Manpage of SLAPPASSWD
Slappasswd is used to generate an userPassword value suitable for use with ldapmodify(1) or slapd.conf(5) rootpw configuration directive.
Note that scheme names may need to be protected, due to { and }, from expansion by the user's command interpreter.
{SHA} and {SSHA} use the SHA-1 algorithm (FIPS 160-1), the latter with a seed.
{MD5} and {SMD5} use the MD5 algorithm (RFC 1321), the latter with a seed.
{CRYPT} uses the crypt(3).
{CLEARTEXT} indicates that the new password should be added to userPassword as clear text.
"OpenLDAP Administrator's Guide" (http://www.OpenLDAP.org/doc/admin/)