bugfix in encryption key computing, added new feature: derived public keys

libpcp/key.h

@@ -113,6 +113,23 @@ unsigned char * pcp_gennonce();
 
 void pcpedit_key(char *keyid);
 
+// proprietary key derivation function. derives an
+// secure encryption key from the given passphrase by
+// calculating a SALSA20 hash from it HCYCLES times.
+// 
+// turns the result into a proper CURVE25519 secret
+// key. allocates memory for key and it is up to the
+// user to free it after use.
+// 
+// deprecation warning: maybe removed once the libsodium
+// developers incorporated some key derivation function
+// into libsodium. so far, there's none but word goes
+// that perhaps something like scrypt() from the star
+// distribution may be added in the future.
+unsigned char *pcp_derivekey(char *passphrase);
+
+pcp_key_t *pcp_derive_pcpkey (pcp_key_t *ours, char *theirs);
+
 #ifdef __cplusplus
 }
 #endif