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KY-57 voice encryptor. Note fill port in center.
A KYK-13 fill device.

A fill device or key loader is a module used to load cryptographic keys into electronic encryption machines. Fill devices are usually hand held and electronic ones are battery operated.

Older mechanical encryption systems, such as rotor machines, were keyed by setting the positions of wheels and plugs from a printed keying list. Electronic systems required some way to load the necessary cryptovariable data. In the 1950s and 1960s, systems such as the U.S. National Security Agency KW-26 and the Soviet Union's Fialka used punched cards for this purpose. Later NSA encryption systems incorporated a serial port fill connector and developed several common fill devices (CFDs) that could be used with multiple systems. A CFD was plugged in when new keys were to be loaded. Newer NSA systems allow "over the air rekeying" (OTAR), but a master key often must still be loaded using a fill device.

NSA uses two serial protocols for key fill, DS-101 and DS-102. Both employ the same U-229 6-pin connector type used for U.S. military audio handsets, with the DS-101 being the newer of the two serial fill protocols. The DS-101 protocol can also be used to load cryptographic algorithms and software updates for crypto modules.

Besides encryption devices, systems that can require key fill include IFF, GPS and frequency hopping radios such as Have Quick and SINCGARS.

Common fill devices employed by NSA include:

  • Next Generation Load Device-Medium (NGLD-M) - replacement for the Simple Key Loader.[1]
  • AN/PYQ-10 Simple Key Loader (SKL) - originated in 2006 as a replacement for the DTD.
  • KIK-30, a more recent fill device, is trademarked as the "Really Simple Key Loader" (RASKL) with "single button key-squirt." It supports a wide variety of devices and keys.[2]
  • KYK-28 pin gun used with the NESTOR (encryption) system
  • KYK-13 Electronic Transfer Device
  • KYX-15 Net Control Device[3]
  • MX-10579 ECCM Fill Device (SINCGARS)[4]
  • KOI-18 paper tape reader. Can read 8-level paper or PET tape, which is manually pulled through the reader slot by the operator. It is battery powered and has no internal storage, so it can load keys of different lengths, including the 128-bit keys used by more modern systems. The KOI-18 can also be used to load keys into other fill devices that do have internal storage, such as the KYK-13 and AN/CYZ-10. The KOI-18 only supports the DS-102 interface.
  • AN/CYZ-10 Data Transfer Device (DTD) - a small PDA-like unit that can store up to 1000 keys, maintains an automatic internal audit trail of all security-relevant events that can be uploaded to the LMD/KP, encrypts key for storage, and is programmable. It is capable of keying multiple information systems security (INFOSEC) devices and is compatible with such COMSEC equipment as SINCGARS radios, KY-57 VINSON, KG-84, and others that are keyed by common fill devices (CFDs). The AN/CYZ-10 supports both the DS-101 and DS-102 interfaces. It was developed in the early 1990s, weighs about 4 lb (1.8 kg), and was designed to be fully compatible with future INFOSEC equipment meeting DS-101 signaling and benign fill standards. It will eventually replace the legacy family of CFDs, including the KYK-13, KYX-15 electronic storage devices, and the KOI-18 paper tape reader. Only the DTD and the KOI-18 support newer, 128-bit keys.
  • Secure DTD2000 System (SDS) - Named KIK-20, this was the next generation common fill device replacement for the DTD when it started production in 2006. It employs the Windows CE operating system.[5]
  • KSD-64 Crypto ignition key (CIK)

The older KYK-13,[6] KYX-15 and MX-10579 are limited to certain key types.

See also

[edit]

References

[edit]
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Fill device

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from Grokipedia
A fill device is a communications security (COMSEC) item used to transfer or store cryptographic keys in electronic form or to insert keys into cryptographic equipment. These devices are essential for securely loading encryption variables, such as transmission encryption keys (TEK), transmission security keys (TSK), and key encryption keys (KEK), into military and secure communication systems like radios and encryption machines. Fill devices are typically handheld and portable, designed for rugged field use, and often feature specialized connectors like the U-283 (6-pin) or U-229 (5-pin) to interface with target equipment. Early models, such as the KYK-13, operated using the DS-102 protocol for synchronous serial key transfer, while modern variants employ the more versatile DS-101 protocol to handle diverse data types including frequency hopping tables, GPS keys, and software updates. Common examples include the KYK-13 and KYK-15 for basic key loading, as well as advanced electronic fill devices like the Data Transfer Device (DTD), Simple Key Loader (SKL), Secure (SDS), Remote Access Smartcard Key Insertion (RASKI), and the emerging Next Generation Load (NGLD) (as of 2025). Specified, certified, and overseen primarily by the U.S. (NSA), with development and by defense contractors, these devices ensure the secure distribution of cryptographic without exposing keys to , forming a critical component of electronic warfare and secure communications infrastructure.

