A new image encryption algorithm and its VLSI architecture

On the security of an image encryption method

“…The selection of α, β is not mentioned in [1]. We find α, β must yield the following three restrictions to avoid possible insecurity, the number of such values is only 7 × 7 − 7 − 2 = 40, which is dramatically small and will be useful for cryptanalysis.…”

“…The authors of [1] claim that BRIE needs very low computation complexity, and has high security since {b(i)} contains M N + 1 secure bits generated by the chaotic iterations. However, we will point out that some serious defects exist in BRIE, and that a known/chosen-plaintext attack can break it.…”

“…If there are too many such pixels, the plainimage will roughly emerge from the cipher-image. The plainpixels can be divided into the following four classes 1 . C1) 0, 255: f (x, y) ≡ f (x, y), ∀α, β. C2) 85, 170: If α mod 2 = 0, f (x, y) = f (x, y) when q = α; if α + β mod 2 = 0, f (x, y) = f (x, y) when q = α + β; and if α mod 2 = (α + β) mod 2 = 0,…”

“…Furthermore, special and reliable security in storage and transmission of digital images is needed in many applications, such as pay-TV, medical imaging systems, military image communications and confidential video conferencing, etc. In order to fulfill such a task, many image encryption methods have been proposed [1][2][3][4][5][6][7], but some of them [2,6,7] have been known to be insecure [3,8,9].…”

“…In [1], a novel image encryption method called BRIE (Bit Recirculation Image Encryption) is proposed, which is a pixel transformation cipher. This paper points out some security defects in BRIE, and presents a known/chose-plaintext attack to break BRIE with only one known/chosen plain-image.…”