EncodedSecurityDesc (FIX tag 351)

dataFIX 4.4FIX 4.2FIX 5.0 SP2

EncodedSecurityDesc (tag 351) is a data field defined in FIX 4.4, FIX 4.2 and FIX 5.0 SP2. It appears in 59 message types, always optionally. It is length-prefixed — tag 350 carries the byte count, so the value may contain the SOH separator without breaking the message.

At a glance

Tag: 351
Name: EncodedSecurityDesc
Datatype: data
Dialects: FIX 4.4, FIX 4.2 and FIX 5.0 SP2
Messages: 59
Length field: tag 350

What the specification says

FIX 4.4

Encoded (non-ASCII characters) representation of the SecurityDesc (07) field in the encoded format specified via the MessageEncoding (347) field. If used, the ASCII (English) representation should also be specified in the SecurityDesc field.

FIX 4.2

Encoded (non-ASCII characters) representation of the SecurityDesc field in the encoded format specified via the MessageEncoding field. If used, the ASCII (English) representation should also be specified in the SecurityDesc field.

FIX 5.0 SP2

Encoded (non-ASCII characters) representation of the SecurityDesc (107) field in the encoded format specified via the MessageEncoding (347) field. If used, the ASCII (English) representation should also be specified in the SecurityDesc field.

Descriptions are quoted from the FIX Orchestra sources under the Apache 2.0 licence.

A real message using tag 351

NewOrderSingle · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	129
35	MsgType	D	Order – Single
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
11	ClOrdID	ORD-10042
350	EncodedSecurityDescLen	7
351	EncodedSecurityDesc	EXAMPLE
54	Side	1	Buy
60	TransactTime	20240101-12:00:00.000
40	OrdType	1	Market
10	CheckSum	233

Edit and decode it yourself

Shown with | separators for readability. On the wire FIX uses SOH (0x01), an invisible control byte — and because BodyLength and CheckSum are computed over the actual bytes, the two forms have different checksums. Both are valid and both decode here.

Open in the full decoder →

Generated from the FIX 4.4 dictionary and verified at build time: it parses and validates with no issues. Open the decoder to try your own message.

Where tag 351 appears

Requiredness is a property of the message, not of the field: the same tag can be optional in one message and conditionally required in another.

