diff --git a/library/pk_wrap.c b/library/pk_wrap.c
index 2c7d2d7..f9b4c65 100644
--- a/library/pk_wrap.c
+++ b/library/pk_wrap.c
@@ -66,7 +66,7 @@
 static size_t rsa_get_bitlen( const void *ctx )
 {
     const mbedtls_rsa_context * rsa = (const mbedtls_rsa_context *) ctx;
-    return( 8 * mbedtls_rsa_get_len( rsa ) );
+    return( mbedtls_rsa_get_bitlen( rsa ) );
 }
 
 static int rsa_verify_wrap( void *ctx, mbedtls_md_type_t md_alg,
diff --git a/library/rsa.c b/library/rsa.c
index 88c1cf1..ad19639 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -480,12 +480,19 @@
 /*
  * Get length in bytes of RSA modulus
  */
-
 size_t mbedtls_rsa_get_len( const mbedtls_rsa_context *ctx )
 {
     return( ctx->len );
 }
 
+/*
+ * Get length in bits of RSA modulus
+ */
+size_t mbedtls_rsa_get_bitlen( const mbedtls_rsa_context *ctx )
+{
+    return( mbedtls_mpi_bitlen( &ctx->N ) );
+}
+
 
 #if defined(MBEDTLS_GENPRIME)