--- /dev/null
+#ifndef _CRYPTO_H
+#define _CRYPTO_H
+
+int encrypt(void *pt, int ptlen, void *key, int keylen, void *ct, int *ctlen);
+int decrypt(void *ct, int ctlen, void *key, int keylen, void *pt, int *ptlen);
+int hash(void *pt, int ptlen, void *tag, int *taglen);
+int hmac(void *pt, int ptlen, void *key, int keylen, void *tag, int *taglen);
+
+#endif