diff --git a/src/core/trace_ds.c b/src/core/trace_ds.c
index 7fdfe6e..8680a3f 100644
--- a/src/core/trace_ds.c
+++ b/src/core/trace_ds.c
@@ -323,7 +323,7 @@ void trace_ansi_disc(H3270 *hSession)
 	hSession->trace_skipping = 1;
 }
 
-void lib3270_trace_data(H3270 *hSession, const char *msg, const char *data, size_t datalen)
+void lib3270_trace_data(H3270 *hSession, const char *msg, const unsigned char *data, size_t datalen)
 {
 	// 00000000001111111111222222222233333333334444444444555555555566666666667777777777
 	// 01234567890123456789012345678901234567890123456789012345678901234567890123456789
diff --git a/src/include/lib3270/trace.h b/src/include/lib3270/trace.h
index e542a2c..4a4ed17 100644
--- a/src/include/lib3270/trace.h
+++ b/src/include/lib3270/trace.h
@@ -129,7 +129,7 @@
 	 * @param datalen	Length of the data block.
 	 *
 	 */
-	LIB3270_EXPORT void lib3270_trace_data(H3270 *hSession, const char *msg, const char *data, size_t datalen);
+	LIB3270_EXPORT void lib3270_trace_data(H3270 *hSession, const char *msg, const unsigned char *data, size_t datalen);
 
 
 #ifdef __cplusplus
diff --git a/src/ssl/linux/ldap.c b/src/ssl/linux/ldap.c
index 7109ce5..789ab0f 100644
--- a/src/ssl/linux/ldap.c
+++ b/src/ssl/linux/ldap.c
@@ -212,7 +212,7 @@ LIB3270_INTERNAL X509_CRL * get_crl_using_ldap(H3270 *hSession, SSL_ERROR_MESSAG
 		lib3270_trace_data(
 			hSession,
 			"CRL Data received from LDAP server",
-			(const char *) value[0]->bv_val,
+			(const unsigned char *) value[0]->bv_val,
 			value[0]->bv_len
 		);
 	}
--
libgit2 0.21.2