In RSA, it is desirable to select a small encryption exponent, "e", in order to improve the efficiency of encryption. However, a small encryption exponent should not be used if the same message is sent to many entities, because an eavesdropper can recover the plaintext "m", without knowing the private key, "k" Explain how the eavesdropper can recover the plaintext "m".

Describe a practical countermeasure for thwarting the attack described above, assuming that a small encryption exponent is used and the sender needs to send the same message to many entities.