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NAME

des_modes - the variants of DES and other crypto algorithms of OpenSSL

DESCRIPTION

Several crypto algorithms for OpenSSL can be used in a number of modes. Those are used for using block ciphers in a way similar to stream ciphers, among other things.

OVERVIEW

Electronic Codebook Mode (ECB)

Normally, this is found as the function algorithm_ecb_encrypt().

Cipher Block Chaining Mode (CBC)

Normally, this is found as the function algorithm_cbc_encrypt(). Be aware that des_cbc_encrypt() is not really DES CBC (it does not update the IV); use des_ncbc_encrypt() instead.

Cipher Feedback Mode (CFB)

Normally, this is found as the function algorithm_cfb_encrypt().

Output Feedback Mode (OFB)

Normally, this is found as the function algorithm_ofb_encrypt().

Triple ECB Mode

Normally, this is found as the function algorithm_ecb3_encrypt().

Triple CBC Mode

Normally, this is found as the function algorithm_ede3_cbc_encrypt().

NOTES

This text was been written in large parts by Eric Young in his original documentation for SSLeay, the predecessor of OpenSSL. In turn, he attributed it to:

        AS 2805.5.2
        Australian Standard
        Electronic funds transfer - Requirements for interfaces,
        Part 5.2: Modes of operation for an n-bit block cipher algorithm
        Appendix A

SEE ALSO

blowfish(3), des(3), idea(3), rc2(3)