Certificate Transparency: Parse consistency proof JSON

Adding the ability to parse a consistency proof between two Signed Tree
Heads, as defined in http://tools.ietf.org/html/rfc6962#section-4.4.

BUG=506227

Review URL: https://codereview.chromium.org/1429163004

Cr-Commit-Position: refs/heads/master@{#358549}

2 files changed, 22 insertions, 0 deletions

diff --git a/net/test/ct_test_util.cc b/net/test/ct_test_util.cc
index 65a8122..3bd30ff 100644
--- a/net/test/ct_test_util.cc
+++ b/net/test/ct_test_util.cc
@@ -312,6 +312,23 @@ std::string CreateSignedTreeHeadJsonString(size_t tree_size,
   return sth_json;
 }
 
+std::string CreateConsistencyProofJsonString(
+    const std::vector<std::string>& raw_nodes) {
+  std::string consistency_proof_json = std::string("{\"consistency\":[");
+
+  for (auto it = raw_nodes.begin(); it != raw_nodes.end(); ++it) {
+    std::string proof_node_b64;
+    base::Base64Encode(*it, &proof_node_b64);
+    consistency_proof_json +=
+        base::StringPrintf("\"%s\"", proof_node_b64.c_str());
+    if (it + 1 != raw_nodes.end())
+      consistency_proof_json += std::string(",");
+  }
+  consistency_proof_json += std::string("]}");
+
+  return consistency_proof_json;
+}
+
 }  // namespace ct
 
 }  // namespace net
diff --git a/net/test/ct_test_util.h b/net/test/ct_test_util.h
index 5701a28..5bb2d7a 100644
--- a/net/test/ct_test_util.h
+++ b/net/test/ct_test_util.h
@@ -6,6 +6,7 @@
 #define NET_CERT_CT_TEST_UTIL_H_
 
 #include <string>
+#include <vector>
 
 #include "base/memory/ref_counted.h"
 
@@ -86,6 +87,10 @@ std::string CreateSignedTreeHeadJsonString(size_t tree_size,
                                            std::string sha256_root_hash,
                                            std::string tree_head_signature);
 
+// Assembles, and returns, a sample consistency proof in JSON format using
+// the provided raw nodes (i.e. the raw nodes will be base64-encoded).
+std::string CreateConsistencyProofJsonString(
+    const std::vector<std::string>& raw_nodes);
 }  // namespace ct
 
 }  // namespace net