Paper 2020/030 Original: eprint.iacr.org/2020/030 ↗

K-Cipher: A Low Latency, Bit Length Parameterizable Cipher

Abstract

We present the design of a novel low latency, bit length parameterizable cipher, called the ``K-Cipher''. K-Cipher is particularly useful to applications that need to support ultra low latency encryption at arbitrary ciphertext lengths. We can think of a range of networking, gaming and computing applications that may require encrypting data at unusual block lengths for many different reasons, such as to make space for other unencrypted state values. Furthermore, in modern applications, encryption is typically required to complete inside stringent time frames in order not to affect performance. K-Cipher has been designed to meet these requirements. In the paper we present the K-Cipher design and specification and discuss its security properties. Our analysis indicates that K-Cipher is secure against both known ciphertext, as well as adaptive chosen plaintext adversaries. Finally, we present synthesis results of 32-bit and 64-bit K-Cipher encrypt datapaths. Our results show that the encrypt datapaths can complete in no more than 767 psec, or 3 clocks in 3.9-4.9 GHz frequencies, and are associated with a maximum area requirement of 1875 um^2.