Add ECDSA signature primitive.
diff --git a/include/polarssl/ecdsa.h b/include/polarssl/ecdsa.h
index 39a0626..2ad986d 100644
--- a/include/polarssl/ecdsa.h
+++ b/include/polarssl/ecdsa.h
@@ -53,6 +53,24 @@
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );
/**
+ * \brief Verify ECDSA signature of a previously hashed message
+ *
+ * \param grp ECP group
+ * \param buf Message hash
+ * \param blen Length of buf
+ * \param Q Public key to use for verification
+ * \param r First integer of the signature
+ * \param s Second integer of the signature
+ *
+ * \return 0 if successful,
+ * POLARSSL_ERR_ECP_BAD_INPUT_DATA if signature is invalid
+ * or a POLARSSL_ERR_ECP_XXX or POLARSSL_MPI_XXX error code
+ */
+int ecdsa_verify( const ecp_group *grp,
+ const unsigned char *buf, size_t blen,
+ const ecp_point *Q, const mpi *r, const mpi *s);
+
+/**
* \brief Checkup routine
*
* \return 0 if successful, or 1 if the test failed