diff --git a/igzip/Makefile.am b/igzip/Makefile.am
index a060b0a..85d0c05 100644
--- a/igzip/Makefile.am
+++ b/igzip/Makefile.am
@@ -59,7 +59,8 @@ lsrc_x86_64 +=  \
 		igzip/igzip_inflate_multibinary.asm \
 		igzip/encode_df_04.asm \
 		igzip/encode_df_06.asm \
-		igzip/proc_heap.asm
+		igzip/proc_heap.asm \
+		igzip/igzip_deflate_hash.asm
 
 src_include += -I $(srcdir)/igzip
 extern_hdrs +=	include/igzip_lib.h
diff --git a/igzip/data_struct2.asm b/igzip/data_struct2.asm
index 06ef8f5..56d304f 100644
--- a/igzip/data_struct2.asm
+++ b/igzip/data_struct2.asm
@@ -222,4 +222,10 @@ _STORED_BLK		equ 0
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+IGZIP_NO_HIST		equ 0
+IGZIP_HIST		equ 1
+IGZIP_DICT_HIST		equ 2
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
diff --git a/igzip/igzip.c b/igzip/igzip.c
index 4ba52e7..189955c 100644
--- a/igzip/igzip.c
+++ b/igzip/igzip.c
@@ -66,6 +66,7 @@
 # define to_be32(x) _byteswap_ulong(x)
 #endif
 
+extern void isal_deflate_hash_lvl0(struct isal_zstream *stream, uint8_t * dict, int dict_len);
 extern const uint8_t gzip_hdr[];
 extern const uint32_t gzip_hdr_bytes;
 extern const uint32_t gzip_trl_bytes;
@@ -125,6 +126,9 @@ struct slver isal_deflate_stateless_slver = { 0x0083, 0x01, 0x01 };
 struct slver isal_deflate_set_hufftables_slver_00_01_008b;
 struct slver isal_deflate_set_hufftables_slver = { 0x008b, 0x01, 0x00 };
 
+struct slver isal_deflate_set_dict_slver_00_01_008c;
+struct slver isal_deflate_set_dict_slver = { 0x008c, 0x01, 0x00 };
+
 /*****************************************************************/
 
 // isal_adler32_bam1 - adler with (B | A minus 1) storage
@@ -188,7 +192,7 @@ void sync_flush(struct isal_zstream *stream)
 		if (stream->flush == FULL_FLUSH) {
 			/* Clear match history so there are no cross
 			 * block length distance pairs */
-			reset_match_history(stream);
+			state->has_hist = IGZIP_NO_HIST;
 		}
 	}
 }
@@ -757,7 +761,7 @@ static inline void reset_match_history(struct isal_zstream *stream)
 	uint16_t *head = stream->internal_state.head;
 	int i = 0;
 
-	state->has_hist = 0;
+	state->has_hist = IGZIP_NO_HIST;
 
 	if ((stream->total_in & 0xFFFF) == 0)
 		memset(stream->internal_state.head, 0, sizeof(stream->internal_state.head));
@@ -786,21 +790,17 @@ void isal_deflate_init(struct isal_zstream *stream)
 	state->b_bytes_processed = 0;
 	state->has_eob = 0;
 	state->has_eob_hdr = 0;
-	state->has_hist = 0;
+	state->has_hist = IGZIP_NO_HIST;
 	state->state = ZSTATE_NEW_HDR;
 	state->count = 0;
 
 	state->tmp_out_start = 0;
 	state->tmp_out_end = 0;
 
-	state->file_start = stream->next_in;
-
 	init(&state->bitbuf);
 
 	state->crc = 0;
 
-	memset(state->head, 0, sizeof(state->head));
-
 	return;
 }
 
@@ -844,6 +844,40 @@ void isal_deflate_stateless_init(struct isal_zstream *stream)
 	return;
 }
 
+void isal_deflate_hash(struct isal_zstream *stream, uint8_t * dict, uint32_t dict_len)
+{
+	isal_deflate_hash_lvl0(stream, dict, dict_len);
+	stream->internal_state.has_hist = IGZIP_HIST;
+}
+
+int isal_deflate_set_dict(struct isal_zstream *stream, uint8_t * dict, uint32_t dict_len)
+{
+	struct isal_zstate *state = &stream->internal_state;
+
+	if (state->state != ZSTATE_NEW_HDR || state->b_bytes_processed != state->b_bytes_valid)
+		return ISAL_INVALID_STATE;
+
+	if (dict_len <= 0)
+		return COMP_OK;
+
+	if (dict_len > IGZIP_HIST_SIZE) {
+		dict = dict + dict_len - IGZIP_HIST_SIZE;
+		dict_len = IGZIP_HIST_SIZE;
+	}
+
+	memcpy(state->buffer, dict, dict_len);
+	state->b_bytes_processed = dict_len;
+	state->b_bytes_valid = dict_len;
+
+	/* Reset history to prevent out of bounds matches this works because
+	 * dictionary must set at least 1 element in the history */
+	memset(stream->internal_state.head, -1, sizeof(stream->internal_state.head));
+
+	state->has_hist = IGZIP_DICT_HIST;
+
+	return COMP_OK;
+}
+
 int isal_deflate_stateless(struct isal_zstream *stream)
 {
 	uint8_t *next_in = stream->next_in;
@@ -963,6 +997,11 @@ int isal_deflate(struct isal_zstream *stream)
 	avail_in = stream->avail_in;
 	stream->total_in -= state->b_bytes_valid - state->b_bytes_processed;
 
