Introduce RSAPrivateKey::SignDigest

crypto/rsa_private_key_openssl.cc

Index: crypto/rsa_private_key_openssl.cc
diff --git a/crypto/rsa_private_key_openssl.cc b/crypto/rsa_private_key_openssl.cc
index f191e393288372c98e4ec379f3408224d09b7480..4bdede0aa8949313d807a980d31f8e47fb6a7cd3 100644
--- a/crypto/rsa_private_key_openssl.cc
+++ b/crypto/rsa_private_key_openssl.cc
@@ -123,4 +123,15 @@ bool RSAPrivateKey::ExportPublicKey(std::vector<uint8>* output) const {
   return ExportKey(key_, i2d_PUBKEY_bio, output);
 }
 
+bool RSAPrivateKey::SignDigest(const std::vector<uint8>& digest,
+                               std::vector<uint8>* output) const {
+  RSA* rsa = EVP_PKEY_get1_RSA(key_);
+  if (!rsa)
+    return false;
+  output->resize(RSA_size(rsa));
+  unsigned int size;
+  return RSA_sign(NID_sha1, &digest[0], digest.size(), &(*output)[0], &size,
+                  rsa);
+}
+
 }  // namespace crypto