Overview

Definition

A fill device, also known as a key loader or electronic fill device (EFD), is a (COMSEC) item designed to transfer, store, or insert cryptographic keys in electronic form into encryption equipment. These devices facilitate the secure loading of keys, such as traffic encryption keys (TEKs) or key encryption keys (KEKs), into cryptographic systems, ensuring protected communications in military and secure environments. Typically, a fill device takes the form of a handheld electronic module, ruggedized for field use and powered by batteries to enable portability. Fill devices differ fundamentally from earlier mechanical keying methods, which relied on manual configuration using printed lists or physical adjustments, such as setting rotor wheels in machines like the Enigma based on instructions. In contrast, fill devices automate the process through electronic means, reducing human error in . At their core, fill devices generally incorporate a for processing key operations, to securely store keys, and physical interfaces—such as the U-283 or U-229 connectors—for direct connection to target equipment. This hardware configuration supports standardized protocols for key transfer, marking an evolution from labor-intensive, paper-based or manual distribution systems to efficient, tamper-resistant electronic solutions that enhance operational security in modern .

Purpose and Functionality

Fill devices serve as essential components in (COMSEC) systems, primarily designed to enable the secure distribution of cryptographic variables, including Transmission Encryption Keys (TEK) for user data, Transmission Security Keys (TSK) for protecting radio signals from exploitation, and Key Encryption Keys () for safeguarding other keys during transfer. By facilitating the electronic loading of these keys into end-user equipment, fill devices prevent exposure of sensitive key material to manual handling or , thereby minimizing risks of compromise during distribution. In functionality, fill devices act as intermediaries within electronic key management systems like the (EKMS), bridging key generation sources in secure facilities (such as Tier 2 accounts) to operational end-user devices at local elements (Tier 3). They support both wired and over-the-air key updates, including over-the-air rekeying (OTAR), over-the-air distribution (OTAD), and over-the-air transfer (OTAT), allowing for efficient insertion of keys into cryptographic equipment without physical transport of hard-copy material. This process ensures keys are stored, transferred, and loaded in encrypted (black) form, with features like zeroization to securely erase data when needed. The use of fill devices offers significant benefits in cryptographic operations, including reduced associated with manual key entry, faster reconfiguration of systems during missions, and enhanced operational flexibility through automated . By automating the key insertion process into devices like radios and encryptors, they streamline while maintaining strict protocols, such as two-person for handling high-classification keys.

History

Early Development

The development of fill devices emerged in the amid U.S. military requirements for secure electronic encryptors, particularly to support the transition from mechanical rotor-based systems to technology for high-speed communications. The (NSA), established in 1952, initiated projects to secure teletypewriter circuits operating continuously, leading to the creation of devices like the KW-26, an online cryptographic system introduced around 1958 for teleprinters at speeds up to 74 baud. This shift addressed the limitations of World War II-era rotor machines, such as the SIGABA (also known as ECM Mark II), which relied on manual keying via printed lists specifying rotor arrangements, pin settings, and alignments for daily use, making key distribution cumbersome and vulnerable to compromise. A pivotal innovation was the first common fill device (CFD), designed in 1952 by engineer Charles Napier for the KW-26 project under NSA oversight. This device utilized punched IBM cards in a proprietary RemRand format—featuring 45 columns with round holes—to securely store and transfer daily cryptographic variables, such as keys and initialization vectors, into the encryptor. The CFD marked a departure from manual methods by enabling electronic key loading, which was essential for handling the increased complexity of electronic systems that generated longer, more frequent key changes compared to the static setups of rotor machines. Burroughs Corporation, contracted in 1953, integrated this technology into early KW-26 prototypes delivered by 1955, with final models following in 1957. By the early 1960s, over 14,000 KW-26 units had been deployed across the Department of Defense and intelligence agencies, standardizing electronic key distribution and enhancing operational security for point-to-point record traffic. The NSA's emphasis on traffic flow security and compatibility with commercial circuits further drove these advancements, replacing printed key lists with tamper-evident, punched-card media that could be physically destroyed after use per (COMSEC) protocols. This foundational work laid the groundwork for scalable in Cold War-era cryptography.

