Definition - What does Key Escrow mean?
Key escrow is a cryptographic key exchange process in which a key is held in escrow, or stored, by a third party. A key that is lost or compromised by its original user(s) may be used to decrypt encrypted material, allowing restoration of the original material to its unencrypted state.
Techopedia explains Key Escrow
Key escrow systems provide a backup source for cryptographic keys. Escrow systems are somewhat risky because a third party is involved.
The Clipper Chip was a U.S. government encryption chipset introduced in 1993. The chipset was promoted as an encryption device with a government-held (escrow) master key to facilitate encryption in the face of security threats. The controversial Clipper Chip was defunct by 1996, but the concept evolved into the Pretty Good Privacy (PGP) encryption tool, which is used worldwide.