# A Medical Image Encryption Scheme for Secure Fingerprint-Based Authenticated Transmission
## 2 Related Work  
Traditionally, the images are protected by encryption algorithms that convert the original image into an unknown format, such as a noise-like or texture-like format [20; 21; 22; 23]. In this way, it is evident that sensible information is presented in an unknown format, which leads to several tentative attacks. Digital watermarking enables image encryption with visual meaning by embedding sensitive information into a reference image with full visual meaning [24]. Digital watermarking is a widely used approach to ensuring the confidentiality of medical records and images. However, the transmission of the watermarked media in an insecure channel, such as the Internet, makes the technique less robust, with the possibility of attacks [25]. Watermarking is only a method of reliably embedding and decoding hidden information in a cover work [26], but it does not protect the hidden information. Encryption makes it possible to protect the information transmitted using cryptographic keys. Therefore, hybrid approaches have been proposed using cryptography techniques and watermarking to solve the security issue. In [27], a chaotic sequence has been created by a chaotic logistic system, and it has been used to change the position of each pixel in the binary watermarking image achieved by two-dimensional Discrete Cosine Transform (2D-DCT). In [28], DCT has been combined with log-polar transform (LPT) to obtain robust watermarking for medical images. Subsequently, chaotic encryption and hash functions have been used to compensate for the weaknesses of traditional digital watermarking methods, which are unable to protect the medical image. In [25], the medical image and the sensible text data have been embedded in the sub-band of the cover image achieved by DWT. The obtained watermarked image has been encrypted using chaotic encryption. The security of the cryptographic techniques depends on the secret key used to generate chaotic sequences [29; 30] and, consequently, on secure key management. Biometric data has been used as a cryptographic key or mask to overcome this limit. In [31], the patient's biometric image is used to generate two keys. The first key is used to randomize the medical image, and the other key is used to encrypt the randomized image. The author proposed a new encryption technique based on the parameterized all-phase orthogonal transformation. In [32], the iris is used to generate two spiral phase masks. They are used with the lower-upper decomposition with partial pivoting to encrypt the medical image. In [33], the palmprint is used to generate a palmprint phase mask. The medical image is modulated by the palmprint phase mask, and then Fresnel transform and SVD operations are performed. The SVD is used to generate two different keys for encryption and decryption as well as in an asymmetric cryptosystem. In [34], an encryption method based on the face biometric to generate a chaotic face phase mask following the chaotic standard map [35] has been proposed. The random phase mask is used to encrypt the extracted region of interest (ROI) of the medical image. The ROI of the medical image has been selected and extracted by applying a mask image to the medical image. The mask image has been achieved through the Fuzzy C-Means Clustering (FRFCM) algorithm [36], which clusters the pixels in the original segmented image. The encryption process has been applied after the watermarking process in all proposed hybrid approaches. However, the visual meaning of image encryption has not been realized in this way. In addition, several approaches use biometric data to ensure the authenticity of the image transmitted. [PERSON] et al. [13] have proposed a visual meaning full image encryption to protect the medical image, the patient's electronic health record (EHR), and the doctor's fingerprint to ensure image authenticity. The EHR has been embedded into the original medical image using a watermarking technique to generate a watermarked medical image.