Computed Radiography ImageCIOD
Nuclear Medicine ImageCIOD
Ultrasound ImageCIOD
Ultrasound Multi-frame ImageCIOD
Secondary Capture ImageCIOD
Multi-frame Single Bit Secondary Capture ImageCIOD
Multi-frame Grayscale Byte Secondary Capture ImageCIOD
Multi-frame Grayscale Word Secondary Capture ImageCIOD
Multi-frame True Color Secondary Capture ImageCIOD
X-Ray Angiographic ImageCIOD
X-Ray Radiofluoroscopic ImageCIOD
RT Structure SetCIOD
Positron Emission Tomography ImageCIOD
Digital X-Ray ImageCIOD
Digital Mammography X-Ray ImageCIOD
Digital Intra-Oral X-Ray ImageCIOD
RT Beams Treatment RecordCIOD
RT Brachy Treatment RecordCIOD
RT Treatment Summary RecordCIOD
VL Endoscopic ImageCIOD
VL Microscopic ImageCIOD
VL Slide-Coordinates Microscopic ImageCIOD
VL Photographic ImageCIOD
Video Endoscopic ImageCIOD
Video Microscopic ImageCIOD
Video Photographic ImageCIOD
VL Whole Slide Microscopy ImageCIOD
Real-Time Video Endoscopic ImageCIOD
Real-Time Video Photographic ImageCIOD
Dermoscopic Photography ImageCIOD
Grayscale Softcopy Presentation StateCIOD
Color Softcopy Presentation StateCIOD
Pseudo-Color Softcopy Presentation StateCIOD
Blending Softcopy Presentation StateCIOD
Basic Structured DisplayCIOD
XA/XRF Grayscale Softcopy Presentation StateCIOD
Advanced Blending Presentation StateCIOD
Variable Modality LUT Softcopy Presentation StateCIOD
Basic Voice Audio WaveformCIOD
PatientMModule - Patient
Clinical Trial SubjectUModule - Patient
General StudyMModule - Study
Patient StudyUModule - Study
Clinical Trial StudyUModule - Study
General SeriesMModule - Series
Clinical Trial SeriesUModule - Series
SynchronizationUModule - Frame of Reference
General EquipmentMModule - Equipment
Waveform IdentificationMModule - Waveform
WaveformMModule - Waveform
Acquisition ContextMModule - Waveform
Waveform AnnotationUModule - Waveform
SOP CommonMModule - Waveform
(0008,0005) Specific Character Set1CCode String
(0008,0012) Instance Creation Date3Date
(0008,0013) Instance Creation Time3Time
(0008,0014) Instance Creator UID3Unique Identifier
(0008,0015) Instance Coercion DateTime3Date Time
(0008,0016) SOP Class UID1Unique Identifier
(0008,0018) SOP Instance UID1Unique Identifier
(0008,001A) Related General SOP Class UID3Unique Identifier
(0008,001B) Original Specialized SOP Class UID3Unique Identifier
(0008,001C) Synthetic Data3Code String
(0008,0053) Query/Retrieve View1CCode String
(0008,0110) Coding Scheme Identification Sequence3Sequence
(0008,0123) Context Group Identification Sequence3Sequence
(0008,0124) Mapping Resource Identification Sequence3Sequence
(0008,0201) Timezone Offset From UTC3Short String
(0008,0300) Private Data Element Characteristics Sequence3Sequence
(0018,9004) Content Qualification3Code String
(0018,990C) Referenced Defined Protocol Sequence1CSequence
(0018,990D) Referenced Performed Protocol Sequence1CSequence
(0018,A001) Contributing Equipment Sequence3Sequence
(0020,0013) Instance Number3Integer String
(0020,9172) Conversion Source Attributes Sequence1CSequence
(0028,0303) Longitudinal Temporal Information Modified3Code String
(0040,A390) HL7 Structured Document Reference Sequence1CSequence
(0100,0410) SOP Instance Status3Code String
(0100,0420) SOP Authorization DateTime3Date Time
(0100,0424) SOP Authorization Comment3Long Text
(0100,0426) Authorization Equipment Certification Number3Long String
(0400,0500) Encrypted Attributes Sequence1CSequence
(0400,0561) Original Attributes Sequence3Sequence
(0400,0600) Instance Origin Status3Code String
(2200,0005) Barcode Value3Long Text
(4FFE,0001) MAC Parameters Sequence3Sequence
(FFFA,FFFA) Digital Signatures Sequence3Sequence
(0400,0005) MAC ID Number1Unsigned Short
(0400,0100) Digital Signature UID1Unique Identifier
(0400,0105) Digital Signature DateTime1Date Time
(0400,0110) Certificate Type1Code String
(0400,0115) Certificate of Signer1Other Byte String
(0400,0120) Signature1Other Byte String