+	if (state->has_hist == IGZIP_NO_HIST)
+		reset_match_history(stream);
+	else if (state->has_hist == IGZIP_DICT_HIST)
+		isal_deflate_hash(stream, state->buffer, state->b_bytes_processed);
+
 	do {
 		size = avail_in;
 		if (size > sizeof(state->buffer) - state->b_bytes_valid) {
diff --git a/igzip/igzip_base.c b/igzip/igzip_base.c
index 0e2b705..d5720eb 100644
--- a/igzip/igzip_base.c
+++ b/igzip/igzip_base.c
@@ -208,3 +208,22 @@ void isal_deflate_finish_base(struct isal_zstream *stream)
 
 	return;
 }
+
+void isal_deflate_hash_lvl0_base(struct isal_zstream *stream, uint8_t * dict,
+				 uint32_t dict_len)
+{
+	uint8_t *next_in = dict;
+	uint8_t *end_in = dict + dict_len - SHORTEST_MATCH;
+	uint32_t literal;
+	uint32_t hash;
+	uint16_t lookup_val = stream->total_in - dict_len;
+	uint16_t *last_seen = stream->internal_state.head;
+
+	while (next_in <= end_in) {
+		literal = *(uint32_t *) next_in;
+		hash = compute_hash(literal) & HASH_MASK;
+		last_seen[hash] = lookup_val;
+		lookup_val++;
+		next_in++;
+	}
+}
diff --git a/igzip/igzip_base_aliases.c b/igzip/igzip_base_aliases.c
index 92b550f..ad2a406 100644
--- a/igzip/igzip_base_aliases.c
+++ b/igzip/igzip_base_aliases.c
@@ -43,6 +43,8 @@ struct deflate_icf *encode_deflate_icf_base(struct deflate_icf *next_in,
 uint32_t crc32_gzip_base(uint32_t init_crc, const unsigned char *buf, uint64_t len);
 uint32_t adler32_base(uint32_t init, const unsigned char *buf, uint64_t len);
 int decode_huffman_code_block_stateless_base(struct inflate_state *s);
+void isal_deflate_hash_lvl0_base(struct isal_zstream *stream, uint8_t * dict,
+				 uint32_t dict_len);
 
 void isal_deflate_body(struct isal_zstream *stream)
 {
@@ -91,3 +93,8 @@ int decode_huffman_code_block_stateless(struct inflate_state *s)
 {
 	return decode_huffman_code_block_stateless_base(s);
 }
+
+void isal_deflate_hash_lvl0(struct isal_zstream *stream, uint8_t * dict, uint32_t dict_len)
+{
+	return isal_deflate_hash_lvl0_base(stream, dict, dict_len);
+}
diff --git a/igzip/igzip_body.asm b/igzip/igzip_body.asm
index e588af6..3a84d02 100644
--- a/igzip/igzip_body.asm
+++ b/igzip/igzip_body.asm
@@ -212,7 +212,7 @@ MARK __body_compute_hash_ %+ ARCH
 	and	hash, HASH_MASK
 	and	hash2, HASH_MASK
 
-	cmp	dword [stream + _internal_state_has_hist], 0
+	cmp	dword [stream + _internal_state_has_hist], IGZIP_NO_HIST
 	je	write_first_byte
 
 	jmp	loop2
@@ -545,7 +545,7 @@ write_first_byte:
 	cmp	m_out_buf, [stream + _internal_state_bitbuf_m_out_end]
 	ja	output_end
 
-	mov	dword [stream + _internal_state_has_hist], 1
+	mov	dword [stream + _internal_state_has_hist], IGZIP_HIST
 
 	mov	[stream + _internal_state_head + 2 * hash], f_i %+ w
 
diff --git a/igzip/igzip_decode_block_stateless.asm b/igzip/igzip_decode_block_stateless.asm
index b048223..7f92c63 100644
--- a/igzip/igzip_decode_block_stateless.asm
+++ b/igzip/igzip_decode_block_stateless.asm
@@ -363,6 +363,7 @@ decode_huffman_code_block_stateless_ %+ ARCH %+ :
 	mov	dword [state + _copy_overflow_dist], 0
 
 	mov	tmp3 %+ d, dword [state + _total_out]
+	add	tmp3 %+ d, dword [state + _dict_length]
 	sub	tmp3, next_out
 	neg	tmp3
 
