Add the possibility to load prvate and public keys from an engine and

implement it for nCipher hardware.  The interface in itself should be
clear enough, but the nCipher implementation is currently not the
best when it comes to getting a passphrase from the user.  However,
getting it better is a little hard until a better user interaction
method is create.

Also, use the possibility in req, so we can start to create CSR's with
keys from the nForce box.

WARNING: I've made *no* tests yet, mostly because I didn't implement
this on the machine where I have an nForce box to play with.  All I
know is that it compiles cleanly on Linux...

crypto/engine/engine.h

@@ -64,6 +64,7 @@
 #include <openssl/dsa.h>
 #include <openssl/dh.h>
 #include <openssl/rand.h>
+#include <openssl/evp.h>
 
 #ifdef  __cplusplus
 extern "C" {
@@ -85,7 +86,8 @@ extern "C" {
  * All command numbers are shared between all engines, even if some don't
  * make sense to some engines.  In such a case, they do nothing but return
  * the error ENGINE_R_CTRL_COMMAND_NOT_IMPLEMENTED. */
-#define ENGINE_CTRL_SET_LOGSTREAM	1
+#define ENGINE_CTRL_SET_LOGSTREAM		1
+#define ENGINE_CTRL_SET_PASSWORD_CALLBACK	2
 
 
 /* As we're missing a BIGNUM_METHOD, we need a couple of locally
@@ -229,6 +231,14 @@ int ENGINE_finish(ENGINE *e);
 /* WARNING: This is currently experimental and may change radically! */
 int ENGINE_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)());
 
+/* The following functions handle keys that are stored in some secondary
+ * location, handled by the engine.  The storage may be on a card or
+ * whatever. */
+EVP_PKEY *ENGINE_load_private_key(ENGINE *e, const char *key_id,
+	const char *passphrase);
+EVP_PKEY *ENGINE_load_public_key(ENGINE *e, const char *key_id,
+	const char *passphrase);
+
 /* This returns a pointer for the current ENGINE structure that
  * is (by default) performing any RSA operations. The value returned
  * is an incremented reference, so it should be free'd (ENGINE_finish)
@@ -310,6 +320,8 @@ void ERR_load_ENGINE_strings(void);
 #define ENGINE_F_ENGINE_INIT				 119
 #define ENGINE_F_ENGINE_LIST_ADD			 120
 #define ENGINE_F_ENGINE_LIST_REMOVE			 121
+#define ENGINE_F_ENGINE_LOAD_PRIVATE_KEY		 150
+#define ENGINE_F_ENGINE_LOAD_PUBLIC_KEY			 151
 #define ENGINE_F_ENGINE_NEW				 122
 #define ENGINE_F_ENGINE_REMOVE				 123
 #define ENGINE_F_ENGINE_SET_BN_MOD_EXP			 124
@@ -324,9 +336,13 @@ void ERR_load_ENGINE_strings(void);
 #define ENGINE_F_ENGINE_SET_NAME			 130
 #define ENGINE_F_ENGINE_SET_RAND			 131
 #define ENGINE_F_ENGINE_SET_RSA				 132
+#define ENGINE_F_ENGINE_UNLOAD_KEY			 152
 #define ENGINE_F_HWCRHK_CTRL				 143
 #define ENGINE_F_HWCRHK_FINISH				 135
+#define ENGINE_F_HWCRHK_GET_PASS			 155
 #define ENGINE_F_HWCRHK_INIT				 136
+#define ENGINE_F_HWCRHK_LOAD_PRIVKEY			 153
+#define ENGINE_F_HWCRHK_LOAD_PUBKEY			 154
 #define ENGINE_F_HWCRHK_MOD_EXP				 137
 #define ENGINE_F_HWCRHK_MOD_EXP_CRT			 138
 #define ENGINE_F_HWCRHK_RAND_BYTES			 139
@@ -338,6 +354,7 @@ void ERR_load_ENGINE_strings(void);
 #define ENGINE_R_BIO_WAS_FREED				 121
 #define ENGINE_R_BN_CTX_FULL				 101
 #define ENGINE_R_BN_EXPAND_FAIL				 102
+#define ENGINE_R_CHIL_ERROR				 123
 #define ENGINE_R_CONFLICTING_ENGINE_ID			 103
 #define ENGINE_R_CTRL_COMMAND_NOT_IMPLEMENTED		 119
 #define ENGINE_R_DSO_FAILURE				 104
@@ -350,8 +367,12 @@ void ERR_load_ENGINE_strings(void);
 #define ENGINE_R_MISSING_KEY_COMPONENTS			 111
 #define ENGINE_R_NOT_INITIALISED			 117
 #define ENGINE_R_NOT_LOADED				 112
+#define ENGINE_R_NO_CALLBACK				 127
 #define ENGINE_R_NO_CONTROL_FUNCTION			 120
+#define ENGINE_R_NO_KEY					 124
+#define ENGINE_R_NO_LOAD_FUNCTION			 125
 #define ENGINE_R_NO_SUCH_ENGINE				 116
+#define ENGINE_R_NO_UNLOAD_FUNCTION			 126
 #define ENGINE_R_PROVIDE_PARAMETERS			 113
 #define ENGINE_R_REQUEST_FAILED				 114
 #define ENGINE_R_REQUEST_FALLBACK			 118