Encryption is becoming a vital process to ensure security over the wireless channel. However, using well-known encryption algorithms to encrypt data in wireless communication results in a catastrophic error because of the avalanche effect, which is an inherited criterion to ensure security. Although this criterion is desirable, these algorithms do not take into account the error characteristics of the wireless channel. Therefore, if an error occurs in the encrypted data over the channel, the decryption process at the receiver results in half the original bits to be in error because of this criterion. Hence, the need for a new secure encryption algorithm that takes into account the error characteristics of the wireless channel becomes necessary. In this paper, we propose a modification to the data encryption standard (DES) to make it secure and immune to errors caused by the wireless channel. We observe that using the modified algorithm in wireless channels improves the bit error rate performance as well as security compared with DES. We consider an additive white Gaussian noise with fading and evaluate the performance of the proposed algorithm in terms of bit error rate. We also show that the proposed algorithm is secure as compared with DES. Copyright © 2014 John Wiley & Sons, Ltd.