@@ -658,6 +659,7 @@ end:
 	sub	end_out, next_out
 	mov	dword [state + _avail_out], end_out %+ d
 	sub	next_out, [rsp + start_out_mem_offset]
+	sub	next_out %+ d, [state + _dict_length]
 	mov	[state + _total_out], next_out %+ d
 	mov	[state + _next_in], next_in
 	sub	end_in, next_in
diff --git a/igzip/igzip_deflate_hash.asm b/igzip/igzip_deflate_hash.asm
new file mode 100644
index 0000000..162014e
--- /dev/null
+++ b/igzip/igzip_deflate_hash.asm
@@ -0,0 +1,61 @@
+%include "options.asm"
+%include "lz0a_const.asm"
+%include "data_struct2.asm"
+%include "huffman.asm"
+%include "reg_sizes.asm"
+
+%define DICT_SLOP 4
+
+%ifidn __OUTPUT_FORMAT__, win64
+%define arg1 rcx
+%define arg2 rdx
+%define arg3 r8
+%else
+%define arg1 rdi
+%define arg2 rsi
+%define arg3 rdx
+%endif
+
+%define stream arg1
+
+%define dict_offset arg2
+
+%define dict_len arg3
+%define f_i arg3
+
+%define data r9
+
+%define hash r10
+
+%define f_i_end r11
+
+global isal_deflate_hash_lvl0_01
+isal_deflate_hash_lvl0_01:
+%ifnidn (arg1, stream)
+	mov stream, arg1
+%endif
+%ifnidn (arg2, dict_next)
+	mov dict_offset, arg2
+%endif
+
+	mov	f_i_end %+ d, dword [stream + _total_in]
+	neg	f_i
+	add	f_i, f_i_end
+
+	sub	dict_offset, f_i
+
+	sub	f_i_end, DICT_SLOP
+	cmp	f_i, f_i_end
+	jg	end
+
+main_loop:
+	mov	data %+ d, [f_i + dict_offset]
+	compute_hash	hash, data
+	and	hash, HASH_MASK
+	mov	[stream + _internal_state_head + 2 * hash], f_i %+ w
+
+	add	f_i, 1
+	cmp	f_i, f_i_end
+	jle	main_loop
+end:
+	ret
diff --git a/igzip/igzip_file_perf.c b/igzip/igzip_file_perf.c
index 828fe80..08a0540 100644
--- a/igzip/igzip_file_perf.c
+++ b/igzip/igzip_file_perf.c
@@ -52,26 +52,31 @@ int usage(void)
 		"  -X        use compression level X with 0 <= X <= 1\n"
 		"  -b <size> input buffer size, 0 buffers all the input\n"
 		"  -i <iter> number of iterations (at least 1)\n"
-		"  -o <file> output file for compresed data\n");
+		"  -o <file> output file for compresed data\n"
+		"  -d <file> dictionary file used by compression\n");
+
 	exit(0);
 }
 
 int main(int argc, char *argv[])
 {
-	FILE *in = NULL, *out = NULL;
-	unsigned char *inbuf, *outbuf, *level_buf = NULL;
+	FILE *in = NULL, *out = NULL, *dict = NULL;
+	unsigned char *inbuf, *outbuf, *level_buf = NULL, *dictbuf = NULL;
 	int i, c, iterations = 0, inbuf_size = 0;
-	uint64_t infile_size, outbuf_size;
+	uint64_t infile_size, outbuf_size, dictfile_size;
 	struct isal_huff_histogram histogram;
 	struct isal_hufftables hufftables_custom;
 	int level = 0, level_size = 0, avail_in;
-	char *in_file_name = NULL, *out_file_name = NULL;
+	char *in_file_name = NULL, *out_file_name = NULL, *dict_file_name = NULL;
 
-	while ((c = getopt(argc, argv, "h01i:b:o:")) != -1) {
+	while ((c = getopt(argc, argv, "h01i:b:o:d:")) != -1) {
 		switch (c) {
 		case 'o':
 			out_file_name = optarg;
 			break;
+		case 'd':
+			dict_file_name = optarg;
+			break;
 		case 'i':
 			iterations = atoi(optarg);
 			if (iterations < 1)
@@ -112,6 +117,15 @@ int main(int argc, char *argv[])
 		printf("outfile=%s\n", out_file_name);
 	}
 
+	if (dict_file_name != NULL) {
+		dict = fopen(dict_file_name, "rb");
+		if (!dict) {
+			fprintf(stderr, "Can't open %s for reading\n", dict_file_name);
+			exit(0);
+		}
+		printf("outfile=%s\n", dict_file_name);
+	}
+
 	printf("Window Size: %d K\n", IGZIP_HIST_SIZE / 1024);
 	printf("igzip_file_perf: \n");
 	fflush(0);
@@ -123,6 +137,10 @@ int main(int argc, char *argv[])
 
 	outbuf_size = 2 * infile_size + BUF_SIZE;
 
+	dictfile_size = 0;
+	if (dict_file_name != NULL)
+		dictfile_size = get_filesize(dict);
+
 	if (iterations == 0) {
 		iterations = infile_size ? RUN_MEM_SIZE / infile_size : MIN_TEST_LOOPS;
 		if (iterations < MIN_TEST_LOOPS)
@@ -140,6 +158,14 @@ int main(int argc, char *argv[])
 		exit(0);
 	}
 
+	if (dictfile_size != 0) {
+		dictbuf = malloc(dictfile_size);
+		if (dictbuf == NULL) {
+			fprintf(stderr, "Can't allocate dictionary buffer memory\n");
+			exit(0);
+		}
+	}
+
 	if (level_size != 0) {
 		level_buf = malloc(level_size);
 		if (level_buf == NULL) {
@@ -158,11 +184,18 @@ int main(int argc, char *argv[])
 		exit(0);
 	}
 
+	if (dictfile_size != (uint32_t) fread(dictbuf, 1, dictfile_size, dict)) {
+		fprintf(stderr, "Couldn't fit all of dictionary file into buffer\n");
+		exit(0);
+	}
+
 	struct perf start, stop;
 	perf_start(&start);
 
 	for (i = 0; i < iterations; i++) {
 		isal_deflate_init(&stream);
+		if (dict_file_name != NULL)
+			isal_deflate_set_dict(&stream, dictbuf, dictfile_size);
 		stream.end_of_stream = 0;
 		stream.flush = NO_FLUSH;
 		stream.level = level;
diff --git a/igzip/igzip_finish.asm b/igzip/igzip_finish.asm
index e8d5e36..dbbe0d9 100644
--- a/igzip/igzip_finish.asm
+++ b/igzip/igzip_finish.asm
@@ -126,7 +126,7 @@ skip_SLOP:
 
 	mov	curr_data %+ d, [file_start + f_i]
 
