diff --git a/tests/crypto/mbedtls/prj.conf b/tests/crypto/mbedtls/prj.conf
index ed8ee98164..a572aece6e 100644
--- a/tests/crypto/mbedtls/prj.conf
+++ b/tests/crypto/mbedtls/prj.conf
@@ -5,3 +5,4 @@ CONFIG_MBEDTLS_CFG_FILE="config-tls-generic.h"
 CONFIG_MBEDTLS_TEST=y
 CONFIG_ZTEST=y
 CONFIG_TEST_USERSPACE=y
+CONFIG_MINIMAL_LIBC_RAND=y
diff --git a/tests/crypto/mbedtls/src/mbedtls.c b/tests/crypto/mbedtls/src/mbedtls.c
index 0d7f0c8cd9..06d6f0c065 100644
--- a/tests/crypto/mbedtls/src/mbedtls.c
+++ b/tests/crypto/mbedtls/src/mbedtls.c
@@ -72,20 +72,6 @@
 #include "mbedtls/memory_buffer_alloc.h"
 #endif
 
-#if defined(MBEDTLS_RSA_C)
-int rand(void)
-{
-	static ZTEST_DMEM uint32_t seed = 7U;
-
-	seed ^= seed << 13;
-	seed ^= seed >> 17;
-	seed ^= seed << 5;
-
-	return seed;
-}
-
-#endif
-
 static int test_snprintf(size_t n, const char ref_buf[10], int ref_ret)
 {
 	int ret;