ManTech is seeking a motivated, career and customer-oriented **Information System Security Engineer (ISSE)** to join our team in **Linthicum Heights, MD** . This role is vital for ensuring the confidentiality, integrity, and availability of systems within secure environments. The ISSE will provide cybersecurity and systems engineering support to: + Link Encryptor Family (LEF) development, evaluation and certification efforts. + Ensure interoperability between LEF implementations by specifying requirements and verifying compliance. Develop new versions of the LEF Cryptographic Interoperability Specification (LEFCIS) and maintain existing versions. + Provide laboratory engineering support and participate in planning, setup, testing, and reporting of security, functionality, interoperability, and conformance testing of LEF products. **Minimum requirements needed to qualify for the role:** + Fourteen years experience as an ISSE on programs and contracts of similar scope, type, complexity within the Federal Government is required. + Bachelor’s degree in computer science, Information Assurance, Information Security System Engineering or related discipline from an accredited college or university is required. + Four years of additional ISSE experience may be substituted for a bachelor’s degree. + DoD 8570 compliance with IASAE Level 2 is required, CISSP Certification + Understanding of encryption technologies and cryptographic principles. + Knowledge of system certification and accreditation (C&A) processes. + Experience in performing vulnerability assessments, threat modeling, and risk analysis. + Knowledge of network devices, including routers, switches, firewalls, and intrusion detection/prevention systems. + Understanding of networking concepts and protocols, including serial communications (EIA-530, EIA-422/423, EIA-232, EIA-644), TCP/IP, HTTP/S, SSL/TLS, and RESTCONF/YANG. + Knowledge of Operating Systems, including Linux, Windows and VMware **Preferred Qualifications:** + Deep understanding of symmetric and asymmetric key management techniques and principles. + Experience with encryptors, secure communications, and cryptographic product evaluation. + Familiarity with the agency’s Information Assurance Security Requirements Directive (IASRD) and Security Evaluation Requirements Document (SERD) requirements and security methods necessary to meet requirements. + Experience reviewing and analyzing security documentation required to obtain agency certification + Experience with test equipment and analysis tools, including oscilloscopes, logic analyzers, network sniffers, and LAN/WAN testers. + Experience with installation, configuration, and use of Link Encryptor Family devices, including KIV-7M. + Knowledge of Tactical Data Links, such as Link-11, Link-16, and Link-22. + Knowledge of satellite system Ground Operating Equipment encryptors, such as MYK-15A, MYK-16B, MYK-17B, and GRYPHON. + Knowledge of the Link Encryptor Family Cryptographic Interoperability Specification (LEFCIS). + Experience in the development and operation of LEFCIS compliant products. + Experience developing Operational Security Doctrine and policies that define cybersecurity objectives for the protection and use of LEF devices. + Experience in designing security solutions to mitigate risks and ensure compliance with government regulations (e.g., RMF, FISMA, NIST 800-53). + Certifications relevant to Linux or specific networking technologies are a plus (e.g., RHCSA, RHCE, or CCNA). **Clearance Requirements:** + Must have a current/active TS/SCI w/ Polygraph **Physical Requirements:** + Must be able to remain in a stationary position 50% of the time. Occasionally move about inside the office to access file cabinets, office machinery, or to communicate with co-workers, management, and customers, via email, phone, and or virtual communication, which may involve delivering presentations. ManTech International Corporation, as well as its subsidiaries proactively fulfills its role as an equal opportunity employer. We do not discriminate against any employee or applicant for employment. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, or status as a protected veteran. If you are a qualified individual with a disability and require a reasonable accommodation to apply for a position with ManTech through its online applicant system, please email us at careers@mantech.com and provide your name and contact information.