diff --git a/substract_wave.c b/substract_wave.c
index a44e5e5..bef211b 100644
--- a/substract_wave.c
+++ b/substract_wave.c
@@ -545,9 +545,9 @@ for(i = 0; i < header_size; i++)
 	*ptr = 0;
 	ptr++;
 	}
-strcpy(out_header -> main_chunk, "RIFF");
-strcpy(out_header -> chunk_type, "WAVE"); 
-strcpy(out_header -> sub_chunk, "fmt ");
+memcpy(out_header -> main_chunk, "RIFF", 4);
+memcpy(out_header -> chunk_type, "WAVE", 4);
+memcpy(out_header -> sub_chunk, "fmt ", 4);
 out_header -> length_chunk = 16; //always 16
 out_header -> format = 1; //PCM
 
@@ -557,7 +557,7 @@ out_header -> byte_p_spl = main_header -> byte_p_spl;
 
 out_header -> sample_fq = main_header -> sample_fq;
 out_header -> bit_p_spl = 16; // main_header -> bit_p_spl;
-strcpy(out_header -> data_chunk, "data");
+memcpy(out_header -> data_chunk, "data", 4);
 
 main_offset = start_offset + (samples_offset * 2);