Also referred to as conventional encryption, secret-key, or ...

[cherise1989]

Also referred to as conventional encryption, secret-key, or single-key encryption, _________ encryption was the only type of encryption in use prior to the development of public-key encryption in the late 1970's.
 
  What will be an ideal response?

Question 2

Many symmetric block encryption algorithms including DES have a structure first described by _________ of IBM in 1973.
 
  What will be an ideal response?

[mcomstock09]

Answer to Question 1

SYMMETRIC

Answer to Question 2

HORST FEISTEL

[cherise1989]

Thanks for the timely response, appreciate it

[zacnyjessica]

Gracias!