diff --git a/library/ctr_drbg.c b/library/ctr_drbg.c
index a99ec00..c318e6a 100644
--- a/library/ctr_drbg.c
+++ b/library/ctr_drbg.c
@@ -336,17 +336,11 @@
     return( ret );
 }
 
-/*
- * Non-public function wrapped by mbedtls_ctr_drbg_seed(). Necessary to allow
- * NIST tests to succeed (which require known length fixed entropy)
- */
-int mbedtls_ctr_drbg_seed_entropy_len(
-                   mbedtls_ctr_drbg_context *ctx,
-                   int (*f_entropy)(void *, unsigned char *, size_t),
-                   void *p_entropy,
-                   const unsigned char *custom,
-                   size_t len,
-                   size_t entropy_len )
+int mbedtls_ctr_drbg_seed( mbedtls_ctr_drbg_context *ctx,
+                           int (*f_entropy)(void *, unsigned char *, size_t),
+                           void *p_entropy,
+                           const unsigned char *custom,
+                           size_t len )
 {
     int ret;
     unsigned char key[MBEDTLS_CTR_DRBG_KEYSIZE];
@@ -358,7 +352,8 @@
     ctx->f_entropy = f_entropy;
     ctx->p_entropy = p_entropy;
 
-    ctx->entropy_len = entropy_len;
+    if( ctx->entropy_len == 0 )
+        ctx->entropy_len = MBEDTLS_CTR_DRBG_ENTROPY_LEN;
     ctx->reseed_interval = MBEDTLS_CTR_DRBG_RESEED_INTERVAL;
 
     /*
@@ -376,14 +371,15 @@
     return( 0 );
 }
 
-int mbedtls_ctr_drbg_seed( mbedtls_ctr_drbg_context *ctx,
-                   int (*f_entropy)(void *, unsigned char *, size_t),
-                   void *p_entropy,
-                   const unsigned char *custom,
-                   size_t len )
+/* Backward compatibility wrapper */
+int mbedtls_ctr_drbg_seed_entropy_len(
+    mbedtls_ctr_drbg_context *ctx,
+    int (*f_entropy)(void *, unsigned char *, size_t), void *p_entropy,
+    const unsigned char *custom, size_t len,
+    size_t entropy_len )
 {
-    return( mbedtls_ctr_drbg_seed_entropy_len( ctx, f_entropy, p_entropy, custom, len,
-                                       MBEDTLS_CTR_DRBG_ENTROPY_LEN ) );
+    mbedtls_ctr_drbg_set_entropy_len( ctx, entropy_len );
+    return( mbedtls_ctr_drbg_seed( ctx, f_entropy, p_entropy, custom, len ) );
 }
 
 int mbedtls_ctr_drbg_random_with_add( void *p_rng,
@@ -617,8 +613,11 @@
         mbedtls_printf( "  CTR_DRBG (PR = TRUE) : " );
 
     test_offset = 0;
-    CHK( mbedtls_ctr_drbg_seed_entropy_len( &ctx, ctr_drbg_self_test_entropy,
-                                (void *) entropy_source_pr, nonce_pers_pr, 16, 32 ) );
+    mbedtls_ctr_drbg_set_entropy_len( &ctx, 32 );
+    CHK( mbedtls_ctr_drbg_seed( &ctx,
+                                ctr_drbg_self_test_entropy,
+                                (void *) entropy_source_pr,
+                                nonce_pers_pr, 16 ) );
     mbedtls_ctr_drbg_set_prediction_resistance( &ctx, MBEDTLS_CTR_DRBG_PR_ON );
     CHK( mbedtls_ctr_drbg_random( &ctx, buf, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
     CHK( mbedtls_ctr_drbg_random( &ctx, buf, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
@@ -638,8 +637,11 @@
     mbedtls_ctr_drbg_init( &ctx );
 
     test_offset = 0;
-    CHK( mbedtls_ctr_drbg_seed_entropy_len( &ctx, ctr_drbg_self_test_entropy,
-                            (void *) entropy_source_nopr, nonce_pers_nopr, 16, 32 ) );
+    mbedtls_ctr_drbg_set_entropy_len( &ctx, 32 );
+    CHK( mbedtls_ctr_drbg_seed( &ctx,
+                                ctr_drbg_self_test_entropy,
+                                (void *) entropy_source_nopr,
+                                nonce_pers_nopr, 16 ) );
     CHK( mbedtls_ctr_drbg_random( &ctx, buf, 16 ) );
     CHK( mbedtls_ctr_drbg_reseed( &ctx, NULL, 0 ) );
     CHK( mbedtls_ctr_drbg_random( &ctx, buf, 16 ) );