Change the IBM Security Directory Server password encryption

To change the type of encryption using the command line, issue the following command:

idsldapmodify -p port -D  adminDN  -w  adminPW  -i  filename 

where filename contains:

dn: cn=configuration
changetype: modify
replace: ibm-slapdPWEncryption
ibm-slapdPWEncryption:  password_encryption_mechanism 

Here, the ibm-slapdPWEncryption attribute can be assigned any of the 
following values: none,aes128,aes192,aes256,crypt,sha,ssha, md5
sha224, sha256, sha384, sha512, ssha224, ssha256, ssha384, or ssha512.

To cause the updated settings to take effect dynamically, issue the following idsldapexop command:

idsldapexop -D  adminDN  -w  adminPW  -op readconfig -scope single 
        "cn=configuration" ibm-slapdPWEncryption

The information is from Knowledge Center