diff --git a/lib/lfrfid/protocols/lfrfid_protocols.c b/lib/lfrfid/protocols/lfrfid_protocols.c
index 6d42cf31e..30ba24e6e 100644
--- a/lib/lfrfid/protocols/lfrfid_protocols.c
+++ b/lib/lfrfid/protocols/lfrfid_protocols.c
@@ -8,6 +8,7 @@
 #include "protocol_fdx_b.h"
 #include "protocol_hid_generic.h"
 #include "protocol_hid_ex_generic.h"
+#include "protocol_viking.h"
 #include "protocol_jablotron.h"
 #include "protocol_paradox.h"
 #include "protocol_pac_stanley.h"
@@ -22,6 +23,7 @@ const ProtocolBase* lfrfid_protocols[] = {
     [LFRFIDProtocolFDXB] = &protocol_fdx_b,
     [LFRFIDProtocolHidGeneric] = &protocol_hid_generic,
     [LFRFIDProtocolHidExGeneric] = &protocol_hid_ex_generic,
+    [LFRFIDProtocolViking] = &protocol_viking,
     [LFRFIDProtocolJablotron] = &protocol_jablotron,
     [LFRFIDProtocolParadox] = &protocol_paradox,
     [LFRFIDProtocolPACStanley] = &protocol_pac_stanley,
diff --git a/lib/lfrfid/protocols/lfrfid_protocols.h b/lib/lfrfid/protocols/lfrfid_protocols.h
index 42113af1e..710b6e57b 100644
--- a/lib/lfrfid/protocols/lfrfid_protocols.h
+++ b/lib/lfrfid/protocols/lfrfid_protocols.h
@@ -17,6 +17,7 @@ typedef enum {
     LFRFIDProtocolFDXB,
     LFRFIDProtocolHidGeneric,
     LFRFIDProtocolHidExGeneric,
+    LFRFIDProtocolViking,
     LFRFIDProtocolJablotron,
     LFRFIDProtocolParadox,
     LFRFIDProtocolPACStanley,
diff --git a/lib/lfrfid/protocols/protocol_viking.c b/lib/lfrfid/protocols/protocol_viking.c
new file mode 100644
index 000000000..7fd72bd93
--- /dev/null
+++ b/lib/lfrfid/protocols/protocol_viking.c
@@ -0,0 +1,201 @@
+#include <furi.h>
+#include <toolbox/protocols/protocol.h>
+#include <toolbox/manchester_decoder.h>
+#include <lfrfid/tools/bit_lib.h>
+#include "lfrfid_protocols.h"
+
+#define VIKING_CLOCK_PER_BIT (32)
+
+#define VIKING_ENCODED_BIT_SIZE (64)
+#define VIKING_ENCODED_BYTE_SIZE (((VIKING_ENCODED_BIT_SIZE) / 8))
+#define VIKING_PREAMBLE_BIT_SIZE (24)
+#define VIKING_PREAMBLE_BYTE_SIZE (3)
+#define VIKING_ENCODED_BYTE_FULL_SIZE (VIKING_ENCODED_BYTE_SIZE + VIKING_PREAMBLE_BYTE_SIZE)
+#define VIKING_DECODED_DATA_SIZE 4
+
+#define VIKING_READ_SHORT_TIME (128)
+#define VIKING_READ_LONG_TIME (256)
+#define VIKING_READ_JITTER_TIME (60)
+
+#define VIKING_READ_SHORT_TIME_LOW (VIKING_READ_SHORT_TIME - VIKING_READ_JITTER_TIME)
+#define VIKING_READ_SHORT_TIME_HIGH (VIKING_READ_SHORT_TIME + VIKING_READ_JITTER_TIME)
+#define VIKING_READ_LONG_TIME_LOW (VIKING_READ_LONG_TIME - VIKING_READ_JITTER_TIME)
+#define VIKING_READ_LONG_TIME_HIGH (VIKING_READ_LONG_TIME + VIKING_READ_JITTER_TIME)
+
+typedef struct {
+    uint8_t data[VIKING_DECODED_DATA_SIZE];
+    uint8_t encoded_data[VIKING_ENCODED_BYTE_FULL_SIZE];
+
+    uint8_t encoded_data_index;
+    bool encoded_polarity;
+
+    ManchesterState decoder_manchester_state;
+} ProtocolViking;
+
+ProtocolViking* protocol_viking_alloc(void) {
+    ProtocolViking* proto = malloc(sizeof(ProtocolViking));
+    return (void*)proto;
+};
+
+void protocol_viking_free(ProtocolViking* protocol) {
+    free(protocol);
+};
+
+uint8_t* protocol_viking_get_data(ProtocolViking* protocol) {
+    return protocol->data;
