prop220: Implement certificates and key storage/creation

For prop220, we have a new ed25519 certificate type. This patch
implements the code to create, parse, and validate those, along with
code for routers to maintain their own sets of certificates and
keys.  (Some parts of master identity key encryption are done, but
the implementation of that isn't finished)

1 files changed, 66 insertions, 0 deletions

diff --git a/src/or/torcert.h b/src/or/torcert.h
new file mode 100644
index 0000000000..7e9c3f5b2d
--- /dev/null
+++ b/src/or/torcert.h
@@ -0,0 +1,66 @@
+/* Copyright (c) 2014, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TORCERT_H_INCLUDED
+#define TORCERT_H_INCLUDED
+
+#include "crypto_ed25519.h"
+
+#define SIGNED_KEY_TYPE_ED25519 0x01
+
+#define CERT_TYPE_ID_SIGNING    0x04
+#define CERT_TYPE_SIGNING_LINK  0x05
+#define CERT_TYPE_SIGNING_AUTH  0x06
+
+#define CERT_FLAG_INCLUDE_SIGNING_KEY 0x1
+
+/** An ed25519-signed certificate as used throughout the Tor protocol.
+ **/
+typedef struct tor_cert_st {
+  /** The key authenticated by this certificate */
+  ed25519_public_key_t signed_key;
+  /** The key that signed this certificate. This value may be unset if the
+   * certificate has never been checked, and didn't include its own key. */
+  ed25519_public_key_t signing_key;
+  /** A time after which this certificate will no longer be valid. */
+  time_t valid_until;
+
+  /** The encoded representation of this certificate */
+  uint8_t *encoded;
+  /** The length of <b>encoded</b> */
+  size_t encoded_len;
+
+  /** One of CERT_TYPE_... */
+  uint8_t cert_type;
+  /** True iff we received a signing key embedded in this certificate */
+  unsigned signing_key_included : 1;
+  /** True iff we checked the signature and found it bad */
+  unsigned sig_bad : 1;
+  /** True iff we checked the signature and found it correct */
+  unsigned sig_ok : 1;
+  /** True iff we checked the signature and first found that the cert
+   * had expired */
+  unsigned cert_expired : 1;
+  /** True iff we checked the signature and found the whole cert valid */
+  unsigned cert_valid : 1;
+} tor_cert_t;
+
+tor_cert_t *tor_cert_create(const ed25519_keypair_t *signing_key,
+                            uint8_t cert_type,
+                            const ed25519_public_key_t *signed_key,
+                            time_t now, time_t lifetime,
+                            uint32_t flags);
+
+tor_cert_t *tor_cert_parse(const uint8_t *cert, size_t certlen);
+
+void tor_cert_free(tor_cert_t *cert);
+
+int tor_cert_get_checkable_sig(ed25519_checkable_t *checkable_out,
+                                 const tor_cert_t *out,
+                                 const ed25519_public_key_t *pubkey);
+
+int tor_cert_checksig(tor_cert_t *cert,
+                      const ed25519_public_key_t *pubkey, time_t now);
+
+#endif
+