Images used as a stochastic signal are among the most commonly used types of information. Accordingly, the actual task is to protect such images from unauthorized access and use. This leads to the use of known classic encryption methods in the case of image encryption. Offered algorithms of encryption-decryption are intended for the use of images in grayscale and are based on using the ideas of basic RSA algorithm. Encryption – decryption can be carried out with extra noising and without too.