Remarks on el-Gamal encryption Scheme ElGamal encryption scheme is non-deterministic Randomization is introduced to increase the effective size of the plaintext space i.e. one plaintext can map to a large set of possible ciphertexts decrease the effectiveness of chosen-plaintext attack by means of a one-to-many mapping in the encryption process · Efficiency: encryption requires two exponentiation operations exponentiation operations may be very expensive when implemented on some low-power devices e.g. low-end PalmPilots smart cards and sensors message expansion by two-fold Security: depends on the difficulty of solving DLP 1515 Remarks on El-Gamal Encryption Scheme • ElGamal encryption scheme is non-deterministic • Randomization is introduced to – increase the effective size of the plaintext space i.e. one plaintext can map to a large set of possible ciphertexts – decrease the effectiveness of chosen-plaintext attack by means of a one-to-many mapping in the encryption process • Efficiency: – encryption requires two exponentiation operations – exponentiation operations may be very expensive when implemented on some low-power devices. e.g. low-end PalmPilots, smart cards and sensors. – message expansion by two-fold • Security:depends on the difficulty of solving DLP