Modern Advancements

In the 1970s, the (NSA) introduced the DS-102 protocol to standardize synchronous key transfer for early electronic cryptographic devices, marking a significant shift from manual and mechanical methods to more reliable electronic interfaces. This protocol facilitated secure, wired loading of encryption keys into equipment like early voice encryptors, addressing the limitations of analog systems by enabling precise digital synchronization over a 6-pin U-229 connector commonly used in military audio handsets. By the 1980s, the NSA shifted to the DS-101 protocol, an asynchronous standard that superseded DS-102 and improved compatibility with emerging transistor-based encryptors. Unlike its predecessor, DS-101 allowed for more flexible data rates and error correction, supporting broader across diverse hardware without strict timing requirements, which was essential as cryptographic systems transitioned to . The 1990s brought innovations in handheld fill devices, exemplified by the AN/CYZ-10, which replaced bulkier older models with battery-powered, ruggedized designs optimized for field deployment. Weighing approximately 4 pounds and supporting both DS-101 and DS-102 protocols, this device enhanced mobility for troops by enabling secure key storage and transfer in austere environments, while incorporating LCD displays for user verification. In the , fill devices evolved to support software-defined radios, GPS-secure keys, and over-the-air rekeying (OTAR), aligning with NSA's evolving cryptographic standards, including the transition from Suite B to the Commercial National Security Algorithm (CNSA) Suite in 2015 and CNSA 2.0 in 2024 for quantum resistance. In 2005, the Simple Key Loader (SKL) was introduced as an advanced successor to the AN/CYZ-10, providing enhanced key management capabilities compatible with CNSA algorithms. These advancements allow dynamic key updates via radio networks without physical connections, as seen in systems like , reducing logistical burdens and enabling real-time adaptation in networked operations. CNSA algorithms, including AES-256 and , underpin these capabilities, ensuring compatibility with modern digital ecosystems while maintaining high security levels.

Types and Examples

Common Fill Devices

Common fill devices in the U.S. military primarily consist of standardized electronic key loaders developed by the (NSA) to facilitate secure cryptographic key distribution for (COMSEC) equipment. These devices ensure interoperability across various encryption systems by adhering to NSA-endorsed protocols, such as DS-102 for key transfer, and are designed for rugged field use in tactical environments. The KYK-13, introduced in 1976, represents one of the earliest widely adopted fill devices, powering operations with a 6.5V battery (BA-1372/U or BA-5372/U) for reliable key storage and transfer. It supports keys up to 128 bits in length and employs the DS-102 protocol to load cryptographic material into compatible radios, including the system, as well as devices like the KG-84 encryptor and STU-II . With a compact design measuring 130 x 63 x 35 mm and weighing 338 grams (including battery), the KYK-13 features dual U-229 connectors for male-to-female transfers, internal for up to six traffic encryption keys (TEKs), and a zeroize function for secure erasure, making it a staple for frontline COMSEC keying despite its age. Developed by the NSA in the early 1990s with initial production in 1993, the AN/CYZ-10, also known as the Data Transfer Device (DTD), advanced by supporting both DS-101 and DS-102 interfaces for broader compatibility with Type 1 systems. This handheld device stores up to 1,000 keys in battery-backed , enabling secure receipt, storage, and transfer of cryptographic data for equipment such as radios, KY-57 encryptors, and KIV-7 modules, while maintaining an of security events. Weighing approximately 4 pounds (1.8 kg) in its weather-resistant plastic case (16 x 11 x 5.5 cm when closed), the AN/CYZ-10 incorporates a , LCD display, and Crypto Ignition Key (CIK) for operator authentication, ensuring controlled access in and operations. The MX-18290, developed in the late 1980s and entering production in the early , serves as a specialized electronic device for distributing frequency hopping (FH) tables and keys (TSKs) across multiple cryptographic networks. Powered by a 6V military battery (BA-1372/BA-5372) requiring annual replacement, it uses the DS-102 interface via 6-pin U-229 connectors to fill radio sets with up to 13 FH sets and 2 TSKs, enhancing (ECCM) in tactical communications. Its design, similar in form to the KYK-13, prioritizes secure, one-way key to prevent during distribution. These devices, including the KYK-13, AN/CYZ-10, and MX-18290, conform to NSA's COMSEC guidelines under the (EKMS), which mandates standardized interfaces and protocols to guarantee among U.S. Armed Forces and allied systems. The Central Office of Record (COR) within NSA oversees compliance, ensuring that fill devices integrate seamlessly with global COMSEC programs for key generation, distribution, and accountability.