(0400,0305) Certified Timestamp Type1CCode String
(0400,0310) Certified Timestamp3Other Byte String
(0400,0401) Digital Signature Purpose Code Sequence3Sequence
Ambulatory ECGCIOD
Hemodynamic WaveformCIOD
Basic Cardiac Electrophysiology WaveformCIOD
Arterial Pulse WaveformCIOD
Respiratory WaveformCIOD
General Audio WaveformCIOD
Real-Time Audio WaveformCIOD
Routine Scalp ElectroencephalogramCIOD
Sleep ElectroencephalogramCIOD
Multi-channel Respiratory WaveformCIOD
Body Position WaveformCIOD
General 32-bit ECGCIOD
Basic Text SRCIOD
Enhanced SRCIOD
Comprehensive SRCIOD
Key Object Selection DocumentCIOD
Mammography CAD SRCIOD
Procedure LogCIOD
X-Ray Radiation Dose SRCIOD
Spectacle Prescription ReportCIOD
Macular Grid Thickness and Volume ReportCIOD
Implantation Plan SR DocumentCIOD
Comprehensive 3D SRCIOD
Radiopharmaceutical Radiation Dose SRCIOD
Extensible SRCIOD
Acquisition Context SRCIOD
Simplified Adult Echo SRCIOD
Patient Radiation Dose SRCIOD
Planned Imaging Agent Administration SRCIOD
Performed Imaging Agent Administration SRCIOD
Rendition Selection DocumentCIOD
Enhanced X-Ray Radiation Dose SRCIOD
Enhanced MR ImageCIOD
MR SpectroscopyCIOD
Enhanced MR Color ImageCIOD
Raw DataCIOD
Enhanced CT ImageCIOD
Spatial RegistrationCIOD
Deformable Spatial RegistrationCIOD
Spatial FiducialsCIOD
Ophthalmic Photography 8 Bit ImageCIOD
Ophthalmic Photography 16 Bit ImageCIOD
Stereometric RelationshipCIOD
Hanging ProtocolCIOD
Encapsulated PDFCIOD
Encapsulated CDACIOD
Real World Value MappingCIOD
Enhanced XA ImageCIOD
Enhanced XRF ImageCIOD
RT Ion Beams Treatment RecordCIOD
Ophthalmic Tomography ImageCIOD
X-Ray 3D Angiographic ImageCIOD
X-Ray 3D Craniofacial ImageCIOD
Breast Tomosynthesis ImageCIOD
Enhanced PET ImageCIOD
Surface SegmentationCIOD
Color PaletteCIOD
Enhanced US VolumeCIOD
Lensometry MeasurementsCIOD
Autorefraction MeasurementsCIOD
Keratometry MeasurementsCIOD
Subjective Refraction MeasurementsCIOD
Visual Acuity MeasurementsCIOD
Ophthalmic Axial MeasurementsCIOD
Intraocular Lens CalculationsCIOD
Generic Implant TemplateCIOD
Implant Assembly TemplateCIOD
Implant Template GroupCIOD
RT Beams Delivery InstructionCIOD
Ophthalmic Visual Field Static Perimetry MeasurementsCIOD
Intravascular Optical Coherence Tomography ImageCIOD
Ophthalmic Thickness MapCIOD
Surface Scan MeshCIOD
Surface Scan Point CloudCIOD
Legacy Converted Enhanced CT ImageCIOD
Legacy Converted Enhanced MR ImageCIOD
Legacy Converted Enhanced PET ImageCIOD
Corneal Topography MapCIOD
Breast Projection X-Ray ImageCIOD
Parametric MapCIOD
Wide Field Ophthalmic Photography Stereographic Projection ImageCIOD
Wide Field Ophthalmic Photography 3D Coordinates ImageCIOD
Tractography ResultsCIOD
RT Brachy Application Setup Delivery InstructionCIOD
Planar MPR Volumetric Presentation StateCIOD
Volume Rendering Volumetric Presentation StateCIOD
Content Assessment ResultsCIOD
CT Performed Procedure ProtocolCIOD
CT Defined Procedure ProtocolCIOD
Protocol ApprovalCIOD
XA Performed Procedure ProtocolCIOD
XA Defined Procedure ProtocolCIOD
Ophthalmic Optical Coherence Tomography En Face ImageCIOD
Ophthalmic Optical Coherence Tomography B-scan Volume AnalysisCIOD
Encapsulated STLCIOD
Encapsulated OBJCIOD
Encapsulated MTLCIOD
RT Physician IntentCIOD
RT Segment AnnotationCIOD
RT Radiation SetCIOD
C-Arm Photon-Electron RadiationCIOD
Tomotherapeutic RadiationCIOD
Robotic-Arm RadiationCIOD
RT Radiation Record SetCIOD
RT Radiation Salvage RecordCIOD
C-Arm Photon-Electron Radiation RecordCIOD
Tomotherapeutic Radiation RecordCIOD
Robotic-Arm Radiation RecordCIOD
RT Radiation Set Delivery InstructionCIOD
RT Treatment PreparationCIOD
Enhanced RT ImageCIOD
Enhanced Continuous RT ImageCIOD
RT Patient Position Acquisition InstructionCIOD
Microscopy Bulk Simple AnnotationsCIOD
Photoacoustic ImageCIOD
Confocal Microscopy ImageCIOD
Confocal Microscopy Tiled Pyramidal ImageCIOD
Basic DirectoryCIOD

