Decoding the IRA

Decoding the IRA

Without the Army Ireland cannot gain her freedom

Frank Aiken referring to the IRA, 1925

TOM MAHON & JAMES J. GILLOGLY

M
ERCIER
P
RESS
Cork
www.mercierpress.ie

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CMD BookSource,
55a Spruce Avenue, Stillorgan Industrial Park,
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© Tom Mahon & James J. Gillogly, 2008

ISBN: 978 1 85635 697 8
10 9 8 7 6 5 4 3 2 1

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Contents

Key Characters

Introduction

Chapter 1: Breaking the Ciphers

Chapter 2: The IRA's system of communications

Chapter 3: A New Leadership: 1926–1927

Chapter 4: The IRA's local units

Chapter 5: Intelligence

Chapter 6: The IRA in Britain

Chapter 7: The IRA in America

Chapter 8: The Soviet Union and China

Conclusion

Epilogue

Appendix 1: Organisations, groups and technical terms

Appendix 2: The Mystery Woman

Notes

Bibliography

Acknowledgements

Other Interesting Books

D
EDICATION

This book is dedicated to my sister Rosemary and mother Mary In memory of Tom Crofts and his comrades of Cork 1 Brigade

Tom Mahon

To the late William G. Sutton, my long-time cryptographic collaborator and friend, who was always ready to test and suggest new approaches as I developed the cryptanalytic tools I used to break these ciphers.

Jim Gillogly

Key Characters

Aiken, Frank
: IRA chief of staff, April 1923 to November 1925. He supported Éamon de Valera and was a founder member of Fianna Fáil in 1926.

Cooney, Andy:
also known as ‘Mr Smith'. IRA chief of staff from November 1925 to spring 1926, and chairman of the Army Council from November 1925 to January 1927.

de Valera, Éamon:
president of Sinn Féin and of the shadow republican ‘government'. In early 1926 he resigned from both positions and founded Fianna Fáil.

Devoy, John:
veteran Irish-American ‘Fenian' leader, who supported the Free State and opposed both de Valera and the IRA.

George:
also known as ‘HS'. IRA Officer Commanding in Britain from the autumn of 1926 through 1927. Worked closely with the Soviet agent ‘James'. He was likely George Power, an IRA intelligence officer originally from Cork.

James:
pseudonym for a Red Army intelligence agent in London. The IRA supplied him with information in return for payment.

Jones, Mr:
pseudonym, also known as JB. An IRA secret agent in New York, who worked for Soviet intelligence.

Lynch, Liam:
IRA chief of staff during the Civil War, from 1922 until his death in April 1923. Moss Twomey's mentor.

MacBride, Seán:
also known as ‘Mr Ambrose'. An IRA leader closely allied with Moss Twomey. He travelled extensively on the continent, where he was in contact with Soviet agents.

McGarrity, Joseph (Joe):
chairman of Clan na Gael. The most important IRA supporter in America.

Neenan, Connie:
also known as An Timthire. The official IRA representative in the US.

O'Donnell, Peadar:
member of the Army Council and editor of the IRA's paper,
An Phoblacht.
He was the leading IRA republican socialist intellectual and also a distinguished novelist.

Russell, Seán:
IRA quartermaster general, in charge of weapons and explosives. He was the leading militarist in the organisation and was dismissive of any political involvement by the IRA.

Sheehy, John Joe:
captain of the Kerry football team and commander of the Kerry IRA.

Stephen:
pseudonym for the Red Army intelligence agent in America who was in contact with the IRA.

Twomey, Maurice (Moss):
also known as ‘Mr Browne'. Succeeded Andy Cooney as chief of staff in the spring of 1926 and in January 1927 was also appointed chairman of the Army Council. He remained chief of staff until 1936 and was one of the most influential of the IRA's leaders.

N
OTE:

The text which was originally in the IRA's secret code or cipher, is printed in a typewriter type font. For example:
Let me know [the] names of [the] prison officials against whom action should be taken.


Introduction

Tom Mahon

Try and get formulae for these tear gases and mustard gases and [an] idea of [the] plant necessary [for production].