Specialized and Foreign Devices

The KSD-64 is a specialized key storage device developed by the U.S. (NSA) in collaboration with Datakey Electronics Inc. in 1986, primarily for use with secure telephones produced by manufacturers such as , , and RCA. It functions as a Crypto Ignition Key (CIK) that can be inserted into a keyceptacle on the telephone for activation via a 90-degree rotation, enabling communications, but it is also configurable as a fill key generator or loader for transferring initial seed keys or operational keys to the device. The KSD-64 utilizes a 64 Kbit parallel with 28 contacts and proprietary interfaces, including loading via the PKS-703 keyloader connected to a PC through an port, distinguishing it from standard fill devices by its role in both storage and targeted key ignition for specific secure phone systems. Production continued until 2015, after which it was replaced by the compatible PK-64KC model. The , known as the Simple Key Loader (SKL), represents a U.S. specialized fill device optimized for in tactical environments, developed to supplement and eventually replace the AN/CYZ-10 Data Transfer Device. It securely receives, stores, and transfers (COMSEC) keys, Electronic Protection (EP) data, and Signal Operating Instructions (SOI) using an embedded NSA KOV-21 encryptor card, supporting over 150 end cryptographic units through DS-101 and DS-102 interfaces as well as KSD-64 compatibility. Ruggedized for handheld use in field operations, the SKL integrates with the (EKMS) to facilitate over-the-air rekeying when paired with compatible equipment, enhancing rapid in dynamic tactical scenarios without relying on physical tape or legacy methods. Over 24,000 units were produced between 2005 and 2007 at a of approximately $1,708. As of 2025, the SKL is facing obsolescence, with the U.S. Army developing the Next Generation Load Device-Medium (NGLD-M) under a 2022 contract to to replace it. Foreign fill devices often adapt or parallel U.S. standards like DS-101 for while incorporating domestic cryptographic protocols. The UP-2001 (also designated PKMX-2001), developed by Crypto in the in 1990, serves as an electronic key-filler for distributing Transmission Encryption Keys (TEK) in military systems such as the ZODIAC network, Spendex 40, Spendex 50, and BVO encryptors via the U-229 connector. Featuring 40 key compartments selectable by a and activated via a , it lacks direct DS-101 support but exemplifies European adaptations for secure key transfer in NATO-aligned environments, with production succeeded by the UP-2101 in 1992. In contrast to common U.S. standardization around DS-101 protocols, European devices like the IT-DTD from Italian firm Leonardo demonstrate adaptations for interoperability by supporting both DS-101 and DS-102 interfaces alongside multiple common fill devices. This rugged, battery-powered handheld unit is designed for terrestrial, naval, and aerial operations, enabling secure key material transfer to encryptors while accommodating domestic enhancements for allied systems.

Operation

Key Transfer Process

The key transfer process using a fill device begins with preparation, where authorized personnel authenticate access to the device, typically via a Crypto-Ignition Key (CIK) or PIN entry, ensuring only cleared individuals with a need-to-know can proceed. The device receives cryptographic keys from a secure source, such as an Electronic Key Management System (EKMS) Local Management Device/Key Processor (LMD/KP) or a couriered fill tape, under two-person integrity for higher classifications like TOP SECRET to maintain accountability. For example, in systems like the KYK-13, keys are pre-loaded into the device via a key management system before field use. Once prepared, the fill device establishes a physical connection to the target cryptographic equipment, such as a radio or secure terminal, using standardized connectors like the U-283 (6-pin) or U-229 (5-pin) interface for secure, wired linkage. The power-on sequence follows, with both devices powered up in a controlled environment approved for classified , often requiring verification of battery status and cable integrity to prevent interruptions. This step ensures a tamper-evident setup, with personnel maintaining continuous visual control during linkage. The core transfer steps involve initiating fill mode on the target device, such as setting a radio like to "LD" (load) mode, and selecting the key type—commonly a Traffic Key (TEK)—from the fill device's register. The operator then activates the transfer, often by pressing a load or push-to-talk mechanism, allowing keys to flow electronically without exposure; integrity is confirmed through built-in or parity verification, indicated by device lamps or audio tones. In the KYK-13 procedure, for instance, the selector switch is positioned to the desired key slot, and transfer completes with a parity lamp signaling successful insertion. Following transfer, the fill device erases any temporary key storage to minimize retention risks, and operators log the event in audit trails, including details like key short title, serial number, and personnel involved, for reconciliation with the central authority. The connection is disconnected, and the target device is returned to operational mode, such as "C" (cipher) on a VINSON unit. Error handling protocols address failed transfers by first attempting through repetition of the connection and steps, ensuring no key fragments remain. If issues persist, such as a parity mismatch or device malfunction, the fill device or target undergoes zeroization—automatic or manual erasure of all keys—to render it secure before reporting the incident via a COMSEC discrepancy to the responsible officer. This prioritizes rapid recovery while documenting anomalies for accountability.

