1 An icsa white Paper

Cleartext
Private Key: 7dhHG0(Jd*/89f-0ejf-pt2@...
ENCRYPT
Ciphertext
Ciphertext
Public Key: fu3f93jgf912=kjh#1sdfjdh1&...
DECRYPT
Cleartext
False Key:8f84J3/;#-0=3j@<}...
DECRYPT
Garbage
Ciphertext
Figure 3. How the PKC Protects Confidentiality. 
6.4 Using the PKC to Establish Authenticity 
Similarly, to prove the authenticity and integrity of a message, the sender can encrypt the 
cleartext using the sender's 
private
key; any recipient can verify both the integrity and 
authenticity of the cleartext by decrypting the ciphertext using the 
sender's public key
. If the 
ciphertext can successfully be decrypted using the sender's public key, then only the user of the 
corresponding private key could have created the ciphertext. Figure 4 illustrates the 
demonstration of authenticity using the PKC. 

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Copyright © 1997 M. E. Kabay & ICSA. All rights reserved. Page 31 of 33
Cleartext
Private Key: 7dhHG0(Jd*/89f-0ejf-pt2@...
ENCRYPT
Ciphertext
Ciphertext
Public Key: fu3f93jgf912=kjh#1sdfjdh1&...
DECRYPT
Cleartext
Cleartext
False Key:8f84J3/;#-0=3j@<}...
ENCRYPT
Ciphertext
Ciphertext
Public Key: fu3f93jgf912=kjh#1sdfjdh1&...
DECRYPT
Garbage
 
Figure 4. How the PKC Prevents Forgery