●●●●● ●●●● ●●0 Symmetric Encryption ●●● ●●●● e Also called conventional private-key single-key sender and recipient share a common key o all classical encryption algorithms are private- key o was the only type prior to the invention of public-key in 1970S COMP4690. HKBUCOMP4690, HKBU 4 Symmetric Encryption ⚫ Also called conventional / private-key / single-key ⚫ sender and recipient share a common key ⚫ all classical encryption algorithms are private￾key ⚫ was the only type prior to the invention of public-key in 1970’s