An apparatus comprising: one or more processors; and a reconfigurable circuit device, the reconfigurable circuit device including: a dedicated cryptographic hash hardware engine, and a reconfigurable fabric including a plurality of logic elements, LEs; wherein the one or more processors are to configure the reconfigurable circuit device for public key signature operation, including: mapping a state machine for public key generation and verification to the reconfigurable fabric, including mapping one or more cryptographic hash engines to the reconfigurable fabric, and combining the dedicated cryptographic hash hardware engine with the one or more mapped cryptographic hash engines for cryptographic signature generation and verification; wherein the dedicated cryptographic hash hardware engine and the one or more mapped cryptographic hash engines are Secure Hash Algorithm 2, SHA-2, engines; wherein the public key signature operation includes Extended Merkel Signature Scheme, XMSS; wherein the state machine is designed to perform XMSS-specific pre-hash optimizations using the existing SHA-2 engine; characterized in that the state machine includes a controller to control operation of the public key generation and verification; wherein the controller is to schedule hash chains for the public key generation and verification between the dedicated cryptographic hash hardware engine and the one or more mapped cryptographic hash engines based at least in part on resources of the reconfigurable circuit device; wherein the scheduling of hash chains includes one or more of scheduling hash chains based at least in part on a length of each hash chain or hash chains based at least in part on a length of each hash chain. one or more processors; and a reconfigurable circuit device, the reconfigurable circuit device including: a dedicated cryptographic hash hardware engine, and a reconfigurable fabric including a plurality of logic elements, LEs; a dedicated cryptographic hash hardware engine, and a reconfigurable fabric including a plurality of logic elements, LEs; wherein the one or more processors are to configure the reconfigurable circuit device for public key signature operation, including: mapping a state machine for public key generation and verification to the reconfigurable fabric, including mapping one or more cryptographic hash engines to the reconfigurable fabric, and combining the dedicated cryptographic hash hardware engine with the one or more mapped cryptographic hash engines for cryptographic signature generation and verification; wherein the dedicated cryptographic hash hardware engine and the one or more mapped cryptographic hash engines are Secure Hash Algorithm 2, SHA-2, engines; wherein the public key signature operation includes Extended Merkel Signature Scheme, XMSS; wherein the state machine is designed to perform XMSS-specific pre-hash optimizations using the existing SHA-2 engine; characterized in that the state machine includes a controller to control operation of the public key generation and verification; wherein the controller is to schedule hash chains for the public key generation and verification between the dedicated cryptographic hash hardware engine and the one or more mapped cryptographic hash engines based at least in part on resources of the reconfigurable circuit device; wherein the scheduling of hash chains includes one or more of scheduling hash chains based at least in part on a length of each hash chain or hash chains based at least in part on a length of each hash chain. mapping a state machine for public key generation and verification to the reconfigurable fabric, including mapping one or more cryptographic hash engines to the reconfigurable fabric, and combining the dedicated cryptographic hash hardware engine with the one or more mapped cryptographic hash engines for cryptographic signature generation and verification; wherein the dedicated cryptographic hash hardware engine and the one or more mapped cryptographic hash engines are Secure Hash Algorithm 2, SHA-2, engines; wherein the public key signature operation includes Extended Merkel Signature Scheme, XMSS; wherein the state machine is designed to perform XMSS-specific pre-hash optimizations using the existing SHA-2 engine; characterized in that the state machine includes a controller to control operation of the public key generation and verification; wherein the controller is to schedule hash chains for the public key generation and verification between the dedicated cryptographic hash hardware engine and the one or more mapped cryptographic hash engines based at least in part on resources of the reconfigurable circuit device; wherein the scheduling of hash chains includes one or more of scheduling hash chains based at least in part on a length of each hash chain or hash chains based at least in part on a length of each hash chain.