#### Milestone Year

### 1982

#### Probabilistic encryption and laying rigorous foundations to cryptography

What is a secure encryption system?

Surely, such a system should not allow to extract
the original information (called the plaintext)
from the encrypted form (called a ciphertext).

But is this all?
Not really, since in many applications the extraction
of some partial information (regarding the plaintext)
may be harmful enough. Indeed, this harmful partial information
may vary from application to application.

In 1982, a WIS scientist and her collaborator put forward
a robust definition of security,
which suffices for all possible applications.
Furthermore, they (and subsequent work) showed that
such a robust level of security can be achieved whenever
a minimal level of security can be achieved.
Their encryption scheme uses randomness as part
of the encryption process, which is unavoidable for
the robust definition of security.

The definitional approach underlying their proposal was
adopted in almost all subsequent research in cryptography,
which extends way beyond the domain of encryption
(see Zero-Knowledge, Secure Multi-Party Protocols).

In 2012 this work served as the the basis for the bestowing
of the Turing award on its co-authors.

In general, WIS scientists made numerous important contributions
to the foundations of cryptography.
Notable examples include Pseudorandomness , Zero-Knowledge , and Secure Multi-Party Protocols.