Interfaces and Protocols

Fill devices rely on standardized physical and logical interfaces to ensure secure and compatible transfer of cryptographic keys to end-user equipment such as radios and encryptors. The primary connectors for key fill operations in U.S. military systems are the U-283 (6-pin) and U-229 (5-pin) series, variants of the MIL-DTL-55116 military-standard circular connector family. These connectors facilitate connections between fill devices and target equipment, with pins dedicated to data, clock, ground, and auxiliary signals, enabling both audio functions and dedicated key loading in cryptographic applications. The DS-102 protocol, developed by the National Security Agency (NSA), is a synchronous bit-serial standard introduced in the early 1980s for transferring cryptographic key material. Defined in the EKMS-608 specification, it employs separate data and clock lines, with the fill device generating the clock signal at a variable baud rate for key block transfers. Each key block consists of 128 bits, including 120 data bits and an 8-bit checksum, supporting secure loading into devices like the KYK-13 fill unit and compatible encryptors. In contrast, the DS-101 protocol represents a more modern , also standardized by the NSA under EKMS-603, which operates at a fixed rate of 64 kbps over or physical layers. It incorporates the (HDLC) framing for error detection via cyclic redundancy checks (CRC) and supports structured frames that can include elements, along with tagging to distinguish key material from updates or frequency-hopping tables. This protocol enhances flexibility for loading cryptographic algorithms and mission , maintaining with DS-102 systems through the shared U-229 connector. Older fill systems may utilize RS-232 serial interfaces for compatibility with legacy equipment, while contemporary proprietary devices increasingly incorporate USB or Ethernet adapters to bridge traditional protocols like DS-101 to networked environments. For instance, Ethernet converters enable remote key distribution by translating DS-101/RS-232 or DS-102 signals over IP networks, preserving protocol integrity for secure transfers. These interfaces collectively ensure interoperability, as demonstrated by the KG-84 encryptor's use of the U-229 port and DS-102 protocol for loading up to four 128-bit traffic encryption keys from standard fill devices like the KYK-13.

Security Considerations

Protection Mechanisms

Fill devices employ tamper-evident hardware to detect and respond to unauthorized physical access, ensuring that cryptographic keys cannot be extracted or compromised. These mechanisms often include features, such as zeroization, which rapidly erases all stored keys upon detection of a breach, rendering the device inoperable for key recovery. For instance, in the KYK-13 electronic transfer device, zeroization is activated by selecting the "Z ALL" mode, instantly destroying key data across all compartments to prevent exposure. Additionally, potting encapsulates sensitive components in cryptographic hardware, creating a hard, opaque barrier that provides evidence of tampering if breached, as seen in validated modules under standards. Stored keys within fill devices are safeguarded through using key keys (KEKs) to wrap traffic keys (TEKs) and traffic security keys (TSKs), preventing exposure in memory. This hierarchical protection aligns with NSA-approved protocols like DS-102, where KEKs ensure secure storage and transfer of up to 128-bit keys, including checksums for integrity. Modern implementations commonly utilize strong symmetric for this wrapping, compliant with federal cryptographic standards for protecting classified material. Access controls in fill devices restrict key loading and transfer to authorized users through multi-factor methods, combining physical interfaces with . Devices like the KYK-13 require physical connection via standardized U-229 connectors and manual selection of key compartments, limiting operations to direct hardware access without remote or unauthorized entry. Advanced models, such as the Simple Key Loader (SKL), incorporate role-based limits and removable cryptographic ignition keys (CIKs) as physical tokens, alongside PIN-based to enforce user roles and prevent unauthorized fills. These controls ensure compliance with (EKMS) policies for secure key distribution. Audit logging capabilities in fill devices record all key operations for traceability and accountability, capturing details such as transfers, loads, and zeroizations. These logs support post-incident analysis and routine compliance checks under NSA's COMSEC standards, including the Material Control System (COMDT), which mandates documentation of all to detect anomalies. For example, the SKL generates logs of activities that align with EKMS auditing requirements, facilitating 100% verification of top-secret keying material during account audits. To counter reverse engineering attempts, fill devices utilize obfuscated firmware and secure boot processes that verify code integrity before execution, preventing unauthorized modifications or extraction of proprietary algorithms. In NSA-endorsed designs, such as those using DS-101/DS-102 interfaces, firmware obfuscation hides and transfer logic, while secure boot chains ensure only validated software runs, as implemented in ruggedized units like the SKL to maintain operational against dissection or . These measures draw from broader cryptographic hardware practices to protect against theft and side-channel attacks.

