Common Data Security Architecture (CDSA) White Paper

Chapter 1 23
Common Data Security Architecture (CDSA) White Paper
Cryptography Service Provider (CSP) API
Figure 1-6 Symmetric Key Algorithm
Authenticating a Digital Signature
When B receives the data, B can be certain only of having received it from someone who used
B’s public key to encrypt it. If B wanted to authenticate the message (that is, make sure that
it was A who sent it), B would have to authenticate a digital signature that A would send with
A’s data. This is shown in Figure 1-7, “Authenticating a Digital Signature.”
[1] Before encrypting data with a symmetric key algorithm, A hashes the data. This creates a
A:
[1]
[2]
RC2 or RC4
symmetric key algorithm
B
A:
[3]
B:
[4]
B:
symmetric key
symmetric key
symmetric key
symmetric key
symmetric key
A’s data
A’s data A’s encrypted data
A’s encrypted data
encrypted symmetric key
encrypted symmetric keyB’s public key
B
B’s private key
B