Vernam Cipher

Tags

cryptography

Is a stream cipher which [see page 3, works] by generating a random bitstream (\( B_i \)) and XORing the plaintext input with the stream (bit-by-bit) to produce the ciphertext.

Decryption works by XORing the ciphertext with the original bitstream \( B_i \) in the same way as was done for the encryption. Note: This requires the entirety of \( B_i \) to be available to the recipient.

Note: If the random-stream is truly random then OTP is truly secure (by shannons-theorem).