A system comprising: an object; a portable electronic device; and a backend device, wherein the backend device is configured to, upon occurrence of a triggering event, generate a first virtual key and transmit the first virtual key to the portable electronic device, and generate a corresponding second virtual key and transmit the second virtual key to the object, wherein the object is configured to enable at least one function of the object if the portable electronic device is detected within a predefined distance from the object and the first virtual key and the second virtual key are determined to be valid and to correspond to each other, the backend device is configured to generate the first virtual key and the second virtual key after verifying that the portable electronic device and the object are both registered within the backend device, characterised in that, the portable electronic device comprises a first pair of cryptographic keys (61, 63), the first pair of cryptographic keys (61, 63) comprising a first private key and a first public key, wherein the portable electronic device is configured to transmit the first public key to the backend device, and wherein the portable electronic device is verified as being registered within the backend device if the first public key is stored within the backend device; and the object comprises a second pair of cryptographic keys (62, 64), the second pair of cryptographic keys (62, 64) comprising a second private key and a second public key, wherein the object is configured to transmit the second public key to the backend device, and wherein the object is verified as being registered within the backend device if the second public key is stored within the backend device. an object; a portable electronic device; and a backend device, wherein the backend device is configured to, upon occurrence of a triggering event, generate a first virtual key and transmit the first virtual key to the portable electronic device, and generate a corresponding second virtual key and transmit the second virtual key to the object, wherein the object is configured to enable at least one function of the object if the portable electronic device is detected within a predefined distance from the object and the first virtual key and the second virtual key are determined to be valid and to correspond to each other, the backend device is configured to generate the first virtual key and the second virtual key after verifying that the portable electronic device and the object are both registered within the backend device, characterised in that, the portable electronic device comprises a first pair of cryptographic keys (61, 63), the first pair of cryptographic keys (61, 63) comprising a first private key and a first public key, wherein the portable electronic device is configured to transmit the first public key to the backend device, and wherein the portable electronic device is verified as being registered within the backend device if the first public key is stored within the backend device; and the object comprises a second pair of cryptographic keys (62, 64), the second pair of cryptographic keys (62, 64) comprising a second private key and a second public key, wherein the object is configured to transmit the second public key to the backend device, and wherein the object is verified as being registered within the backend device if the second public key is stored within the backend device. upon occurrence of a triggering event, generate a first virtual key and transmit the first virtual key to the portable electronic device, and generate a corresponding second virtual key and transmit the second virtual key to the object, wherein the object is configured to enable at least one function of the object if the portable electronic device is detected within a predefined distance from the object and the first virtual key and the second virtual key are determined to be valid and to correspond to each other, the backend device is configured to generate the first virtual key and the second virtual key after verifying that the portable electronic device and the object are both registered within the backend device, characterised in that, the portable electronic device comprises a first pair of cryptographic keys (61, 63), the first pair of cryptographic keys (61, 63) comprising a first private key and a first public key, wherein the portable electronic device is configured to transmit the first public key to the backend device, and wherein the portable electronic device is verified as being registered within the backend device if the first public key is stored within the backend device; and the object comprises a second pair of cryptographic keys (62, 64), the second pair of cryptographic keys (62, 64) comprising a second private key and a second public key, wherein the object is configured to transmit the second public key to the backend device, and wherein the object is verified as being registered within the backend device if the second public key is stored within the backend device.