Contact - Carl Sagan [6]
She built an encrypting machine. It was rudimentary, but it worked. It could take any English- language message and transform it by a simple substitution cipher into something that looked like gibberish. Building a machine that would do the reverse-converting an encrypted message into clear when you didn't know the substitution convention-that was much harder. You could have the machine run through all the possible substitutions (A stands for B, A stands for C, A stands for D…), or you could remember that some letters in English were used more often than others. You could get some idea of the frequency of letters by looking at the sizes of the bins for each letter of type in the print shop next door. "ETAOIN SHRDLU," the boys in print shop would say, giving pretty closely the order of the twelve most frequently used letters in English. In decoding a long message, the letter that was most common probably stood for an E. Certain consonants tended to go together, she discovered; vowels distributed themselves more or less at random. The most common three-letter word in the language was "the." If within a word there was a letter standing between a T and an E, it was almost certainly H. If not, you could bet on R or a vowel. She deduced other rules and spent long hours counting up the frequency of letters in various schoolbooks before she discovered that such frequency tables had already been compiled and published. Her decrypting machine was only for her own enjoyment. She did not use it to convey secret messages to friends. She was unsure to whom she might safely confide these electronic and cryptographic interests; the boys became jittery or boisterous, and the girls looked at her strangely.
* * *
Soldiers of the United States were fighting in a distant place called Vietnam. Every month, it seemed, more young men were being scooped off the street or the farm and packed off the Vietnam. The more she learned about the origins of the war, and the more she listened to the public pronouncements of national leaders, the more outraged she became. The President and the Congress were lying and killing, she thought to herself, and almost everyone else was mutely assenting. The fact that her stepfather embraced official positions on treaty obligations, dominoes, and naked Communist aggression only strengthened her resolve. She began attending meetings and rallies at the college nearby. The people she met there seemed much brighter, friendlier, more alive than her awkward and lusterless high school companions. John Staughton first cautioned her and then forbade her to spend time with college students. They would not respect her, he said. They would take advantage of her. She was pretending to a sophistication she did not have and never would. Her style of dress was deteriorating. Military fatigues were inappropriate for a girl and a travesty, a hypocrisy, for someone who claimed to oppose the American intervention in Southeast Asia.
Beyond pious exhortations to Ellie and Staughton not to "fight," her mother participated little in these discussions. Privately she would plead with Ellie to obey her stepfather, to be "nice." Ellie now suspected Staughton of marrying her mother for her father's life insurance-why else? He certainly showed no signs of loving her-and he was not predisposed to be "nice." One day, in some agitation, her mother asked her to do something for all their sakes: attend Bible