Message	MsgType	FIX 4.4	FIX 4.2	FIX 5.0 SP2	Where in the message
AdjustedPositionReport	BL	—	—	Optional	inside InstrmtGrp › Instrument
Advertisement	7	Conditional	Optional	Optional	inside the Instrument component
AllocationInstruction	J	Conditional	Optional	Optional	inside the Instrument component
AllocationInstructionAlert	BM	—	—	Optional	inside the Instrument component
AllocationReport	AS	Conditional	—	Optional	inside the Instrument component
AssignmentReport	AW	Conditional	—	Optional	inside the Instrument component
CollateralAssignment	AY	Conditional	—	Optional	inside the Instrument component
CollateralInquiry	BB	Conditional	—	Optional	inside the Instrument component
CollateralInquiryAck	BG	Conditional	—	Optional	inside the Instrument component
CollateralReport	BA	Conditional	—	Optional	inside the Instrument component
CollateralRequest	AX	Conditional	—	Optional	inside the Instrument component
CollateralResponse	AZ	Conditional	—	Optional	inside the Instrument component
Confirmation	AK	Conditional	—	Optional	inside the Instrument component
ContraryIntentionReport	BO	—	—	Optional	inside the Instrument component
CrossOrderCancelReplaceRequest	t	Conditional	—	Optional	inside the Instrument component
CrossOrderCancelRequest	u	Conditional	—	Optional	inside the Instrument component
DerivativeSecurityList	AA	Conditional	—	Optional	inside RelSymDerivSecGrp › Instrument
DerivativeSecurityListUpdateReport	BR	—	—	Optional	inside RelSymDerivSecUpdGrp › Instrument
DontKnowTrade	Q	Conditional	Optional	Optional	inside the Instrument component
Email	C	Conditional	Optional	Optional	inside InstrmtGrp › Instrument
ExecutionAcknowledgement	BN	—	—	Optional	inside the Instrument component
ExecutionReport	8	Conditional	Optional	Optional	inside the Instrument component
IOI	6	Conditional	Optional	Optional	inside the Instrument component
ListStrikePrice	m	Conditional	Optional	Optional	inside InstrmtStrkPxGrp › Instrument
MarketDataIncrementalRefresh	X	Conditional	Optional	Optional	inside MDIncGrp › Instrument
MarketDataRequest	V	Conditional	Optional	Optional	inside InstrmtMDReqGrp › Instrument
MarketDataSnapshotFullRefresh	W	Conditional	Optional	Optional	inside the Instrument component
MassQuote	i	Conditional	Optional	Optional	inside QuotSetGrp › QuotEntryGrp › Instrument
MassQuoteAcknowledgement	b	Conditional	Optional	Optional	inside QuotSetAckGrp › QuotEntryAckGrp › Instrument
MultilegOrderCancelReplace	AC	Conditional	—	Optional	inside the Instrument component
NewOrderCross	s	Conditional	—	Optional	inside the Instrument component
NewOrderList	E	Conditional	Optional	Optional	inside ListOrdGrp › Instrument
NewOrderMultileg	AB	Conditional	—	Optional	inside the Instrument component
NewOrderSingle	D	Conditional	Optional	Optional	inside the Instrument component
News	B	Conditional	Optional	Optional	inside InstrmtGrp › Instrument
OrderCancelReplaceRequest	G	Conditional	Optional	Optional	inside the Instrument component
OrderCancelRequest	F	Conditional	Optional	Optional	inside the Instrument component
OrderMassActionReport	BZ	—	—	Optional	inside the Instrument component
OrderMassActionRequest	CA	—	—	Optional	inside the Instrument component
OrderMassCancelReport	r	Conditional	—	Optional	inside the Instrument component
OrderMassCancelRequest	q	Conditional	—	Optional	inside the Instrument component
OrderMassStatusRequest	AF	Conditional	—	Optional	inside the Instrument component
OrderStatusRequest	H	Conditional	Optional	Optional	inside the Instrument component
PositionMaintenanceReport	AM	Conditional	—	Optional	inside the Instrument component
PositionMaintenanceRequest	AL	Conditional	—	Optional	inside the Instrument component
PositionReport	AP	Conditional	—	Optional	inside the Instrument component
Quote	S	Conditional	Optional	Optional	inside the Instrument component
QuoteCancel	Z	Conditional	Optional	Optional	inside QuotCxlEntriesGrp › Instrument
QuoteRequest	R	Conditional	Optional	Optional	inside QuotReqGrp › Instrument
QuoteRequestReject	AG	Conditional	—	Optional	inside QuotReqRjctGrp › Instrument
QuoteResponse	AJ	Conditional	—	Optional	inside the Instrument component
QuoteStatusReport	AI	Conditional	—	Optional	inside the Instrument component
QuoteStatusRequest	a	Conditional	Optional	Optional	inside the Instrument component
RFQRequest	AH	Conditional	—	Optional	inside RFQReqGrp › Instrument
RequestForPositions	AN	Conditional	—	Optional	inside the Instrument component
RequestForPositionsAck	AO	Conditional	—	Optional	inside the Instrument component
SecurityDefinition	d	Conditional	Optional	Optional	inside the Instrument component
SecurityDefinitionRequest	c	Conditional	Optional	Optional	inside the Instrument component
SecurityDefinitionUpdateReport	BP	—	—	Optional	inside the Instrument component
SecurityList	y	Conditional	—	Optional	inside SecListGrp › Instrument
SecurityListRequest	x	Conditional	—	Optional	inside the Instrument component
SecurityListUpdateReport	BK	—	—	Optional	inside SecLstUpdRelSymGrp › Instrument
SecurityStatus	f	Conditional	Optional	Optional	inside the Instrument component
SecurityStatusRequest	e	Conditional	Optional	Optional	inside the Instrument component
SettlementObligationReport	BQ	—	—	Optional	inside SettlObligationInstructions › Instrument
StreamAssignmentReport	CD	—	—	Optional	inside StrmAsgnRptGrp › StrmAsgnRptInstrmtGrp › Instrument
StreamAssignmentRequest	CC	—	—	Optional	inside StrmAsgnReqGrp › StrmAsgnReqInstrmtGrp › Instrument
TradeCaptureReport	AE	Conditional	—	Optional	inside the Instrument component
TradeCaptureReportAck	AR	Conditional	—	Optional	inside the Instrument component
TradeCaptureReportRequest	AD	Conditional	—	Optional	inside the Instrument component
TradeCaptureReportRequestAck	AQ	Conditional	—	Optional	inside the Instrument component
TradingSessionStatus	h	—	—	Optional	inside the Instrument component

Wire format

Raw bytes, length-prefixed by a partner field. The value may legally contain the SOH separator, which is why the length matters. @boarteam/fix reads the partner length field first and takes exactly that many bytes, so an embedded separator does not truncate the value.

Read tag 351 in TypeScript

decode.tsts

import { createFixEngine } from "@boarteam/fix";import { dictionary } from "@boarteam/fix-dict-fix44";const fix = createFixEngine(dictionary);const { message, issues } = fix.parse(raw);// Length-prefixed: tag 350 carries the byte count, so the// value may contain the SOH separator without breaking the message.const length = message.fields[350]?.value;const encodedSecurityDesc = message.fields[351]?.raw;

Decode this in your own code

The same engine that produced the decoded example above is an Apache-2.0 npm package with zero runtime dependencies. It runs in Node and in the browser, and parse() returns problems as data instead of throwing.

npm i @boarteam/fix @boarteam/fix-dict-fix44

Try the decoder Source on GitHub