Vulnerabilities and Mitigations

Fill devices, being portable and often battery-powered, are susceptible to physical vulnerabilities such as side-channel attacks that exploit power consumption patterns during cryptographic operations. For instance, differential power analysis (DPA) can reveal key material by monitoring variations in a device's electricity usage, particularly in battery-operated units like early models that lack advanced shielding. To mitigate these risks, manufacturers incorporate electromagnetic shielding and low-emission circuit designs to minimize detectable leakage, ensuring compliance with standards like those outlined in COMSEC guidelines. Insider threats pose a significant to fill devices through unauthorized extraction of stored keys, often by personnel with legitimate access who may defect, engage in , or commit . Such threats are addressed through rigorous chain-of-custody protocols, including formal hand receipts (SF 153) for transfers and mandatory inventories within 24 hours of custodian changes, as required by U.S. Army COMSEC policies. Additionally, periodic zeroization—erasing all keys via dedicated functions—prevents retention of sensitive material during handovers or emergencies, with certification statements verifying destruction. Early key fill protocols like DS-102, a synchronous serial standard for transferring keys without built-in , were vulnerable to replay attacks where intercepted could be retransmitted to inject false keys. This weakness was addressed in the successor DS-101 protocol, an asynchronous HDLC-based standard that provides improved security for . risks for fill devices include the introduction of units, which could contain backdoors or fail to securely handle keys, as highlighted in Department of Defense assessments of electronic components. Mitigation relies on NSA certification for Type 1 COMSEC devices, ensuring cryptographic integrity, combined with serialized tracking and vendor audits to verify authenticity throughout . Historical incidents involving lost fill devices, such as reportable cases of missing keyed common fill units like the KYK-13, have underscored the need for enhanced safeguards; these rare compromises, including physical loss or tampering, have underscored the need for enhanced safeguards in modern models.

Applications

Military and Government Use

Fill devices play a pivotal role in U.S. , particularly for loading cryptographic keys into tactical radios such as the and the frequency-hopping system, enabling secure voice and data transmissions in combat environments. The KYK-13 electronic transfer device, introduced by the (NSA) in 1976, is a primary example, used to load transmission encryption keys (TEKs) and other COMSEC variables into radios via the AUD/FILL receptacle, supporting rapid reconfiguration for electronic warfare resistance. Similarly, for , fill devices like the KYK-13 or MX-18290 load frequency-hopping tables and data, ensuring across airborne and ground platforms during dynamic operations. These capabilities allow for quick key changes in the field, essential for maintaining secure nets amid threats. In government contexts, fill devices are integral to the NSA's (EKMS), which automates the distribution of Type 1 cryptographic keys for protecting classified () information and Type 3 keys for controlled unclassified material across agencies like the (DIA) and (FBI). EKMS Tier 1-3 components, including Local Management Devices/Key Processors (LMD/KP), generate and transfer keys to end cryptographic units via fill devices such as the Simple Key Loader (SKL) or KSD-64A, adhering to Two-Person Integrity protocols for high-security material. This system supports secure communications in joint operations, with keys loaded into devices like the KIV-7 inline encryptor or KY-58 for tactical networks. Tactical applications emphasize field rekeying for joint operations, where fill devices enable over-the-air rekeying (OTAR) to update keys in Identification Friend or Foe (IFF) transponders and satellite communication links without physical access, reducing vulnerability in forward-deployed units. For instance, the SKL facilitates loading Mode 4/5 keys into Mark XIIA IFF systems for aircraft and naval vessels, while devices like the KG-250XS support remote rekeying of High Assurance Internet Protocol Encryptor (HAIPE) networks over satellite channels. The AN/CYZ-10 Data Transfer Device serves as a versatile handheld loader for merging COMSEC and transmission security data in expeditionary settings. NATO standardization promotes shared fill devices for multinational exercises, with the KYK-13 approved under protocols for in cryptographic networks, allowing allied forces to load common keys into compatible equipment. This alignment, guided by Standardization Agreements (STANAGs), facilitates secure joint operations, as seen in exercises where U.S. and partners use equivalent devices like the RASKL (KIK-30) for one-button key fills. In the , U.S. forces employed KYK-13-compatible systems, such as with the KY-68 crypto phone, to establish secure communication nets amid multinational deployments. As of 2025, ongoing DoD crypto modernization efforts are integrating Infrastructure (KMI), allowing secure over-the-network to compatible devices, thereby reducing the need for physical fill devices in certain operational environments, such as within U.S. Southern Command (SOUTHCOM).