IRA chief of staff to agent in America

Could you get some mines or incendiary bombs put on ships or put ships on fire with petrol or other inflammables?

Moss Twomey, IRA chief of staff, to the IRA in Liverpool

In 2001 I was researching a (still unfinished) project at the University College, Dublin (UCD) Archives when I came across a number of IRA documents from the 1920s that were written in a secret cipher or code. At the time, I didn't think much about them and continued with my research, but every now and then I'd find another such document and slowly my curiosity grew. Eventually, three years later I started to gather them together (with the help of the principal archivist Seamus Helferty and his staff) and set out to have them decrypted. I eventually met up with James Gillogly, one of the leading civilian cryptologists in the world, and this book is the result of James' decryptions of these documents – a world of espionage and intrigue never before described.

This is the IRA for the first time, in its own uncensored words – no topic is omitted and there is no attempt to present a sanitised image for public consumption. This is the complete IRA network – operations, arms smuggling, disputes and retaliation. A story with spies, Russian agents, clandestine meetings and poison gas – it is part James Bond and part Walter Mitty. The tenor of the documents ranges from ruthlessness to pathos and often with a dash of humour. The strength and ingenuity of the IRA is revealed alongside its incompetence and the widespread demoralisation of its members.

In all James decrypted 312 documents written in cipher. The IRA encrypted them so they would remain secret to all except the intended
recipients and they were concerned about seizure by the police. To the best of my knowledge, they have never before been decrypted for publication.

I found the documents among the tens of thousands of papers donated to UCD by the family of Moss Twomey, IRA chief of staff from 1926 to 1936. The encrypted documents represent the most highly classified correspondence between the IRA's General Headquarters (GHQ) in Dublin and its units and operatives. These include units throughout Ireland and Britain, prisoners in jail in Ireland and agents in Britain and America. Some of them contain only a name or address in cipher, others have several pages of densely typed secret text. The despatches to America are the longest, as Moss Twomey had no other way to keep in contact with his representatives there. The vast majority of these documents were dated 1926 or 1927, with a few from either 1925 or 1928.

The cipher is easy to distinguish from ordinary English (or plain text) – frequently consisting of blocks of five letters with no overt meaning. For example, Moss Twomey sent a message to the IRA in Liverpool:
UEIRS, NRFCO, OBISE, IOMRO, POTNE, NANRT, HLYME, PPROM, TERSI, HEELT, NBOFO, LUMDT, TWOAO, ENUUE, RMDIO, SRILA, SSYHP, PRSGI, IOSIT, B.
When decrypted this read:
Could you get some mines or incendiary bombs put on ships or put ships on fire with petrol or other inflammables?
¹

This order was written in 1927, but was dated 1924. This was deliberately done to confuse the police in the event of capture of the document.

T
HE MAJORITY OF THE
documents were written in a transposition cipher, meaning that the individual letters of the original (plain text) message were rearranged. A significant minority of the documents used a substitution cipher, where letters were replaced by assigned letters or symbols. A cipher is different from a true code where the original text is replaced by assigned words, phrases or sentences rather than by individual letters.
²
When I first rounded up samples of the documents and brought them back to my home in Hawaii, there were two questions on my mind. Could they be decrypted? What story would they tell? It seemed to me that a cipher dating from before the time of the German Enigma cipher machines
of the 1930s and 1940s could be broken. But at the time I had no appreciation of the challenges that decryption would present.

Figure 1. Moss Twomey wrote to the OC of the IRA's Liverpool company:
Your intelligence officer reports shipments from there for China. If you can do your utmost to destroy any ammunition or other armament or stores being sent. Could you get some time mines or incendiary bombs put on ships or put ships on fire with petrol or other inflammables? Keep this absolutely secret. Do not discuss it. Either carry out the operations or say nothing about it.


 

When the ciphers were composed, they were encrypted by the sender and then decrypted by the recipient, both of whom possessed a common secret word or keyword (also known as the key). The keyword was any agreed word of moderate length such as ‘imprisonment' or ‘determination'. In most cases, the keywords were no longer known and even if I had the original keyword, I did not know how the cipher was constructed around the key.