This is a generic solution with a constant size of signature. Once again, the size of the signature is the same as that of the underlying signature scheme. However, the signer has to check the validity of GM signatures for each revoked member which makes his work linear in the number of revoked members. The work of the group manager is constant-size since he only has to add a new value and to compute two signatures at each revocation. The verifier also has a constant-size work. Note that this method can also be used in a context of ``white list''.