Abstract: Side channel leakage is a serious threat to secure devices.Cryptographic information extraction is possible after examining any one of the various side channels, including electromagnetic.A single bit electromagnetic template attack method to achieve such a purpose is proposed to extract encryption keys from cipher chips performing data encryption standard(DES)by passively monitoring and exploiting unintentional radio frequency(RF)emissions.It is similar to traditional template attacks with three notable exceptions.First,it directly targets the encryption key instead of algorithmic permutations the encryption key.Second,it creates templates for single bit rather than multiple bits.Third,plaintext or ciphertext are not necessary for this method.The results regarding the DES encryption scheme confirms the effectiveness of the method in cryptanalysis.