-	cmp	dword [stream + _internal_state_has_hist], 0
+	cmp	dword [stream + _internal_state_has_hist], IGZIP_NO_HIST
 	jne	skip_write_first_byte
 
 	cmp	m_out_buf, [stream + _internal_state_bitbuf_m_out_end]
@@ -135,7 +135,7 @@ skip_SLOP:
 	compute_hash	hash, curr_data
 	and	hash %+ d, HASH_MASK
 	mov	[stream + _internal_state_head + 2 * hash], f_i %+ w
-	mov	dword [stream + _internal_state_has_hist], 1
+	mov	dword [stream + _internal_state_has_hist], IGZIP_HIST
 	jmp	encode_literal
 
 skip_write_first_byte:
diff --git a/igzip/igzip_icf_body.asm b/igzip/igzip_icf_body.asm
index bc76114..abfc814 100644
--- a/igzip/igzip_icf_body.asm
+++ b/igzip/igzip_icf_body.asm
@@ -193,7 +193,7 @@ MARK __body_compute_hash_ %+ ARCH
 	and	hash, HASH_MASK
 	and	hash2, HASH_MASK
 
-	cmp	dword [stream + _internal_state_has_hist], 0
+	cmp	dword [stream + _internal_state_has_hist], IGZIP_NO_HIST
 	je	write_first_byte
 
 	jmp	loop2
@@ -482,7 +482,7 @@ write_first_byte:
 	cmp	m_out_buf, [rsp + m_out_end]
 	ja	output_end
 
-	mov	dword [stream + _internal_state_has_hist], 1
+	mov	dword [stream + _internal_state_has_hist], IGZIP_HIST
 
 	mov	[stream + _internal_state_head + 2 * hash], f_i %+ w
 
diff --git a/igzip/igzip_icf_finish.asm b/igzip/igzip_icf_finish.asm
index 2d65a61..15be09c 100644
--- a/igzip/igzip_icf_finish.asm
+++ b/igzip/igzip_icf_finish.asm
@@ -122,7 +122,7 @@ isal_deflate_icf_finish_01:
 
 	mov	curr_data %+ d, [file_start + f_i]
 
-	cmp	dword [stream + _internal_state_has_hist], 0
+	cmp	dword [stream + _internal_state_has_hist], IGZIP_NO_HIST
 	jne	skip_write_first_byte
 
 	cmp	m_out_buf, [rsp + m_out_end]
@@ -131,7 +131,7 @@ isal_deflate_icf_finish_01:
 	compute_hash	hash, curr_data
 	and	hash %+ d, HASH_MASK
 	mov	[stream + _internal_state_head + 2 * hash], f_i %+ w
-	mov	dword [stream + _internal_state_has_hist], 1
+	mov	dword [stream + _internal_state_has_hist], IGZIP_HIST
 	jmp	encode_literal
 
 skip_write_first_byte:
diff --git a/igzip/igzip_inflate.c b/igzip/igzip_inflate.c
index fe3b984..1fcf654 100644
--- a/igzip/igzip_inflate.c
+++ b/igzip/igzip_inflate.c
@@ -87,6 +87,9 @@ struct slver isal_inflate_stateless_slver = { 0x0089, 0x01, 0x00 };
 struct slver isal_inflate_slver_0001008a;
 struct slver isal_inflate_slver = { 0x008a, 0x01, 0x00 };
 
+struct slver isal_inflate_set_dict_slver_0001008d;
+struct slver isal_inflate_set_dict_slver = { 0x008d, 0x01, 0x00 };
+
 /*Performs a copy of length repeat_length data starting at dest -
  * lookback_distance into dest. This copy copies data previously copied when the
  * src buffer and the dest buffer overlap. */
@@ -1064,7 +1067,7 @@ int decode_huffman_code_block_stateless_base(struct inflate_state *state)
 				return ISAL_END_INPUT;
 			}
 
-			if (look_back_dist > state->total_out)
+			if (look_back_dist > state->total_out + state->dict_length)
 				return ISAL_INVALID_LOOKBACK;
 
 			if (state->avail_out < repeat_length) {
@@ -1103,6 +1106,7 @@ void isal_inflate_init(struct inflate_state *state)
 	state->next_out = NULL;
 	state->avail_out = 0;
 	state->total_out = 0;
+	state->dict_length = 0;
 	state->block_state = ISAL_BLOCK_NEW_HDR;
 	state->bfinal = 0;
 	state->crc_flag = 0;
@@ -1115,6 +1119,26 @@ void isal_inflate_init(struct inflate_state *state)
 	state->tmp_out_valid = 0;
 }
 
+int isal_inflate_set_dict(struct inflate_state *state, uint8_t * dict, uint32_t dict_len)
+{
+
+	if (state->block_state != ISAL_BLOCK_NEW_HDR
+	    || state->tmp_out_processed != state->tmp_out_valid)
+		return ISAL_INVALID_STATE;
+
+	if (dict_len > IGZIP_HIST_SIZE) {
+		dict = dict + dict_len - IGZIP_HIST_SIZE;
+		dict_len = IGZIP_HIST_SIZE;
+	}
+
+	memcpy(state->tmp_out_buffer, dict, dict_len);
+	state->tmp_out_processed = dict_len;
+	state->tmp_out_valid = dict_len;
+	state->dict_length = dict_len;
+
+	return COMP_OK;
+}
+
 int isal_inflate_stateless(struct inflate_state *state)
 {
 	uint32_t ret = 0;
@@ -1123,6 +1147,7 @@ int isal_inflate_stateless(struct inflate_state *state)
 	state->read_in = 0;
 	state->read_in_length = 0;
 	state->block_state = ISAL_BLOCK_NEW_HDR;
+	state->dict_length = 0;
 	state->bfinal = 0;
 	state->crc = 0;
 	state->total_out = 0;
diff --git a/igzip/igzip_multibinary.asm b/igzip/igzip_multibinary.asm
index 516be0e..52df6d3 100644
--- a/igzip/igzip_multibinary.asm
+++ b/igzip/igzip_multibinary.asm
@@ -71,6 +71,9 @@ extern adler32_base
 extern adler32_avx2_4
 extern adler32_sse
 
