HP UX Security Products and Features Software manual Symmetric Key Algorithm

Figure 1-5

[1].

A:

Common Data Security Architecture (CDSA) White Paper

Cryptography Service Provider (CSP) API

Dual Asymmetric Key Algorithm

B B

A's data B's public key A's encrypted data

[2]

B:

B

B's private key A's encrypted data A's data

Symmetric Key Algorithm

Because asymmetric key algorithms are very expensive computationally, symmetric key algorithms (which use the same one key to encrypt and decrypt) are used to bulk-encrypt the data. In this example, an asymmetric key algorithm is used to encrypt only the symmetric key.

[1]A chooses a symmetric key algorithm (such as RC2 or RC4) and uses it to generate a symmetric key to bulk-encrypt A’s data.

[2]A then use B’s public key to encrypt the symmetric key. A sends both symmetric key and bulk-encrypted data to B.

[3]B uses B’s private key to decrypt the symmetric key.

[4]B uses the symmetric key to decrypt A’s encrypted data.

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