A method for the provision of a cryptosystem using equivocation augmentation in the encryption and decryption of data, the method comprising: - generating keys at the source node using a first entropy pool initialised with a key shared between the source and a destination node; - encrypting a plaintext message using an XOR and a first key from the first entropy pool to produce a first ciphertext; - encrypting a random sequence using an XOR and a second key from the first entropy pool to produce a second ciphertext; - performing a message equivocation augmentation operation, wherein said operation increases message equivocation H E (M) when an assailant performs a brute force key attack on a third ciphertext, said operation including both an XOR encryption and a subsequent transposition with fixed period encryption taking the joined first and second ciphertexts as inputs and producing a third ciphertext as an output using a third and fourth key derived from the first entropy pool; - transmitting of the third ciphertext from the source node to the destination node; - generating keys at the destination node using a second entropy pool initialised with the key shared between the source and the destination node, wherein the keys are identical to that generated at the source node; - decrypting the third ciphertext at the destination by a reversal of the encryption steps performed at the source node using said identical keys to produce a plaintext message and a random sequence and - performing a key equivocation augmentation operation after every encryption cycle, wherein said operation results in an increase in key equivocation H E (K) after an assailant has performed a brute force key attack on the third ciphertext, said operation including where the random sequence is used to alter the values in the first entropy pool and is used to alter the values in the second entropy pool using a mathematical operation such as modular addition or multiplication. - generating keys at the source node using a first entropy pool initialised with a key shared between the source and a destination node; - encrypting a plaintext message using an XOR and a first key from the first entropy pool to produce a first ciphertext; - encrypting a random sequence using an XOR and a second key from the first entropy pool to produce a second ciphertext; - performing a message equivocation augmentation operation, wherein said operation increases message equivocation H E (M) when an assailant performs a brute force key attack on a third ciphertext, said operation including both an XOR encryption and a subsequent transposition with fixed period encryption taking the joined first and second ciphertexts as inputs and producing a third ciphertext as an output using a third and fourth key derived from the first entropy pool; - transmitting of the third ciphertext from the source node to the destination node; - generating keys at the destination node using a second entropy pool initialised with the key shared between the source and the destination node, wherein the keys are identical to that generated at the source node; - decrypting the third ciphertext at the destination by a reversal of the encryption steps performed at the source node using said identical keys to produce a plaintext message and a random sequence and - performing a key equivocation augmentation operation after every encryption cycle, wherein said operation results in an increase in key equivocation H E (K) after an assailant has performed a brute force key attack on the third ciphertext, said operation including where the random sequence is used to alter the values in the first entropy pool and is used to alter the values in the second entropy pool using a mathematical operation such as modular addition or multiplication. <EOS>