+extern isal_deflate_hash_lvl0_base
+extern isal_deflate_hash_lvl0_01
+
 section .text
 
 %include "multibinary.asm"
@@ -101,3 +104,6 @@ mbin_dispatch_init5	crc32_gzip, crc32_gzip_base, crc32_gzip_base, crc32_gzip_01,
 
 mbin_interface		isal_adler32
 mbin_dispatch_init5	isal_adler32, adler32_base, adler32_sse, adler32_sse, adler32_avx2_4
+
+mbin_interface		isal_deflate_hash_lvl0
+mbin_dispatch_init5	isal_deflate_hash_lvl0, isal_deflate_hash_lvl0_base, isal_deflate_hash_lvl0_01, isal_deflate_hash_lvl0_01, isal_deflate_hash_lvl0_01
diff --git a/igzip/igzip_rand_test.c b/igzip/igzip_rand_test.c
index 8e196f4..5f713ec 100644
--- a/igzip/igzip_rand_test.c
+++ b/igzip/igzip_rand_test.c
@@ -210,6 +210,29 @@ void create_rand_repeat_data(uint8_t * data, int size)
 	}
 }
 
+void create_rand_dict(uint8_t * dict, uint32_t dict_len, uint8_t * buf, uint32_t buf_len)
+{
+	uint32_t dict_chunk_size, buf_chunk_size;
+	while (dict_len > 0) {
+		dict_chunk_size = rand() % IGZIP_K;
+		dict_chunk_size = (dict_len >= dict_chunk_size) ? dict_chunk_size : dict_len;
+
+		buf_chunk_size = rand() % IGZIP_K;
+		buf_chunk_size = (buf_len >= buf_chunk_size) ? buf_chunk_size : buf_len;
+
+		if (rand() % 3 == 0 && buf_len >= dict_len)
+			memcpy(dict, buf, dict_chunk_size);
+		else
+			create_rand_repeat_data(dict, dict_chunk_size);
+
+		dict_len -= dict_chunk_size;
+		dict += dict_chunk_size;
+		buf_len -= buf_chunk_size;
+		buf += buf_chunk_size;
+	}
+
+}
+
 int get_rand_data_length(void)
 {
 	int max_mask =
@@ -435,7 +458,8 @@ int inflate_stateless_pass(uint8_t * compress_buf, uint64_t compress_len,
 }
 
 int inflate_multi_pass(uint8_t * compress_buf, uint64_t compress_len,
-		       uint8_t * uncompress_buf, uint32_t * uncompress_len, uint32_t gzip_flag)
+		       uint8_t * uncompress_buf, uint32_t * uncompress_len, uint32_t gzip_flag,
+		       uint8_t * dict, uint32_t dict_len)
 {
 	struct inflate_state *state = NULL;
 	int ret = 0;
@@ -452,6 +476,9 @@ int inflate_multi_pass(uint8_t * compress_buf, uint64_t compress_len,
 
 	isal_inflate_init(state);
 
+	if (dict != NULL)
+		isal_inflate_set_dict(state, dict, dict_len);
+
 	state->next_in = NULL;
 	state->next_out = NULL;
 	state->avail_in = 0;
@@ -583,7 +610,7 @@ int inflate_multi_pass(uint8_t * compress_buf, uint64_t compress_len,
 
 /* Inflate the  compressed data and check that the decompressed data agrees with the input data */
 int inflate_check(uint8_t * z_buf, int z_size, uint8_t * in_buf, int in_size,
-		  uint32_t gzip_flag)
+		  uint32_t gzip_flag, uint8_t * dict, uint32_t dict_len)
 {
 	/* Test inflate with reference inflate */
 
@@ -613,11 +640,13 @@ int inflate_check(uint8_t * z_buf, int z_size, uint8_t * in_buf, int in_size,
 		z_size -= zlib_hdr_bytes;
 	}
 
-	if (inflate_type == 0) {
+	if (inflate_type == 0 && dict == NULL) {
 		ret = inflate_stateless_pass(z_buf, z_size, test_buf, &test_size, gzip_flag);
 		inflate_type = 1;
 	} else {
-		ret = inflate_multi_pass(z_buf, z_size, test_buf, &test_size, gzip_flag);
+		ret =
+		    inflate_multi_pass(z_buf, z_size, test_buf, &test_size, gzip_flag, dict,
+				       dict_len);
 		inflate_type = 0;
 	}
 
@@ -796,7 +825,7 @@ void set_random_hufftable(struct isal_zstream *stream)
  * compression*/
 int compress_multi_pass(uint8_t * data, uint32_t data_size, uint8_t * compressed_buf,
 			uint32_t * compressed_size, uint32_t flush_type, uint32_t gzip_flag,
-			uint32_t level)
+			uint32_t level, uint8_t * dict, uint32_t dict_len)
 {
 	int ret = IGZIP_COMP_OK;
 	uint8_t *in_buf = NULL, *out_buf = NULL;
@@ -946,7 +975,7 @@ int compress_multi_pass(uint8_t * data, uint32_t data_size, uint8_t * compressed
 /* Compress the input data into the outbuffer in one call to isal_deflate */
 int compress_single_pass(uint8_t * data, uint32_t data_size, uint8_t * compressed_buf,
 			 uint32_t * compressed_size, uint32_t flush_type, uint32_t gzip_flag,
-			 uint32_t level)
+			 uint32_t level, uint8_t * dict, uint32_t dict_len)
 {
 	int ret = IGZIP_COMP_OK;
 	struct isal_zstream stream;
@@ -967,6 +996,9 @@ int compress_single_pass(uint8_t * data, uint32_t data_size, uint8_t * compresse
 	if (state->state != ZSTATE_NEW_HDR)
 		return COMPRESS_INCORRECT_STATE;
 
