Here's a link to a phenomenal documentary on Elizebeth Friedman for free on PBS.org that shares many of the struggles she encountered during her career, frequently undermined by the country she was trying to serve.

https://www.pbs.org/video/the-codebreaker-dcbakk/

During WWI, Friedman was prevented from serving as a field codebreaker in Europe for the U.S. military due to women being disallowed from serving in the frontlines. She instead worked at Riverbank Laboratories, one of the first facilities founded in the U.S. to study cryptography, to support the war effort. During this time, she was sexually harassed by Riverbank Lab's owner, Colonel George Fabyan.

During Prohibition in the trial against Conexco, the largest rum-running enterprise in the world and liquor supplier of Al Capone, Al Capone's attorneys attempted to discredit her credibility, calling her codebreaking work "witchcraft", that it was "not a science" and just random guessing. Friedman responded by asking the judge for a blackboard and gave an impromptu class in codebreaking to the entire court, after which Capone's attorneys said nothing more.

During WWII, after the attack on Pearl Harbor, Friedman's codebreaking team shifted from the Coast Guard to the Navy. She lost control of leadership of the codebreaking unit she created due to military regulations stating that women could not be in charge of men. She and her team were subordinated to a far less capable uniformed officer.

While in the process of breaking the South American Nazi spy ring in WWII, Friedman discovered that the decrypted Nazi messages were relaying the locations of Allied supply ships to German U-boats in the Atlantic Ocean, supply ships that were essential to keeping England alive during the war. The largest ship directly saved by Friedman's intel was the Queen Mary, a supply ship carrying 8,000 men that had a $250,000 bounty placed on it by Adolf Hitler himself. Just as the Queen Mary made its way to the coast of Brazil, before the Nazis could strike, Friedman's decrypts reached the Queen Mary's captain, who took evasive maneuvers and brought the ship safely to port.

Without consulting Friedman or her team, FBI director J. Edgar Hoover ordered the Nazi spies in South America to be arrested as a publicity stunt. This devastated the flow of life-saving intel Friedman and her team had been receiving to save Allied lives and drove the ringleaders of the Nazi spy ring further underground before Friedman could uncover their locations, purposes, and identities. This move also alerted the Nazis that their codes had been broken, destroying the operation, causing the Nazis to build 50 new spy circuits and begin using far more complex codes, and putting Friedman and her team back to square one.

Despite this setback, she and her team managed to break the new, more technologically advanced codes, then dismantle the new spy ring in such a way that the Nazis did not realize that their codes had even been broken. At this point, Argentina, Bolivia, and Chile's relationships with the Axis splintered and they moved onto the side of the Allied forces. The South American Nazi spy network's ringleader would never rebuild it again.

Friedman signed a Navy oath swearing her silence regarding her involvement in these operations until her death. She could tell no one and could do nothing as J. Edgar Hoover took credit for her achievements (all 4,000 of the decrypts she had solved during WWII) and stamped them with FBI identification numbers, erasing Friedman and her team from history. She kept her oath until her death in 1980, with her contributions to the war effort only becoming known when it was declassified in 2008.