diff --git a/libwvdrmengine/oemcrypto/test/oec_session_util.cpp b/libwvdrmengine/oemcrypto/test/oec_session_util.cpp
index a5775ea3..4fbc31ac 100644
--- a/libwvdrmengine/oemcrypto/test/oec_session_util.cpp
+++ b/libwvdrmengine/oemcrypto/test/oec_session_util.cpp
@@ -167,7 +167,7 @@ void dump_boringssl_error() {
   while (auto err = ERR_get_error()) {
     char buffer[120];
     ERR_error_string_n(err, buffer, sizeof(buffer));
-    cout << "BoringSSL Error -- " << buffer << "\n";
+    cerr << "BoringSSL Error -- " << buffer << "\n";
   }
 }
 
@@ -1486,7 +1486,7 @@ void Session::LoadOEMCert(bool verify_cert) {
     if (i == 0) {
       public_rsa_ = EVP_PKEY_get1_RSA(pubkey.get());
       if (!public_rsa_) {
-        cout << "d2i_RSAPrivateKey failed.\n";
+        cerr << "d2i_RSAPrivateKey failed.\n";
         dump_boringssl_error();
         ASSERT_TRUE(nullptr != public_rsa_);
       }
@@ -1538,7 +1538,7 @@ void Session::PreparePublicKey(const uint8_t* rsa_key, size_t rsa_key_length) {
   if (public_rsa_) RSA_free(public_rsa_);
   public_rsa_ = EVP_PKEY_get1_RSA(evp.get());
   if (!public_rsa_) {
-    cout << "d2i_RSAPrivateKey failed. ";
+    cerr << "d2i_RSAPrivateKey failed. ";
     dump_boringssl_error();
     FAIL() << "Could not parse public RSA key.";
   }
@@ -1640,7 +1640,7 @@ void Session::VerifyRSASignature(const vector<uint8_t>& message,
 bool Session::GenerateRSASessionKey(vector<uint8_t>* session_key,
                                     vector<uint8_t>* enc_session_key) {
   if (!public_rsa_) {
-    cout << "No public RSA key loaded in test code.\n";
+    cerr << "No public RSA key loaded in test code.\n";
     return false;
   }
   *session_key = wvcdm::a2b_hex("6fa479c731d2770b6a61a5d1420bb9d1");
@@ -1650,7 +1650,7 @@ bool Session::GenerateRSASessionKey(vector<uint8_t>* session_key,
       &(enc_session_key->front()), public_rsa_, RSA_PKCS1_OAEP_PADDING);
   int size = static_cast<int>(RSA_size(public_rsa_));
   if (status != size) {
-    cout << "GenerateRSASessionKey error encrypting session key.\n";
+    cerr << "GenerateRSASessionKey error encrypting session key.\n";
     dump_boringssl_error();
     return false;
   }