During the 1980s, Laura Holmes served as a career cryptanalyst and supervisor against a series of challenging manual cryptosystems. She also developed considerable expertise in an impressive number of target languages.

Her office analyzed about 100 manual systems from a variety of targets. None of the systems were monoalphabetic; all contained some nontrivial trick that made their analysis especially difficult. In many cases, the problem was marked by small quantities of traffic. Despite these tough obstacles Ms. Holmes, had an unexpectedly high rate of success.

Ms. Holmes also taught cryptanalysis to interns as a pragmatic application of technique and knowledge. She was a master of classic systems, plus modern variants, and conveyed as much target knowledge as her interns could absorb. She demonstrated to interns that knowledge of a nation's military structure, its culture, and current events all contributed to the process of cryptanalysis.

One of her interns described her this way:

From her knowledge of targets' past practices she could relate a supposedly "new" system back to something the target had used in the past - not by looking up the written records but just by tapping into her memory. Patience combined with sheer doggedness was her virtue as a cryppie. She would just "worry" a system to death until she recovered as much as possible, going back to plug newly recovered values into old messages, working back and forth to fill in the blanks-all by hand mind you.

On at least one occasion she was instrumental in re-establishing the ability to work against a long-dormant analytic problem. Her memory for facets of different systems was legendary, and she was meticulous in preserving the knowledge she had gained by analysis.

Her quiet abilities often were the difference between success and failure in cryptanalytic problems of the late 20th century. She also inspired and mentored both her colleagues and budding cryptanalysts to do what seemed beyond the possible. Her legacy as a master of the cryptanalytic craft remains an inspiration to cryptologists today.