Further abstract API of verify crypto.

src/dnssec-crypto.h

@@ -0,0 +1,56 @@
+#ifndef DNSSEC_CRYPTO_H
+#define DNSSEC_CRYPTO_H
+
+/* 
+ * vtable for a signature verification algorithm.
+ *
+ * Each algorithm verifies that a certain signature over a (possibly non-contigous)
+ * array of data has been made with the specified key.
+ *
+ * Sample of usage:
+ *
+ *    // First, set the signature we need to check. Notice: data is not copied
+ *    // nor consumed, so the pointer must stay valid.
+ *    alg->set_signature(sig, 16);
+ *
+ *    // Second, push the data in; data is consumed immediately, so the buffer
+ *    // can be freed or modified.
+ *    alg->begin_data();
+ *    alg->add_data(buf1, 123);
+ *    alg->add_data(buf2, 45);
+ *    alg->add_data(buf3, 678);
+ *    alg->end_data();
+ *
+ *    // Third, verify if we got the correct key for this signature.
+ *    alg->verify(key1, 16);
+ *    alg->verify(key2, 16);
+ */ 
+typedef struct
+{
+  int (*set_signature)(unsigned char *data, unsigned len);
+  void (*begin_data)(void);
+  void (*add_data)(void *data, unsigned len);
+  void (*end_data)(void);
+  int (*verify)(unsigned char *key, unsigned key_len);
+} VerifyAlg;
+
+#define DEFINE_VALG(alg) \
+  void alg ## _set_signature(unsigned char *data, unsigned len); \
+  void alg ## _begin_data(void); \
+  void alg ## _add_data(void *data, unsigned len); \
+  void alg ## _end_data(void); \
+  int alg ## _verify(unsigned char *key, unsigned key_len) \
+  /**/
+
+#define VALG_VTABLE(alg) { \
+  alg ## _set_signature, \
+  alg ## _begin_data, \
+  alg ## _add_data, \
+  alg ## _end_data, \
+  alg ## _verify \
+  } /**/
+
+/* Algorithm 5: RSASHA1 */
+DEFINE_VALG(rsasha1);
+
+#endif /* DNSSEC_CRYPTO_H */