TheCodeBreakers
disposition of artillery along Iran's Russian border, two notebooks in
what were obviously cipher, and another with page after page of what
appeared to be trigonometric equations, replete with the Greek letters
beloved of mathematicians and the abbreviations for "secant," "cosine,"
"tangent," and "cotangent." The problem was that mathematically the
formulas made no sense at all.
Colonel Mostafa Amjadi, chief of the intelligence directorate of the
Teheran military governate, and another colonel in the Iranian Army
went to work on the three notebooks. By August 30, they had cracked
the two overt codes, but extracted only meager information from them.
Meanwhile, Abbasi decided to talk. He revealed that the Tudeh party had
riddled the Iranian Army with about 400 agents and that their names
were listed in a mathematical cipher. This was the trigonometric system
which Amjadi and his colleague were even then struggling with, but
annaabi.ee 
