A cryptographic method is described. The method comprises storing binary data representing at least a portion of a field element of an odd-characteristic finite field GF(pk) in a register, p being an odd prime number, the field element comprising k coefficients in accordance with a polynomial-basis representation, the binary data comprising plural groups of data bits, wherein each group of data bits represents an associated one of the k coefficients and processing the binary data in accordance with a cryptographic algorithm such that the plural groups of data bits are processed in parallel. An apparatus comprising a memory and a processing unit coupled to the memory to carry out the method is also described.