A machine instruction is provided that includes an opcode field to provide an opcode, the opcode to identify a perform pseudorandom number operation, and a register field to be used to identify a register, the register to specify a location in memory of a first operand to be used. The machine instruction is executed, and execution includes for each block of memory of one or more blocks of memory of the first operand, generating a hash value using a 512 bit secure hash technique and at least one seed value of a parameter block of the machine instruction; and storing at least a portion of the generated hash value in a corresponding block of memory of the first operand, the generated hash value being at least a portion of a pseudorandom number.