+	if (dict != NULL)
+		isal_deflate_set_dict(&stream, dict, dict_len);
+
 	stream.flush = flush_type;
 	stream.avail_in = data_size;
 	stream.next_in = data;
@@ -1153,7 +1185,9 @@ int compress_stateless_full_flush(uint8_t * data, uint32_t data_size, uint8_t *
 			break;
 
 		/* Verify that blocks are independent */
-		ret = inflate_check(out_buf, stream.next_out - out_buf, in_buf, in_size, 0);
+		ret =
+		    inflate_check(out_buf, stream.next_out - out_buf, in_buf, in_size, 0, NULL,
+				  0);
 
 		if (ret == INFLATE_INVALID_LOOK_BACK_DISTANCE) {
 			break;
@@ -1272,7 +1306,7 @@ int compress_full_flush(uint8_t * data, uint32_t data_size, uint8_t * compressed
 		if (state->state == ZSTATE_NEW_HDR || state->state == ZSTATE_END) {
 			ret =
 			    inflate_check(out_buf, stream.next_out - out_buf, in_buf, in_size,
-					  0);
+					  0, NULL, 0);
 
 			if (ret == INFLATE_INVALID_LOOK_BACK_DISTANCE)
 				break;
@@ -1425,7 +1459,7 @@ int test_compress_stateless(uint8_t * in_data, uint32_t in_size, uint32_t flush_
 	    compress_stateless(in_buf, in_size, z_buf, &z_size, flush_type, gzip_flag, level);
 
 	if (!ret)
-		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag);
+		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag, NULL, 0);
 
 #ifdef VERBOSE
 	if (ret) {
@@ -1473,7 +1507,7 @@ int test_compress_stateless(uint8_t * in_data, uint32_t in_size, uint32_t flush_
 	ret =
 	    compress_stateless(in_buf, in_size, z_buf, &z_size, flush_type, gzip_flag, level);
 	if (!ret)
-		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag);
+		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag, NULL, 0);
 #ifdef VERBOSE
 	if (ret) {
 		printf("Compressed array at level %d with gzip flag %d: ", level, gzip_flag);
@@ -1511,7 +1545,8 @@ int test_compress_stateless(uint8_t * in_data, uint32_t in_size, uint32_t flush_
 			print_error(overflow);
 			if (overflow == 0) {
 				overflow =
-				    inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag);
+				    inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag,
+						  NULL, 0);
 				printf("inflate ret = %d\n", overflow);
 				print_error(overflow);
 			}
@@ -1553,7 +1588,7 @@ int test_compress_stateless(uint8_t * in_data, uint32_t in_size, uint32_t flush_
 		ret = compress_stateless_full_flush(in_buf, in_size, z_buf, &z_size, level);
 
 		if (!ret)
-			ret = inflate_check(z_buf, z_size, in_buf, in_size, 0);
+			ret = inflate_check(z_buf, z_size, in_buf, in_size, 0, NULL, 0);
 		else if (ret == COMPRESS_LOOP_COUNT_OVERFLOW)
 			ret = 0;
 
@@ -1583,8 +1618,8 @@ int test_compress(uint8_t * in_buf, uint32_t in_size, uint32_t flush_type)
 {
 	int ret = IGZIP_COMP_OK, fin_ret = IGZIP_COMP_OK;
 	uint32_t overflow = 0, gzip_flag, level;
-	uint32_t z_size = 0, z_size_max = 0, z_compressed_size;
-	uint8_t *z_buf = NULL;
+	uint32_t z_size = 0, z_size_max = 0, z_compressed_size, dict_len = 0;
+	uint8_t *z_buf = NULL, *dict = NULL;
 
 	/* Test a non overflow case */
 	if (flush_type == NO_FLUSH)
@@ -1617,17 +1652,32 @@ int test_compress(uint8_t * in_buf, uint32_t in_size, uint32_t flush_type)
 	}
 	create_rand_repeat_data(z_buf, z_size);
 
+	if (rand() % 8 == 0) {
+		dict_len = (rand() % IGZIP_HIST_SIZE) + 1;
+		dict = malloc(dict_len);
+		if (dict == NULL) {
+			print_error(MALLOC_FAILED);
+			return MALLOC_FAILED;
+		}
+		create_rand_dict(dict, dict_len, z_buf, z_size);
+	}
+
 	ret = compress_single_pass(in_buf, in_size, z_buf, &z_size, flush_type,
-				   gzip_flag, level);
+				   gzip_flag, level, dict, dict_len);
 
 	if (!ret)
-		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag);
+		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag, dict, dict_len);
 
 	if (ret) {
 #ifdef VERBOSE
 		printf("Compressed array at level %d with gzip flag %d: ", level, gzip_flag);
 		print_uint8_t(z_buf, z_size);
 		printf("\n");
+		if (dict != NULL) {
+			printf("Using Dictionary: ");
+			print_uint8_t(dict, dict_len);
+			printf("\n");
+		}
 		printf("Data: ");
 		print_uint8_t(in_buf, in_size);
 #endif
@@ -1635,23 +1685,45 @@ int test_compress(uint8_t * in_buf, uint32_t in_size, uint32_t flush_type)
 		print_error(ret);
 	}
 
