IDEA

https://en.wikipedia.org/wiki/International_Data_Encryption_Algorithm

In cryptography, the International Data Encryption Algorithm (IDEA), originally called Improved

Proposed Encryption Standard (IPES), is a symmetric-key block cipher designed by James Massey of

ETH Zurich and Xuejia Lai and was first described in 1991. The algorithm was intended as a

replacement for the Data Encryption Standard (DES). IDEA is a minor revision of an earlier cipher

Proposed Encryption Standard (PES).

The cipher was designed under a research contract with the Hasler Foundation, which became part

of Ascom-Tech AG. The cipher was patented in a number of countries but was freely available for

non-commercial use. The name "IDEA" is also a trademark. The last patents expired in 2012, and

IDEA is now patent-free and thus completely free for all uses.

IDEA was used in Pretty Good Privacy (PGP) v2.0 and was incorporated after the original cipher used

in v1.0, BassOmatic, was found to be insecure. IDEA is an optional algorithm in the OpenPGP

standard.

Incorrect answers:

CAST - symmetric algorithm. Created in 1996 by Carlisle Adams and Stafford Tavares. Operates on 64

bit blocks and has a key size of 40-128 bits. Typically used in GPG and PGP. Encryption is either 12 or

16 rounds.

DES - The Data Encryption Standard is a symmetric-key algorithm for the encryption of digital data.

Although its short key length of 56 bits makes it too insecure for applications, it has been highly

influential in the advancement of cryptography.

RSA - a public-key cryptosystem that is widely used for secure data transmission. It is also one of the

oldest. The acronym RSA comes from the surnames of Ron Rivest, Adi Shamir, and Leonard Adleman,

who publicly described the algorithm in 1977