Host systems are used in hybrid decryption environments to decrypt account data for the purpose of processing payments. A Host system is a computer or other device that is not considered a secure cryptographic device (SCD). In the context of the P2PE standard, the Host system is defined as a combination of software and hardware components used for the purpose of decrypting account data. Host systems may also be used for transaction processing.
Characteristics of a Host system include:

• Host systems are notsecure cryptographic devices (SCDs)
• Host systems perform decryption of account data
• Host systems temporarily retain data decryption keys (DDKs) in volatile memory.
• Host systems do not perform key generation, key loading, key injection or key distribution functions ? these must be performed by an HSM or other SCD
• Host systems do not share, output or transmit any cryptographic key (either encrypted or in clear text) to any process, application or system outside of the transaction processing function