diff --git a/src/liblzma/common/index.h b/src/liblzma/common/index.h
index 64e9724..ea39671 100644
--- a/src/liblzma/common/index.h
+++ b/src/liblzma/common/index.h
@@ -22,6 +22,9 @@
 /// Maximum Unpadded Size
 #define UNPADDED_SIZE_MAX (LZMA_VLI_MAX & ~LZMA_VLI_C(3))
 
+/// Index Indicator based on xz specification
+#define INDEX_INDICATOR 0
+
 
 /// Get the size of the Index Padding field. This is needed by Index encoder
 /// and decoder, but applications should have no use for this.
diff --git a/src/liblzma/common/index_decoder.c b/src/liblzma/common/index_decoder.c
index b268988..8622b2f 100644
--- a/src/liblzma/common/index_decoder.c
+++ b/src/liblzma/common/index_decoder.c
@@ -80,7 +80,7 @@ index_decode(void *coder_ptr, const lzma_allocator *allocator,
 		// format". One could argue that the application should
 		// verify the Index Indicator before trying to decode the
 		// Index, but well, I suppose it is simpler this way.
-		if (in[(*in_pos)++] != 0x00)
+		if (in[(*in_pos)++] != INDEX_INDICATOR)
 			return LZMA_DATA_ERROR;
 
 		coder->sequence = SEQ_COUNT;
diff --git a/src/liblzma/common/index_encoder.c b/src/liblzma/common/index_encoder.c
index ac97d0c..c7cafb7 100644
--- a/src/liblzma/common/index_encoder.c
+++ b/src/liblzma/common/index_encoder.c
@@ -65,7 +65,7 @@ index_encode(void *coder_ptr,
 	while (*out_pos < out_size)
 	switch (coder->sequence) {
 	case SEQ_INDICATOR:
-		out[*out_pos] = 0x00;
+		out[*out_pos] = INDEX_INDICATOR;
 		++*out_pos;
 		coder->sequence = SEQ_COUNT;
 		break;
diff --git a/src/liblzma/common/index_hash.c b/src/liblzma/common/index_hash.c
index 34df85d..c3c5667 100644
--- a/src/liblzma/common/index_hash.c
+++ b/src/liblzma/common/index_hash.c
@@ -190,7 +190,7 @@ lzma_index_hash_decode(lzma_index_hash *index_hash, const uint8_t *in,
 	switch (index_hash->sequence) {
 	case SEQ_BLOCK:
 		// Check the Index Indicator is present.
-		if (in[(*in_pos)++] != 0x00)
+		if (in[(*in_pos)++] != INDEX_INDICATOR)
 			return LZMA_DATA_ERROR;
 
 		index_hash->sequence = SEQ_COUNT;
diff --git a/src/liblzma/common/stream_decoder.c b/src/liblzma/common/stream_decoder.c
index dcf7c14..6428381 100644
--- a/src/liblzma/common/stream_decoder.c
+++ b/src/liblzma/common/stream_decoder.c
@@ -12,6 +12,7 @@
 
 #include "stream_decoder.h"
 #include "block_decoder.h"
+#include "index.h"
 
 
 typedef struct {
@@ -164,7 +165,7 @@ stream_decode(void *coder_ptr, const lzma_allocator *allocator,
 
 		if (coder->pos == 0) {
 			// Detect if it's Index.
-			if (in[*in_pos] == 0x00) {
+			if (in[*in_pos] == INDEX_INDICATOR) {
 				coder->sequence = SEQ_INDEX;
 				break;
 			}
diff --git a/src/liblzma/common/stream_decoder_mt.c b/src/liblzma/common/stream_decoder_mt.c
index 5733c76..fd5cd7f 100644
--- a/src/liblzma/common/stream_decoder_mt.c
+++ b/src/liblzma/common/stream_decoder_mt.c
@@ -887,7 +887,7 @@ decode_block_header(struct lzma_stream_coder *coder,
 
 	if (coder->pos == 0) {
 		// Detect if it's Index.
-		if (in[*in_pos] == 0x00)
+		if (in[*in_pos] == INDEX_INDICATOR)
 			return LZMA_INDEX_DETECTED;
 
 		// Calculate the size of the Block Header. Note that