Commercial and Civil Use

Fill devices have been adapted for commercial applications, particularly in enterprise environments requiring compliance with standards like for secure key loading into VPN and VoIP systems. For instance, Thales provides key management devices such as the Key Management Device (KMD), a compact cryptographic tool that securely forms and transfers keys for protecting sensitive data in commercial networks, ensuring compliance with federal requirements. These variants support validated modules, enabling enterprises to load cryptographic keys offline into hardware for enhanced protection against unauthorized access in VPN tunnels and communications. In civil government sectors, fill devices are integral to securing public safety communications, especially in radios adhering to (P25) standards. Devices like the KVL 5000 Key Variable Loader are used to load AES-256 encryption keys into P25 two-way radios and infrastructure, facilitating encrypted dispatch for emergency services and preventing interception of sensitive operations. Key fill devices (KFDs) distribute these keys to subscriber units in a hardened manner, with agencies required to track and secure them to maintain interoperability across public safety networks coordinated by facilities like the National Law Enforcement Communications Center (NLECC). Emerging applications include key provisioning in civil transportation and , where fill devices support secure communications in sectors like railways and networks. Thales' transfer solutions, for example, manage key lifecycles for in civilian and rail systems, adapting military-grade technology to non-defense needs while complying with standards such as UNISIG. In , specialized key fill devices load keys into COFDM equipment for secure video and transmission in civil airborne systems. A prominent example is Leonardo's IT-DTD (Data Transfer Device), a rugged, battery-powered handheld fill device designed for securely receiving, storing, and transferring key material in networks, offering versatility for enterprise and applications beyond military contexts. However, commercial and civil use of fill devices faces limitations due to U.S. export controls on cryptographic , which restrict the export of strong to prevent proliferation of advanced tools. These regulations often require downgraded cryptographic capabilities from standards like the former NSA Suite B (now transitioned to CNSA) for global sales, ensuring compliance while limiting full-strength algorithms in international commercial products.

