The invention is notably directed to a method of processing data in-memory. The method applies electrical signals to at least two input lines, which correspond to at least two rows. These two rows include at least one of the K rows and at least one of the L rows. This causes to obtain output signals in output of the M output lines, wherein the output signals depend on target values and operand values, in accordance with data stored across said at least two rows. Finally, the output signals are read out and a transformation operation is concurrently performed, in-memory, on the target values based on the operand values. This way transformed data are obtained by way of in-memory processing. The transformation may for instance be a cryptographic operation; the operand data may encode a cryptographic key. The invention is further directed to related apparatuses and systems, notably cryptographic service systems.