### Supported Encryption Types

Any tag in the configuration files which requires a list of encryption types can be set to some combination of the following strings.

`des-cbc-crc`
  DES cbc mode with CRC-32
`des-cbc-md4`
  DES cbc mode with RSA-MD4
`des-cbc-md5`
  DES cbc mode with RSA-MD5
`des3-cbc-sha1`
`des3-hmac-sha1`
`des3-cbc-sha1-kd`
  triple DES cbc mode with HMAC/sha1
`des-hmac-sha1`
  DES with HMAC/sha1
`aes256-cts-hmac-sha1-96`
`aes256-cts`
  AES-256 CTS mode with 96-bit SHA-1 HMAC
`aes128-cts-hmac-sha1-96`
`aes128-cts`
  AES-128 CTS mode with 96-bit SHA-1 HMAC
`arcfour-hmac`
`rc4-hmac`
`arcfour-hmac-md5`
  RC4 with HMAC/MD5
`arcfour-hmac-exp`
`rc4-hmac-exp`
`arcfour-hmac-md5-exp`
  exportable RC4 with HMAC/MD5

While aes128-cts and aes256-cts are supported for all Kerberos operations, they are not supported by the GSSAPI. AES GSSAPI support will be added after the necessary standardization work is completed.

By default, AES is enabled on clients and application servers. Because of the lack of support for GSSAPI, AES is disabled in the default KDC supported_enctypes kdc.conf. Sites wishing to use AES encryption types on their KDCs need to be careful not to give GSSAPI services AES keys. If GSSAPI services are given AES keys, then services will start to fail in the future when clients supporting AES for GSSAPI are deployed before updated servers that support AES for GSSAPI. Sites may wish to use AES for user keys and for the ticket granting ticket key, although doing so requires specifying what encryption types are used as each principal is created. Alternatively sites can use the default configuration which will make AES support available in clients and servers but not actually use this support until a future version of Kerberos adds support to GSSAPI.