Built with by Innolitics, a team of medical imaging software developers.

Data synced with official DICOM standard on 18 April 2024. The DICOM Standard is under continuous maintenance, and the current official version is available at DICOM Parts 3, 4, and 6, © NEMA. Please note that the most recent PDF version of the standard is the official reference, and should checked when making technical decisions.

Signature Attribute

TypeRequired (1)
Value Multiplicity1
Value RepresentationOther Byte String (OB)

The MAC generated as described in Section C. and encrypted using the algorithm, parameters, and private key associated with the Certificate of the Signer (0400,0115). See Section C.

Section C.

C. Data Elements Signed

The Data Elements Signed Attribute shall list the Tags of the Data Elements that are included in the MAC calculation. The Tags listed shall reference Data Elements at the same level as the Mac Parameters Sequence (4FFE,0001) Data Element in which the Data Elements Signed Attribute appears. Tags included in Data Elements Signed shall be listed in the order in which they appear within the Data Set.

The following Data Elements shall not be included either implicitly or explicitly in the list of Tags in Data Elements Signed, nor included as part of the MAC calculation:

  • The Length to End (0008,0001) or any Tag with an element number of 0000 (i.e., no Data Set or group lengths may be included in MAC calculations)

  • Tags with a group number less than 0008

  • Tags associated with Data Elements whose VR is UN

  • Tags of Data Elements whose VR is SQ, where any Data Element within that Sequence of Items has a VR of UN recursively

  • Tags with a group number of FFFA (e.g., the Digital Signatures Sequence)

  • MAC Parameters Sequence (4FFE,0001)

  • Data Set Trailing Padding (FFFC,FFFC)

  • Item Delimitation Item (FFFE,E00D)


  1. The Length to End and group lengths can change if non-signed Data Elements change, so it is not appropriate to include them in the MAC calculation.

  2. Since the Data Element Tags that identify a Sequence and the start of each Item are included in the MAC calculation, there is no need to include the Item Delimitation Item Tags.

If any of the Data Element Tags in the list refer to a Sequence of Items, then the Tags of all Data Elements within all Items of that Sequence shall be implicitly included in the list of Data Elements Signed, except those disallowed above. This implicit list shall also include the Item Tag (FFFE,E000) Data Elements that separate the Sequence Items and the Sequence Delimitation Item (FFFE,E0DD).


It is possible to sign individual Items within a Sequence by including the Digital Signatures Macro in that Sequence Item. In fact, this is a highly desirable feature, particular when used in the context of reports. The Digital Signatures Macro is applied at the Data Set level, and Sequences of Items are merely Data Sets embedded within a larger Data Set. Essentially, the Digital Signatures Macro may be applied recursively.

An example of nesting Digital Signatures within Data Elements is illustrated in Figure C.12-1.

Figure C.12-1. Example of Nesting Digital Signatures (Informative)

In this example, there is main signature covering the pixel data and a few other Data Elements, plus two individually signed Items within a Sequence.

For Data Elements with a VR OB (e. g. pixel data) that have an undefined length (i.e., the data is encapsulated as described in PS3.5), the Item Data Element Tags that separate the fragments shall implicitly be included in the list of Data Elements Signed (i.e., a Data Element with a VR of OB is encoded in the same fashion as a Sequence of Items).