References

  1. https://csrc.nist.gov/glossary/term/fill_device
  2. https://www.cryptomuseum.com/crypto/fill.htm
  3. https://www.sncorp.com/capabilities/next-generation-load-device-ngld-m/
  4. https://info.publicintelligence.net/NSA-NAG-16F.pdf
  5. https://www.cryptomuseum.com/crypto/usa/mx18290/index.htm
  6. https://www.hqmc.marines.mil/Portals/137/Users/139/51/651/EKMS-1E_Final_Page_Checked_07Jun2017.pdf?ver=2017-08-17-120932-160
  7. https://rmf.org/wp-content/uploads/2017/10/CNSSI-4009.pdf
  8. https://media.defense.gov/2021/Jul/13/2002762041/-1/-1/0/TSEC_KW26.PDF
  9. https://www.nsa.gov/portals/75/documents/about/cryptologic-heritage/historical-figures-publications/publications/technology/The_SIGABA_ECM_Cipher_Machine_A_Beautiful_Idea3.pdf
  10. https://www.jproc.ca/crypto/kw26.html
  11. https://www.cryptomuseum.com/intel/nsa/ds102/
  12. https://www.cryptomuseum.com/intel/nsa/ds101/
  13. https://www.nsa.gov/resources/commercial-solutions-for-classified-program/faq/
  14. https://media.defense.gov/2024/May/30/2003728741/-1/-1/0/CSA_CNSA_2.0_ALGORITHMS.PDF
  15. https://www.cryptomuseum.com/crypto/usa/kyk13/index.htm
  16. https://www.nsa.gov/Resources/Cryptographic-support-Services/
  17. https://www.cryptomuseum.com/crypto/usa/cyz10/index.htm
  18. https://www.cryptomuseum.com/crypto/usa/cyz10/files/an_cyz10_manual.pdf
  19. https://www.cryptomuseum.com/crypto/usa/ksd64/
  20. https://www.gd.com/Articles/2022/02/07/general-dynamics-awarded-contract-to-build-next-generation-cryptographic-key-loader
  21. https://www.cryptomuseum.com/crypto/philips/up2001/
  22. https://electronics.leonardo.com/en/products/it-dtd-for-nato
  23. https://www.hqmc.marines.mil/portals/137/ekms-1b_amd-9.pdf
  24. https://irp.fas.org/doddir/army/miobc/lp-sincg.htm
  25. https://www.globalsecurity.org/military/library/policy/army/fm/11-43/c4f.htm
  26. https://apps.dtic.mil/sti/tr/pdf/ADA404995.pdf
  27. https://www.cryptomuseum.com/crypto/usa/u229/index.htm
  28. https://www.arkhamtechnology.com/cryptographic-modules/usb-ds-101-keyfill-cable-rs232
  29. https://fthinking.com/index.php/our-products/4-fill-protocol-converter-and-remote-key-fill
  30. https://www.cryptomuseum.com/crypto/usa/kg84/
  31. https://csrc.nist.gov/csrc/media/Projects/cryptographic-module-validation-program/documents/fips%2520140-3/FIPS%2520140-3%2520IG.pdf
  32. https://www.commoncriteriaportal.org/files/epfiles/128-st.pdf
  33. https://www.cryptomuseum.com/intel/nsa/ds102/index.htm
  34. https://quizlet.com/502804195/anpyq-10-or-skl-flash-cards/
  35. https://www.hqmc.marines.mil/Portals/137/ekms-1b_amd-9.pdf
  36. https://csrc.nist.gov/glossary/term/comsec_account_audit
  37. https://www.hqmc.marines.mil/Portals/137/Users/139/51/651/EKMS-3E_Final_Page_Checked_08May2017.pdf?v
  38. https://www.cryptomuseum.com/intel/nsa/ds101/index.htm
  39. https://www.sncorp.com/capabilities/simple-key-loader-skl/
  40. https://www.allaboutcircuits.com/technical-articles/a-basic-introduction-to-power-based-side-channel-attacks/
  41. https://info.publicintelligence.net/USArmy-COMSEC.pdf
  42. https://www.bis.doc.gov/index.php/documents/technology-evaluation/37-defense-industrial-base-assessment-of-counterfeit-electronics-2010/file
  43. https://radionerds.com/images/7/70/FM_11-1_SINCGARS_1996.pdf
  44. https://www.hqmc.marines.mil/Portals/137/Users/139/51/651/EKMS-1E_Final_Page_Checked_07Jun2017.pdf
  45. https://www.cryptomuseum.com/crypto/usa/nsa.htm
  46. https://gdmissionsystems.com/encryption/embedded-encryption/identification-friend-or-foe-crypto-systems
  47. https://www.viasat.com/products/cybersecurity/kg-250xs/
  48. https://www.ia.nato.int/DocumentGenerator/repository/version/e6b8a55c-f453-48da-9f0c-dbcfb1c9243d/KYK-13
  49. https://www.ia.nato.int/niapc/Product/The-Really-Simple-Key-Loader--RASKL--KIK-30_545
  50. https://www.army.mil/article/284517/special_delivery_no_longer_needed_for_comsec_keys
  51. https://cpl.thalesgroup.com/resources/encryption/key-management-device-data-sheet
  52. https://cpl.thalesgroup.com/compliance/americas/fips-140-2
  53. https://www.motorolasolutions.com/en_us/products/p25-products/security/kvl-5000.html
  54. https://project25.org/images/stories/ptig/23_0508_fpic-p25_WhoWhatWhenWhereHowWhy-Encryption-P25-LMR-Sys_FINAL_508C.pdf
  55. https://www.thalesgroup.com/en/solutions-catalogue/key-management
  56. https://www.global-aviation-systems.de/en/products-mission-flight/key-fill-device-
  57. https://electronics.leonardo.com/en/products/it-dtd
  58. https://www.bis.gov/learn-support/encryption-controls
  59. https://pomcor.com/2016/02/09/nsas-faqs-demystify-the-demise-of-suite-b-but-fail-to-explain-one-important-detail/
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