00291nam a2200109 a 450000500170000002000150001708200200003210000250005224500570007726000260013430000210016020251203110109.0  a0486200973  a005.82,D,gaib_  aGaines, Helen Fouche  aCryptanalysisba study of ciphers and their solution  aNew YorkbDoverc1958  avi,237p.c23 cm.