+	if (dict != NULL) {
+		free(dict);
+		dict = NULL;
+		dict_len = 0;
+	}
+
 	fin_ret |= ret;
 
 	z_compressed_size = z_size;
 	z_size = z_size_max;
 	create_rand_repeat_data(z_buf, z_size_max);
 
+	if (rand() % 8 == 0) {
+		dict_len = (rand() % IGZIP_HIST_SIZE) + 1;
+		dict = malloc(dict_len);
+		if (dict == NULL) {
+			print_error(MALLOC_FAILED);
+			return MALLOC_FAILED;
+		}
+		create_rand_dict(dict, dict_len, z_buf, z_size);
+	}
+
 	ret =
-	    compress_multi_pass(in_buf, in_size, z_buf, &z_size, flush_type, gzip_flag, level);
+	    compress_multi_pass(in_buf, in_size, z_buf, &z_size, flush_type, gzip_flag, level,
+				dict, dict_len);
 
 	if (!ret)
-		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag);
+		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag, dict, dict_len);
 
 	if (ret) {
 #ifdef VERBOSE
 		printf("Compressed array at level %d with gzip flag %d: ", level, gzip_flag);
 		print_uint8_t(z_buf, z_size);
 		printf("\n");
+		if (dict != NULL) {
+			printf("Using Dictionary: ");
+			print_uint8_t(dict, dict_len);
+			printf("\n");
+		}
 		printf("Data: ");
 		print_uint8_t(in_buf, in_size);
 #endif
@@ -1659,6 +1731,12 @@ int test_compress(uint8_t * in_buf, uint32_t in_size, uint32_t flush_type)
 		print_error(ret);
 	}
 
+	if (dict != NULL) {
+		free(dict);
+		dict = NULL;
+		dict_len = 0;
+	}
+
 	fin_ret |= ret;
 
 	ret = 0;
@@ -1671,11 +1749,13 @@ int test_compress(uint8_t * in_buf, uint32_t in_size, uint32_t flush_type)
 	create_rand_repeat_data(z_buf, z_size_max);
 
 	overflow = compress_single_pass(in_buf, in_size, z_buf, &z_size, flush_type,
-					gzip_flag, level);
+					gzip_flag, level, dict, dict_len);
 
 	if (overflow != COMPRESS_OUT_BUFFER_OVERFLOW) {
 		if (overflow == 0)
-			ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag);
+			ret =
+			    inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag, dict,
+					  dict_len);
 
 		/* Rarely single pass overflow will compresses data
 		 * better than the initial run. This is to stop that
@@ -1707,11 +1787,13 @@ int test_compress(uint8_t * in_buf, uint32_t in_size, uint32_t flush_type)
 
 		overflow =
 		    compress_multi_pass(in_buf, in_size, z_buf, &z_size, flush_type,
-					gzip_flag, level);
+					gzip_flag, level, dict, dict_len);
 
 		if (overflow != COMPRESS_OUT_BUFFER_OVERFLOW) {
 			if (overflow == 0)
-				ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag);
+				ret =
+				    inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag,
+						  dict, dict_len);
 
 			/* Rarely multi pass overflow will compresses data
 			 * better than the initial run. This is to stop that
@@ -1775,7 +1857,7 @@ int test_flush(uint8_t * in_buf, uint32_t in_size)
 
 	/* Test invalid flush */
 	ret = compress_single_pass(in_buf, in_size, z_buf, &z_size, flush_type,
-				   gzip_flag, level);
+				   gzip_flag, level, NULL, 0);
 
 	if (ret == COMPRESS_GENERAL_ERROR)
 		ret = 0;
@@ -1793,7 +1875,7 @@ int test_flush(uint8_t * in_buf, uint32_t in_size)
 	ret = compress_swap_flush(in_buf, in_size, z_buf, &z_size, rand() % 3, gzip_flag);
 
 	if (!ret)
-		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag);
+		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag, NULL, 0);
 
 	if (ret) {
 #ifdef VERBOSE
@@ -1844,7 +1926,7 @@ int test_full_flush(uint8_t * in_buf, uint32_t in_size)
 	ret = compress_full_flush(in_buf, in_size, z_buf, &z_size, gzip_flag, level);
 
 	if (!ret)
-		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag);
+		ret = inflate_check(z_buf, z_size, in_buf, in_size, gzip_flag, NULL, 0);
 
 	if (ret) {
 #ifdef VERBOSE
@@ -1887,7 +1969,8 @@ int test_inflate(struct vect_result *in_vector)
 		ret = IGZIP_COMP_OK;
 
 	if (!ret) {
-		ret = inflate_multi_pass(compress_buf, compress_len, out_buf, &out_size, 0);
+		ret = inflate_multi_pass(compress_buf, compress_len, out_buf, &out_size,
+					 0, NULL, 0);
 