Section C.

C. Signature

To generate the MAC, Data Elements referenced either explicitly or implicitly by the Tags in the Data Elements Signed (0400,0020) list shall be encoded using the Transfer Syntax identified by the MAC Calculation Transfer Syntax UID (0400,0010) of the MAC Parameters Sequence (0400,0010) Item where the Data Elements Signed (0400,0020) Attribute appears. Data shall be formed into a byte stream and presented to the algorithm specified by MAC Algorithm (0400,0015) for computation of the MAC according to the following rules:

For all Data Elements except those with a VR of SQ or with a VR of OB with an undefined length, all Data Element fields, including the Tag, the VR, the reserved field (if any), the Value Length, and the Value, shall be placed into the byte stream in the order encountered.

For Data Elements with a VR of SQ or with a VR of OB with an undefined length, the Tag, the VR, and the reserved field are placed into the byte stream. The Value Length shall not be included. This is followed by each Item Tag in the order encountered, without including the Value Length, followed by the contents of the Value for that Item. In the case of an Item within a Data Element whose VR is SQ, these rules are applied recursively to all of the Data Elements within the Value of that Item. After all the Items have been incorporate into the byte stream, a Sequence Delimitation Item Tag (FFFE,E0DD) shall be added to the byte stream presented to the MAC Algorithm, regardless of whether or not it was originally present.


Since the Value Length of Data Elements with a VR of SQ can be either explicit or undefined, the Value Lengths of such Data Elements are left out of the MAC calculation. Similarly, the Value Length of Data Elements with a VR of OB with an undefined length are also left out so that they are handled consistently. If such Data Elements do come with undefined lengths, including the Item Tags that separate the Items or fragments insures that Data Elements cannot be moved between Items or Fragments without compromising the Digital Signature. For those Data Elements with explicit lengths, if the length of an Item changes, the added or removed portions would also impact the MAC calculation, so it is not necessary to include explicit lengths in the MAC calculation. It is possible that including the Value Lengths could make cryptanalysis easier.

After the fields of all the Data Elements in the Data Elements Signed list have been placed into the byte stream presented to the MAC Algorithm according to the above rules, all of the Data Elements within the Digital Signatures Sequence Item except the Certificate of Signer (0400,0115), Signature (0400,0120), Certified Timestamp Type (0400,0305), and Certified Timestamp (0400,0310) shall also be encoded according to the above rules, and presented to the MAC algorithm (i.e., the Attributes of the Digital Signature Sequence Item for this particular Digital Signature are also implicitly included in the list of Data Elements Signed, except as noted above).

The resulting MAC code after processing this byte stream by the MAC Algorithm is then encrypted as specified in the Certificate of Signer and placed in the Value of the Signature Data Element.


  1. The Transfer Syntax used in the MAC calculation may differ from the Transfer Syntax used to exchange the Data Set.

  2. Digital Signatures require explicit VR in order to calculate the MAC. An Application Entity that receives a Data Set with an implicit VR Transfer Syntax may not be able to verify Digital Signatures that include Private Data Elements or Data Elements unknown to that Application Entity. This also true of any Data Elements whose VR is UN. Without knowledge of the Value Representation, the receiving Application Entity would be unable to perform proper byte swapping or be able to properly parse Sequences in order to generate a MAC.

  3. If more than one entity signs, each Digital Signature would appear in its own Digital Signatures Sequence Item. The Digital Signatures may or may not share the same MAC Parameters Sequence Item.

  4. The notion of a notary public (i.e., someone who verifies the identity of the signer) for Digital Signatures is partially filled by the authority that issued the Certificate of Signer.

Table C. lists the Defined Terms for MAC Algorithm (0400,0015).

Table C. Defined Terms for MAC Algorithm (0400,0015)

Defined Term



[ISO/IEC 10118-3]




See also security considerations in [RFC6151]. The use of MD5 is no longer recommended.


[FIPS PUB 180-4]


[FIPS PUB 180-4]


[FIPS PUB 180-4]


[FIPS PUB 180-4]


[FIPS PUB 180-4]


[FIPS PUB 180-4]


[FIPS PUB 180-4]


[FIPS PUB 202]


[FIPS PUB 202]


[FIPS PUB 202]


[FIPS PUB 202]


Security Profiles (see PS3.15) may restrict or extend the list of MAC algorithms that are permitted or required by a specific profile.