Signals & Cyber Intelligence

5th century BC · roughly 2,500 years ago

Spartan generals used the scytale to encrypt military messages

A strip of parchment wound around a wooden rod of a specific diameter produced text that was unreadable until wound around a matching rod, among the earliest known devices built specifically for military cryptography.

9th century · roughly 1,200 years ago

The Arab scholar Al-Kindi wrote the first known treatise on breaking ciphers

Working in Abbasid Baghdad, he described frequency analysis, the technique of using how often letters appear in a language to break substitution ciphers, a foundational method of cryptanalysis that remained in use for a thousand years.

1900 · 126 years ago

British forces in the Boer War made the first electronic interceptions of wireless traffic

During the Boer War of 1899–1902 the Royal Navy had Marconi wireless sets aboard ships and the British Army used limited wireless signalling. The Boers captured some sets and used them for vital transmissions, producing the earliest recorded electronic interceptions. Because the British were then the only other transmitters, no special interpretation of signals was needed.

1901 · 125 years ago

Guglielmo Marconi sent the first transatlantic radio transmission

The demonstration that radio signals could cross an ocean created a new medium of long-range communication that, within years, militaries were learning to intercept, opening the field that became known as signals intelligence.

1904 · 122 years ago

HMS Diana intercepted Russian naval mobilisation signals in the Suez Canal

As the Russian fleet prepared for war with Japan, the British ship HMS Diana stationed in the Suez Canal intercepted Russian naval wireless signals ordering the fleet's mobilisation. This is regarded as the first interception of its kind in history and marks the birth of signals intelligence in the modern sense.

1914 · 112 years ago

Britain cut all German undersea cables to force interceptable traffic

On the declaration of war Britain severed Germany's undersea cables, forcing German communications either onto telegraph lines running through the British network, which could be tapped, or onto radio, which could be intercepted. This deliberate shaping of an adversary's communications became a foundational technique of signals intelligence.

1914 · 112 years ago

Rear Admiral Henry Oliver and Sir Alfred Ewing established Room 40 at the Admiralty

Oliver appointed Ewing to create an interception and decryption service at the Admiralty, known as Room 40. Together with the 'Y' service, post office and Marconi stations, the British came to intercept almost all official German messages, building deep national expertise in codebreaking and traffic analysis.

1914 · 112 years ago

German Army under Ludendorff and Hindenburg exploited Russian signals insecurity at Tannenberg

Russia's failure to protect its communications compromised the Russian Army's early advance in the First World War and contributed to its defeat at the Battle of Tannenberg. The episode demonstrated the operational consequences of poor signals security.

1915 · 111 years ago

Captain H.J. Round of Marconi began experiments with direction-finding radio equipment in France

Round's work for the army developed radio-receiving equipment able to pinpoint the location of a single transmitter. By May 1915 the Admiralty could track German submarines crossing the North Sea, and a new section within Room 40 plotted ship positions from directional reports.

1917 · 109 years ago

British naval intelligence's Room 40 decrypted the Zimmermann Telegram

Interception and decryption of a German proposal to Mexico of an anti-American alliance was passed to Washington, helping bring the United States into the First World War and demonstrating the strategic value of signals interception at the highest level of policy.

1918 · 108 years ago

Georges Painvin cryptanalysed the ADFGVX cipher

French intercept personnel captured a message in the new German ADFGVX cipher, which Painvin broke. This gave the Allies advance warning of the German 1918 Spring Offensive.

1919 · 107 years ago

British Cabinet's Secret Service Committee under Lord Curzon recommended a peace-time codebreaking agency

With the value of interception and decryption established by wartime experience, the committee recommended creating a permanent codebreaking body. This led directly to the institutionalisation of SIGINT in peacetime.

1919 · 107 years ago

Government Code and Cypher School formed as the world's first peace-time codebreaking agency

GC&CS officially formed on 1 November 1919 with a public role advising on government code security and a secret directive to study foreign powers' cypher communications; it produced its first decrypt on 19 October. By 1940 it was working on the diplomatic codes and ciphers of 26 countries and over 150 cryptosystems.

1919 · 107 years ago

United States established the Cipher Bureau

The US Cipher Bureau was created in 1919 and achieved success at the Washington Naval Conference in 1921 through Herbert Yardley's cryptanalysis. It gave the United States its first standing peacetime signals intelligence capability.

1929 · 97 years ago

Secretary of War Henry L. Stimson closed the US Cipher Bureau

Stimson shut the bureau with the words "Gentlemen do not read each other's mail". The closure interrupted American institutional SIGINT capacity in the interwar period.

1941 · 85 years ago

British and Polish codebreakers broke the German Enigma cipher at Bletchley Park

British codebreakers at the Government Code and Cypher School, Bletchley Park, industrialised the breaking of German machine ciphers under the code name Ultra. Building on earlier Polish reconstruction of the Enigma machine, and exploiting flaws in German cryptographic procedure and poor operator discipline, cryptanalysts attacked the theoretically unbreakable Enigma and Lorenz ciphers. Ultra proved essential in the Battle of the Atlantic and at Cape Matapan and North Cape, and is credited by intelligence historians with shortening the war; it established the template for state-scale, machine-assisted codebreaking.

• The Colossus computer began breaking higher-level German cipher traffic

1941 · 85 years ago

Ultra shaped the North African desert campaign against Rommel

Ultra exerted a powerful effect on operations against German forces under Rommel, with General Auchinleck writing that without it "Rommel would have certainly got through to Cairo". Ultra decrypts also featured in Operation SALAM in 1942.

