Forward Secrecy (FS), also known as Perfect Forward Secrecy (PFS), ensures that session keys used for encrypted communications are not compromised even if the long-term server private key is leaked. This is accomplished by generating unique, **ephemeral session keys** for each session, which are not reused or stored. The **ephemeral nature** of these keys means that they exist only for the duration of a single session, making it impossible for an attacker to decrypt past sessions even if they obtain the long-term private key later. Each session key is generated fresh and discarded after the session ends, reinforcing the security of the communication.

In practice, this means that even if an attacker captures encrypted traffic, they would only have access to the data encrypted with that specific session key. If they later compromise the server’s long-term private key, they would still be unable to decrypt previous sessions, thus protecting sensitive information from retroactive decryption.

**Risks of Not Implementing Forward Secrecy:**

1. **Retroactive Decryption**: Attackers can decrypt historical data if they obtain the private key.  
2. **Increased Attack Surface**: Lack of FS increases exposure to advanced attacks such as those involving compromised private keys.  
3. **Compliance Violations**: Many security standards and regulations recommend the use of Forward Secrecy to safeguard encrypted data.

**Example Scenario:** An attacker who compromises a server's private key could decrypt all previously captured traffic if Forward Secrecy is not enabled. Sensitive data such as login credentials, financial information, or personal data could be exposed.

Failure to implement Forward Secrecy could also impact compliance with security standards like PCI DSS, GDPR, and HIPAA, which emphasize strong encryption and data protection mechanisms.