 		if (ret == INFLATE_LEFTOVER_INPUT)
 			ret = ISAL_DECOMP_OK;
diff --git a/igzip/inflate_data_structs.asm b/igzip/inflate_data_structs.asm
index 3d4d24d..8742a31 100644
--- a/igzip/inflate_data_structs.asm
+++ b/igzip/inflate_data_structs.asm
@@ -89,6 +89,7 @@ FIELD	_read_in_length,4,	4
 FIELD	_lit_huff_code,	_inflate_huff_code_large_size,	_inflate_huff_code_large_align
 FIELD	_dist_huff_code,_inflate_huff_code_small_size,	_inflate_huff_code_small_align
 FIELD	_block_state,	4,	4
+FIELD	_dict_length,	4,	4
 FIELD	_bfinal,	4,	4
 FIELD	_crc_flag,	4,	4
 FIELD	_crc,		4,	4
diff --git a/include/igzip_lib.h b/include/igzip_lib.h
index f116810..a7098db 100644
--- a/include/igzip_lib.h
+++ b/include/igzip_lib.h
@@ -156,7 +156,7 @@ enum {IGZIP_LIT_TABLE_SIZE = ISAL_DEF_LIT_SYMBOLS};
 #define STATELESS_OVERFLOW -1
 #define ISAL_INVALID_OPERATION -9
 #define ISAL_INVALID_LEVEL -4	/* Invalid Compression level set */
-
+#define ISAL_INVALID_STATE -3
 /**
  *  @enum isal_zstate_state
  *  @brief Compression State please note ZSTATE_TRL only applies for GZIP compression
@@ -264,6 +264,10 @@ struct isal_mod_hist {
 #define ISAL_DEF_LVL1_EXTRA_LARGE (ISAL_DEF_LVL1_REQ + ISAL_DEF_LVL1_TOKEN_SIZE * 128 * IGZIP_K)
 #define ISAL_DEF_LVL1_DEFAULT ISAL_DEF_LVL1_LARGE
 
+#define IGZIP_NO_HIST 0
+#define IGZIP_HIST 1
+#define IGZIP_DICT_HIST 2
+
 /** @brief Holds Bit Buffer information*/
 struct BitBuf2 {
 	uint64_t m_bits;	//!< bits in the bit buffer
@@ -410,6 +414,7 @@ struct inflate_state {
 	struct inflate_huff_code_large lit_huff_code;	//!< Structure for decoding lit/len symbols
 	struct inflate_huff_code_small dist_huff_code;	//!< Structure for decoding dist symbols
 	enum isal_block_state block_state;	//!< Current decompression state
+	uint32_t dict_length;	//!< Length of dictionary used
 	uint32_t bfinal;	//!< Flag identifying final block
 	uint32_t crc_flag;	//!< Flag identifying whether to track of crc
 	uint32_t crc;		//!< Contains crc of output if crc_flag is set
@@ -506,6 +511,22 @@ int isal_deflate_set_hufftables(struct isal_zstream *stream,
 void isal_deflate_stateless_init(struct isal_zstream *stream);
 
 
+/**
+ * @brief Set compression dictionary to use
+ *
+ * This function is to be called after isal_deflate_init, or after completing a
+ * SYNC_FLUSH or FULL_FLUSH and before the next call do isal_deflate. If the
+ * dictionary is longer than IGZIP_HIST_SIZE, only the last IGZIP_HIST_SIZE
+ * bytes will be used.
+ *
+ * @param stream Structure holding state information on the compression streams.
+ * @param dict: Array containing dictionary to use.
+ * @param dict_len: Lenth of dict.
+ * @returns COMP_OK,
+ *          ISAL_INVALID_STATE (dictionary could not be set)
+ */
+int isal_deflate_set_dict(struct isal_zstream *stream, uint8_t *dict, uint32_t dict_len);
+
 /**
  * @brief Fast data (deflate) compression for storage applications.
  *
@@ -546,6 +567,9 @@ void isal_deflate_stateless_init(struct isal_zstream *stream);
  * not include previous blocks so new blocks are fully independent. Switching
  * between flush types is supported.
  *
+ * If a compression dictionary is required, the dictionary can be set calling
+ * isal_deflate_set_dictionary before calling isal_deflate.
+ *
  * If the gzip_flag is set to IGZIP_GZIP, a generic gzip header and the gzip
  * trailer are written around the deflate compressed data. If gzip_flag is set
  * to IGZIP_GZIP_NO_HDR, then only the gzip trailer is written.
@@ -598,6 +622,21 @@ int isal_deflate_stateless(struct isal_zstream *stream);
  */
 void isal_inflate_init(struct inflate_state *state);
 
+/**
+ * @brief Set decompression dictionary to use
+ *
+ * This function is to be called after isal_inflate_init. If the dictionary is
+ * longer than IGZIP_HIST_SIZE, only the last IGZIP_HIST_SIZE bytes will be
+ * used.
+ *
+ * @param state: Structure holding state information on the decompression stream.
+ * @param dict: Array containing dictionary to use.
+ * @param dict_len: Lenth of dict.
+ * @returns COMP_OK,
+ *          ISAL_INVALID_STATE (dictionary could not be set)
+ */
+int isal_inflate_set_dict(struct inflate_state *state, uint8_t *dict, uint32_t dict_len);
+
 /**
  * @brief Fast data (deflate) decompression for storage applications.
  *
@@ -617,6 +656,9 @@ void isal_inflate_init(struct inflate_state *state);
  * in state->crc. Alternatively, if the crc_flag is set to ISAL_ZLIB_NO_HDR the
  * adler32 of the output is stored in state->crc.
  *
+ * If a dictionary is required, a call to isal_inflate_set_dict will set the
+ * dictionary.
+ *
  * @param  state Structure holding state information on the compression streams.
  * @return ISAL_DECOMP_OK (if everything is ok),
  *         ISAL_END_INPUT (if all input was decompressed),
@@ -625,6 +667,7 @@ void isal_inflate_init(struct inflate_state *state);
  *         ISAL_INVALID_SYMBOL,
  *         ISAL_INVALID_LOOKBACK.
  */
+
 int isal_inflate(struct inflate_state *state);
 
 /**