1941–42 · 85 years ago

German SIGINT company in North Africa was destroyed by Australian raiders

German cryptanalysis, direction finding and traffic analysis were vital to Rommel's early successes in the Western Desert Campaign. British forces then tightened communications discipline and Australian raiders destroyed his principal SIGINT company, removing the advantage.

2025 · last year

A hacktivist group associated with Israel claimed disruptive attacks on Iranian financial institutions

During the direct conflict between Israel and Iran, a group with a history of claiming attacks on Iranian industrial and financial targets said it had disrupted operations at a bank and a cryptocurrency exchange, though the claims were not independently verified in full.

Early 2025 · last year

NATO launched the Baltic Sentry mission after a spate of undersea cable damage

A series of incidents in which power and data cables beneath the Baltic Sea were severed, several linked to vessels associated with Russia's shadow fleet, prompted an enhanced naval and surveillance presence to protect undersea infrastructure that also carries signals traffic.

2024 · 2 years ago

An Iran-linked group known as CyberAv3ngers targeted water utilities and industrial control systems in the US and Europe

The group exploited internet-exposed programmable logic controllers made by an Israeli manufacturer to deface control panels and disrupt small utilities, part of a pattern of politically motivated intrusions against industrial control systems tied to Israeli technology.

2024–2025 · in the past two years

The UK and France led a growing coalition against the proliferation of commercial spyware

The Pall Mall Process brought together dozens of states and companies to agree principles limiting the sale and misuse of commercial hacking and surveillance tools, responding to scandals involving spyware used against journalists, officials and dissidents.

• Spyware makers faced new export and sanctions restrictions

2024–2025 · in the past two years

The UK's National Cyber Force grew as it consolidated operations at a new headquarters

The joint military and intelligence organisation responsible for the UK's offensive cyber operations continued expanding staff numbers and moved toward full operating capability at a dedicated site, part of a broader growth in publicly avowed offensive cyber capacity among allied states.

2024–2025 · in the past two years

North Korea's Kimsuky group ran cyber espionage campaigns against South Korean and US targets

Phishing and malware campaigns targeted researchers, officials and defence-linked organisations working on nuclear and foreign policy issues, part of a long-running intelligence-collection effort distinct from the regime's separate financially motivated hacking operations.

2024–2025 · in the past two years

Australia continued implementing the REDSPICE programme to expand its signals and cyber capacity

Investment under the multi-year plan went toward growing the Australian Signals Directorate's offensive and defensive cyber capabilities and its regional intelligence-sharing role, reflecting a broader push by Canberra to expand technical intelligence capacity alongside its allies.

2024–2025 · in the past two years

China extended its quantum key distribution network linking major cities

Ground-based fibre links and satellite relays extended a communications network designed to resist future code-breaking by quantum computers, part of a wider effort to harden state and military communications against interception.

2024–2025 · in the past two years

Russia's Sandworm unit continued destructive cyber operations against Ukrainian and allied infrastructure

The military intelligence-linked group was tied to intrusions against Ukrainian energy and government systems and to disruptive incidents affecting logistics and infrastructure operators in NATO states supporting Ukraine, according to Western cyber agencies.

• Western cyber agencies issued joint advisories describing the group's methods

Late 2024 · 2 years ago

Chinese state-linked hackers breached major US telecommunications carriers in a campaign known as Salt Typhoon

Intruders gained access to systems used to fulfil lawful wiretap requests and reportedly reached call records and communications tied to senior political figures, prompting emergency meetings between the US government and telecom providers and renewed scrutiny of network security requirements.

• Taiwan reported a continued high volume of Chinese intrusion attempts

2013 · 13 years ago

Edward Snowden disclosed the scale of NSA and Five Eyes global surveillance programmes

Leaked documents revealed bulk collection of communications metadata and direct access arrangements with major technology companies, triggering a global debate over the balance between signals intelligence collection and privacy that reshaped oversight law in several countries.

2010 · 16 years ago

Stuxnet sabotaged centrifuges at Iran's Natanz enrichment facility

A computer worm, widely attributed to US and Israeli intelligence, caused physical damage to industrial equipment through code alone, demonstrating that cyber intrusion could achieve effects previously requiring sabotage or air strikes and opening a new domain of state cyber operations.

late 1990s · 36 years ago

United States developed the PSTS targeting system for interceptors

PSTS constantly transmits information that helps interception operators aim antennas and tune receivers correctly. It illustrates the automation of collection management shared across SIGINT branches, alongside platforms such as the EP-3, RC-135 and ground-directed RC-12 GUARDRAIL.

1978 · 48 years ago

The United States enacted the Foreign Intelligence Surveillance Act

Passed after Senate hearings exposed domestic abuses of signals intelligence collection, the law created a specialised court to authorise surveillance of foreign intelligence targets, establishing a legal framework later copied in modified form by other democracies.

1952 · 74 years ago

The United States established the National Security Agency

A classified presidential directive consolidated code-making and code-breaking functions scattered across the military services into a single agency, centralising American signals intelligence under one roof for the first time.

1946 · 80 years ago

The UK and the US signed the UKUSA Agreement

A secret pact to share signals intelligence and cooperate on collection, later joined by Canada, Australia and New Zealand, created the alliance that became known as Five Eyes and has remained the closest intelligence-sharing relationship among sovereign states.

• The alliance was later reported to run a global system called ECHELON

1944 · 82 years ago

Allied commanders knew nearly all German Western Front divisions before D-Day

Prior to the Normandy landings in June 1944 the Allies knew the locations of all but two of Germany's fifty-eight Western Front divisions. Eisenhower later described Ultra as decisive to Allied victory, and Harry Hinsley judged it shortened the war by at least two years.