Typos and doc additions
diff --git a/library/error.c b/library/error.c
index 4d7b81c..98fba5c 100644
--- a/library/error.c
+++ b/library/error.c
@@ -356,7 +356,7 @@
         if( use_ret == -(POLARSSL_ERR_RSA_KEY_GEN_FAILED) )
             polarssl_snprintf( buf, buflen, "RSA - Something failed during generation of a key" );
         if( use_ret == -(POLARSSL_ERR_RSA_KEY_CHECK_FAILED) )
-            polarssl_snprintf( buf, buflen, "RSA - Key failed to pass the libraries validity check" );
+            polarssl_snprintf( buf, buflen, "RSA - Key failed to pass the library's validity check" );
         if( use_ret == -(POLARSSL_ERR_RSA_PUBLIC_FAILED) )
             polarssl_snprintf( buf, buflen, "RSA - The public key operation failed" );
         if( use_ret == -(POLARSSL_ERR_RSA_PRIVATE_FAILED) )