'Encrypt a string and return a binary string'

def encrypt(self, plainText, more=None):

    self.bytesToEncrypt += plainText
    (numBlocks, numExtraBytes) = divmod(len(self.bytesToEncrypt), self.blockSize)
    cipherText = ''
    for i in range(numBlocks):
        bStart = (i * self.blockSize)
        ctBlock = self.encryptBlock(self.bytesToEncrypt[bStart:(bStart + self.blockSize)])
        self.encryptBlockCount += 1
        cipherText += ctBlock
    if (numExtraBytes > 0):
        self.bytesToEncrypt = self.bytesToEncrypt[(- numExtraBytes):]
    else:
        self.bytesToEncrypt = ''
    if (more == None):
        finalBytes = self.padding.addPad(self.bytesToEncrypt, self.blockSize)
        if (len(finalBytes) > 0):
            ctBlock = self.encryptBlock(finalBytes)
            self.encryptBlockCount += 1
            cipherText += ctBlock
        self.resetEncrypt()
    return cipherText
