Release 10.1A: OpenEdge Getting Started:
Core Business Services

> ## Encryption/decryption algorithms

> The encryption/decryption algorithms vary in complexity and speed and rely on iterative applications of Exclusive OR (XOR) on various combinations of key and data. This range of complexity and speed make symmetric key algorithms a common choice for providing data privacy and authentication services. Three common algorithms, listed in increasing order of strength, are:

> 1. Data Encryption Standard (DES).

> 2. Triple DES (DES3).

> 3. Advanced Encryption Standard (AES).

> The same three algorithms listed in generally increasing order of speed are:

> 1. DES3

> 2. DES

> 3. AES

> Variations of these algorithms exist. One of them, AES, supports different key sizes, such as 128 or 256 bits. Variations also exist for different modes of operation (modes). A mode is a kind of companion algorithm that tailors the symmetric-key algorithm for different applications, such as confidentiality or authentication. For example, one of several confidentiality modes is CBC.

> In the Progress 4GL, symmetric-key algorithms are identified by the three components of their supported variations: `algorithm``_``mode``_``keysize`. So, for example, one of the supported symmetric-key algorithms is identified by the string `"AES_CBC_128"`, which specifies the AES symmetric-key algorithm combined with the CBC mode using a 128-bit key size.

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