+};
+
+static void protocol_viking_decode(ProtocolViking* protocol) {
+    // Copy Card ID
+    bit_lib_copy_bits(protocol->data, 0, 32, protocol->encoded_data, 24);
+}
+
+static bool protocol_viking_can_be_decoded(ProtocolViking* protocol) {
+    // check 24 bits preamble
+    if(bit_lib_get_bits_16(protocol->encoded_data, 0, 16) != 0b1111001000000000) return false;
+    if(bit_lib_get_bits(protocol->encoded_data, 16, 8) != 0b00000000) return false;
+
+    // check next 24 bits preamble
+    if(bit_lib_get_bits_16(protocol->encoded_data, 64, 16) != 0b1111001000000000) return false;
+    if(bit_lib_get_bits(protocol->encoded_data, 80, 8) != 0b00000000) return false;
+
+    // Checksum
+    uint32_t checksum = bit_lib_get_bits(protocol->encoded_data, 0, 8) ^
+                        bit_lib_get_bits(protocol->encoded_data, 8, 8) ^
+                        bit_lib_get_bits(protocol->encoded_data, 16, 8) ^
+                        bit_lib_get_bits(protocol->encoded_data, 24, 8) ^
+                        bit_lib_get_bits(protocol->encoded_data, 32, 8) ^
+                        bit_lib_get_bits(protocol->encoded_data, 40, 8) ^
+                        bit_lib_get_bits(protocol->encoded_data, 48, 8) ^
+                        bit_lib_get_bits(protocol->encoded_data, 56, 8) ^ 0xA8;
+    if(checksum != 0) return false;
+
+    return true;
+}
+
+void protocol_viking_decoder_start(ProtocolViking* protocol) {
+    memset(protocol->encoded_data, 0, VIKING_ENCODED_BYTE_FULL_SIZE);
+    manchester_advance(
+        protocol->decoder_manchester_state,
+        ManchesterEventReset,
+        &protocol->decoder_manchester_state,
+        NULL);
+};
+
+bool protocol_viking_decoder_feed(ProtocolViking* protocol, bool level, uint32_t duration) {
+    bool result = false;
+
+    ManchesterEvent event = ManchesterEventReset;
+
+    if(duration > VIKING_READ_SHORT_TIME_LOW && duration < VIKING_READ_SHORT_TIME_HIGH) {
+        if(!level) {
+            event = ManchesterEventShortHigh;
+        } else {
+            event = ManchesterEventShortLow;
+        }
+    } else if(duration > VIKING_READ_LONG_TIME_LOW && duration < VIKING_READ_LONG_TIME_HIGH) {
+        if(!level) {
+            event = ManchesterEventLongHigh;
+        } else {
+            event = ManchesterEventLongLow;
+        }
+    }
+
+    if(event != ManchesterEventReset) {
+        bool data;
+        bool data_ok = manchester_advance(
+            protocol->decoder_manchester_state, event, &protocol->decoder_manchester_state, &data);
+
+        if(data_ok) {
+            bit_lib_push_bit(protocol->encoded_data, VIKING_ENCODED_BYTE_FULL_SIZE, data);
+
+            if(protocol_viking_can_be_decoded(protocol)) {
+                protocol_viking_decode(protocol);
+                result = true;
+            }
+        }
+    }
+
+    return result;
+};
+
+bool protocol_viking_encoder_start(ProtocolViking* protocol) {
+    // Preamble
+    bit_lib_set_bits(protocol->encoded_data, 0, 0b11110010, 8);
+    bit_lib_set_bits(protocol->encoded_data, 8, 0b00000000, 8);
+    bit_lib_set_bits(protocol->encoded_data, 16, 0b00000000, 8);
+
