crypto: change ECSignatureCreator defaults to match SPDY.

crypto/ec_signature_creator.h

Index: crypto/ec_signature_creator.h
diff --git a/crypto/ec_signature_creator.h b/crypto/ec_signature_creator.h
index b557daaf7b0193d8708fd705e77475572251f823..a9cb65b4d3d3e766791d809272aff2a14178ee23 100644
--- a/crypto/ec_signature_creator.h
+++ b/crypto/ec_signature_creator.h
@@ -5,6 +5,7 @@
 #ifndef CRYPTO_EC_SIGNATURE_CREATOR_H_
 #define CRYPTO_EC_SIGNATURE_CREATOR_H_
 
+#include <string>
 #include <vector>
 
 #include "base/basictypes.h"
@@ -31,7 +32,7 @@ class CRYPTO_EXPORT ECSignatureCreator {
 
   // Create an instance. The caller must ensure that the provided PrivateKey
   // instance outlives the created ECSignatureCreator.
-  // TODO(rch):  This is currently hard coded to use SHA1. Ideally, we should
+  // TODO(rch):  This is currently hard coded to use SHA256. Ideally, we should
   // pass in the hash algorithm identifier.
   static ECSignatureCreator* Create(ECPrivateKey* key);
 
@@ -50,6 +51,13 @@ class CRYPTO_EXPORT ECSignatureCreator {
   virtual bool Sign(const uint8* data,
                     int data_len,
                     std::vector<uint8>* signature) = 0;
+
+  // DecodeSignature converts from a DER encoded ECDSA-Sig-Value (as produced
+  // by Sign) to a `raw' ECDSA signature which consists of a pair of
+  // big-endian, zero-padded, 256-bit integers, r and s. On success it returns

[wtc, 2012/09/12 22:06:27]

The size of r and s depends on the ECPrivateKey object.
It is fine to say "256-bit" for now because I think we can
only create P-256 ECPrivateKeys.

It seems bad to use different types for input and output.
Is std::string more convenient for the SPDY code?

[agl, 2012/09/13 20:17:59]

I've changed the output to also be a std::vector<uint8>

+  // true and puts the raw signature into |out_raw_sig|.
+  virtual bool DecodeSignature(const std::vector<uint8>& signature,
+                               std::string* out_raw_sig) = 0;
 };
 
 }  // namespace crypto