diff --git a/library/rsa.c b/library/rsa.c
index cde07e3..3f480a3 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -249,6 +249,9 @@
 {
     int ret = 0;
     int have_N, have_P, have_Q, have_D, have_E;
+#if !defined(MBEDTLS_RSA_NO_CRT)
+    int have_DP, have_DQ, have_QP;
+#endif
     int n_missing, pq_missing, d_missing, is_pub, is_priv;
 
     RSA_VALIDATE_RET( ctx != NULL );
@@ -259,6 +262,12 @@
     have_D = ( mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 );
     have_E = ( mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0 );
 
+#if !defined(MBEDTLS_RSA_NO_CRT)
+    have_DP = ( mbedtls_mpi_cmp_int( &ctx->DP, 0 ) != 0 );
+    have_DQ = ( mbedtls_mpi_cmp_int( &ctx->DQ, 0 ) != 0 );
+    have_QP = ( mbedtls_mpi_cmp_int( &ctx->QP, 0 ) != 0 );
+#endif
+
     /*
      * Check whether provided parameters are enough
      * to deduce all others. The following incomplete
@@ -324,7 +333,7 @@
      */
 
 #if !defined(MBEDTLS_RSA_NO_CRT)
-    if( is_priv )
+    if( is_priv && ! ( have_DP && have_DQ && have_QP ) )
     {
         ret = mbedtls_rsa_deduce_crt( &ctx->P,  &ctx->Q,  &ctx->D,
                                       &ctx->DP, &ctx->DQ, &ctx->QP );