+    // Card Id
+    bit_lib_copy_bits(protocol->encoded_data, 24, 32, protocol->data, 0);
+
+    // Checksum
+    uint32_t id = bit_lib_get_bits_32(protocol->data, 0, 32);
+    uint8_t checksum = ((id >> 24) & 0xFF) ^ ((id >> 16) & 0xFF) ^ ((id >> 8) & 0xFF) ^
+                       (id & 0xFF) ^ 0xF2 ^ 0xA8;
+    bit_lib_set_bits(protocol->encoded_data, 56, checksum, 8);
+
+    return true;
+};
+
+LevelDuration protocol_viking_encoder_yield(ProtocolViking* protocol) {
+    bool level = bit_lib_get_bit(protocol->encoded_data, protocol->encoded_data_index);
+    uint32_t duration = VIKING_CLOCK_PER_BIT / 2;
+
+    if(protocol->encoded_polarity) {
+        protocol->encoded_polarity = false;
+    } else {
+        level = !level;
+
+        protocol->encoded_polarity = true;
+        bit_lib_increment_index(protocol->encoded_data_index, VIKING_ENCODED_BIT_SIZE);
+    }
+
+    return level_duration_make(level, duration);
+};
+
+bool protocol_viking_write_data(ProtocolViking* protocol, void* data) {
+    LFRFIDWriteRequest* request = (LFRFIDWriteRequest*)data;
+    bool result = false;
+
+    protocol_viking_encoder_start(protocol);
+
+    if(request->write_type == LFRFIDWriteTypeT5577) {
+        request->t5577.block[0] =
+            (LFRFID_T5577_MODULATION_MANCHESTER | LFRFID_T5577_BITRATE_RF_32 |
+             (2 << LFRFID_T5577_MAXBLOCK_SHIFT));
+        request->t5577.block[1] = bit_lib_get_bits_32(protocol->encoded_data, 0, 32);
+        request->t5577.block[2] = bit_lib_get_bits_32(protocol->encoded_data, 32, 32);
+        request->t5577.blocks_to_write = 3;
+        result = true;
+    }
+    return result;
+};
+
+void protocol_viking_render_data(ProtocolViking* protocol, string_t result) {
+    uint32_t id = bit_lib_get_bits_32(protocol->data, 0, 32);
+    string_printf(result, "ID: %08lx\r\n", id);
+};
+
+const ProtocolBase protocol_viking = {
+    .name = "Viking",
+    .manufacturer = "Viking",
+    .data_size = VIKING_DECODED_DATA_SIZE,
+    .features = LFRFIDFeatureASK,
+    .validate_count = 3,
+    .alloc = (ProtocolAlloc)protocol_viking_alloc,
+    .free = (ProtocolFree)protocol_viking_free,
+    .get_data = (ProtocolGetData)protocol_viking_get_data,
+    .decoder =
+        {
+            .start = (ProtocolDecoderStart)protocol_viking_decoder_start,
+            .feed = (ProtocolDecoderFeed)protocol_viking_decoder_feed,
+        },
+    .encoder =
+        {
+            .start = (ProtocolEncoderStart)protocol_viking_encoder_start,
+            .yield = (ProtocolEncoderYield)protocol_viking_encoder_yield,
+        },
+    .render_data = (ProtocolRenderData)protocol_viking_render_data,
+    .render_brief_data = (ProtocolRenderData)protocol_viking_render_data,
+    .write_data = (ProtocolWriteData)protocol_viking_write_data,
+};
\ No newline at end of file
diff --git a/lib/lfrfid/protocols/protocol_viking.h b/lib/lfrfid/protocols/protocol_viking.h
new file mode 100644
index 000000000..3286e03a7
--- /dev/null
+++ b/lib/lfrfid/protocols/protocol_viking.h
@@ -0,0 +1,4 @@
+#pragma once
+#include <toolbox/protocols/protocol.h>
+
+extern const ProtocolBase protocol_viking;