..be54c26
--- /dev/null
+++ b/src_features/signMessageEIP712/hash_wrap.c
@@ -0,0 +1,33 @@
+#include <stdint.h>
+#include <string.h>
+#include "hash_wrap.h"
+
+cx_sha3_t   global_sha3;
+
+int cx_keccak_init(cx_hash_t *hash, size_t size)
+{
+    sha3_context    *ctx = (sha3_context*)hash;
+
+    (void)size;
+    sha3_Init256(ctx);
+    sha3_SetFlags(ctx, SHA3_FLAGS_KECCAK);
+    return 0;
+}
+
+int cx_hash(cx_hash_t *hash, int mode, const unsigned char *in,
+            unsigned int len, unsigned char *out, unsigned int out_len)
+{
+    sha3_context    *ctx = (sha3_context*)hash;
+    const uint8_t   *result;
+
+    sha3_Update(ctx, in, len);
+    if (mode == CX_LAST)
+    {
+        result = sha3_Finalize(ctx);
+        if (out != NULL)
+        {
+            memmove(out, result, out_len);
+        }
+    }
+    return out_len;
+}
diff --git a/src_features/signMessageEIP712/hash_wrap.h b/src_features/signMessageEIP712/hash_wrap.h
new file mode 100644
index 0000000..5910322
--- /dev/null
+++ b/src_features/signMessageEIP712/hash_wrap.h
@@ -0,0 +1,17 @@
+#ifndef HASH_WRAP_H_
+#define HASH_WRAP_H_
+
+#include <stdlib.h>
+#include "sha3.h"
+
+#define CX_LAST 1
+
+typedef sha3_context cx_sha3_t;
+typedef struct {} cx_hash_t;
+
+extern cx_sha3_t   global_sha3;
+
+int cx_keccak_init(cx_hash_t *hash, size_t size);
+int cx_hash(cx_hash_t *hash, int mode, const unsigned char *in,
+            unsigned int len, unsigned char *out, unsigned int out_len);
+#endif // HASH_WRAP_H_