This European Standard specifies security requirements and recommendations for Trustworthy Systems Supporting Server Signing (TW4S) that generate digital signatures. The TW4S is composed at least of one Server Signing Application (SSA) and one Signature Creation Device (SCDev) or one remote Signature Creation Device. A remote SCDev is a SCDev extended with remote control provided by a Signature Activation Module (SAM) executed in a tamper protected environment. This module uses the Signature Activation Data (SAD), collected through a Signature Activation Protocol (SAP), in order to guarantee with a high level of confidence that the signing keys are used under sole control of the signer. The SSA uses a SCDev or a remote SCDev in order to generate, maintain and use the signing keys under the sole control of their authorized signer. Signing key import from CAs is out of scope. So when the SSA uses a remote SCDev, the authorized signer remotely controls the signing key with a high level of confidence. A TW4S is intended to deliver to the signer or to some other application, a digital signature created based on the data to be signed. This standard: provides commonly recognized functional models of TW4S; specifies overall requirements that apply across all of the services identified in the functional model; specifies security requirements for each of the services identified in the TW4S; specifies security requirements for sensitive system components which may be used by the TW4S. This standard is technology and protocol neutral and focuses on security requirements.