Cited by 4Chaos-based Image/Signal EncryptionCryptographic Implementations and SecurityComputer Science and Engineering

A design of multiple color image encryption scheme based on finite algebraic structures

Open access
Qayyum, Tanveer, Shah, Tariq, Khan, Ilyas, Popa, Ioan-Lucian·2025·Scientific Reports

Abstract

This article introduces an innovative method for constructing substitution and permutation boxes and their application in image encryption. In encryption, the essential component that creates confusion is the substitution box(S-box). S-boxes can be constructed using different mathematical structures. An S-box with high nonlinearity enhances confusion in encryption. The nonlinearity of the S-box depends on its mathematical structure; the more nonlinear the structure, the higher the quality of the S-box. Quality can be measured using differential, linear, and statistical attacks. Another main component in image encryption is the permutation box(P-box), which creates confusion by scrambling the image pixels. The proposed scheme is based on the algebraic structure of the Galois field. In this scheme, we utilize the group action over an 8-bit finite field and then apply a bi-linear transformation to construct S-boxes and P-boxes. The proposed encryption scheme satisfies standard cryptographic requirements. Experimental results show that, in comparison with other well-known existing schemes, the method successfully generates many unique, uncorrelated, and secure S-boxes. A security study of the proposed scheme indicates that multiple color-encrypted images can swiftly and effectively mitigate numerous risks, rendering them suitable for real-time applications with stringent security demands.

AI snapshot

Written from the paper’s full text.

TL;DR

The paper constructs S-boxes and P-boxes over GF(2^8) using group actions, inversion, and linear fractional transformations, then applies them in a multiple color-image encryption scheme with permutation, substitution, and XOR. It reports standard cryptographic metrics near ideal and NIST test passes, claiming suitability for real-time secure image encryption.

Key findings

  • The proposed S-box has nonlinearity 112, SAC average 0.504, LAP max 0.0664, and DAP 0.0234 in Table 2; the text reports BIC values of 0.5000034, 0.49998, and 0.50456, while Table 2 lists BIC average as 112.
  • The encryption scheme reports a key space of 2^240, encrypted-image entropy of 7.9976–7.9987, near-zero correlation values, NPCR above 99.1%, and UACI around 33.1–33.7%.
  • PSNR between plain and ciphered images is 9.38–10.36 dB; under cropping from 5% to 45%, decrypted-image PSNR ranges from 10.36 to 8.23 dB.
  • NIST SP 800-22 tests are reported as passed for a 4×4 image block, and the scheme takes 8 seconds to encrypt an image on a standard PC.

Methods

  • S-box/P-box construction: build GF(2^8) with primitive polynomial \(y^8+y^4+y^3+y^2+1\), apply group actions of GF(2^8) on itself via addition and multiplication, then an inversion map and linear fractional transformation \(\Phi(y)=\frac{a y+b}{c y+d}\) to generate S-boxes and P-boxes.
  • Image encryption: split an RGB image into R, G, and B channels; permute each channel with a P-box; substitute each permuted channel with a separate S-box; XOR with a P-box-generated random sequence; concatenate the encrypted channels. Multiple images are handled as blocks of sizes \(2^n,3^n,\ldots\), including 2×2, 3×3, and 4×4 blocks.
  • Evaluation: standard S-box metrics (NL, LAP, DAP, SAC, BIC), image-security metrics (key space, entropy, histogram, correlation, NPCR/UACI, PSNR, occlusion, computation), and NIST SP 800-22 randomness tests; test images include Butterfly, Baboon, and Peppers at 256×256×3.

Limitations

  • Stated limitations: the paper does not state explicit limitations; it proposes future work in audio/video encryption and hardware implementation.
  • Evident from the text: the key-space arithmetic is inconsistent—each S-P box is said to have \(2^{48}\) configurations, but the total keyspace is written as \((2^{45})^5=2^{240}\) for five boxes.
  • Evident from the text: Table 2 lists BIC average as 112 while the text and Table 6 report BIC values near 0.5; security claims rely on standard statistical tests and comparisons without a formal cryptanalytic proof or broader attack model.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/s41598-025-21018-1

Cites

62 of 62 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

  • Findingreasoning

    The desired S-boxes are from step 5, which exhibits high nonlinearity.

    “The desired S-boxes are from step 5, which exhibits high nonlinearity.”
    Quote in the paperSubstantial claim
  • Findingown data

    The proposed S-boxes satisfy the SAC test.

    “The numerical values indicate that S-boxes satisfy the SAC test.”
    Quote in the paperSubstantial claim
  • Findingown data

    The proposed S-boxes have DAP values closer to the ideal range.

    “The DAP values of the proposed S-boxes are provided in Table 4, showing values closer to the ideal range.”
    Quote in the paperSubstantial claim
  • Findingown data

    The proposed S-box has nonlinearity values of 112 for all eight output bits.

    “| Proposed Scheme | 112 | 112 | 112 | 112 | 112 | 112 | 112 | 112 | 112 |”
    Quote in the paperSubstantial claim
  • Findingown data

    In comparison with other well-known existing schemes, the proposed method successfully generates many unique, uncorrelated, and secure S-boxes.

    “Experimental results show that, in comparison with other well-known existing schemes, the method successfully generates many unique, uncorrelated, and secure S-boxes.”
    Quote in the paperSubstantial claim
  • May combine two claims. 7
  • Classified as probably not a substantial claim. 7
  • May combine two claims.

    Findingown data

    The proposed S-box has a maximum SAC value of 0.545 and a minimum of 0.43.

    “The maximum and minimum values of the suggested S-box are 0.545 and 0.43, respectively.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    The histograms of the ciphered images are substantially different from those of the matching original images, with an essentially uniform distribution.

    “The histograms of the ciphered images are substantially different from those of the matching original images, with an essentially uniform distribution.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingreasoning

    The proposed scheme uses two P-boxes and three S-boxes, and the total keyspace is 2^240.

    “We used two P-boxes and three S-boxes in the entire proposed scheme, so the total keyspace is (2^{45})^5=2^{240}.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    A security study of the proposed scheme indicates that multiple color-encrypted images can swiftly and effectively mitigate numerous risks, rendering them suitable for real-time applications with stringent security demands.

    “A security study of the proposed scheme indicates that multiple color-encrypted images can swiftly and effectively mitigate numerous risks, rendering them suitable for real-time applications with stringent security demands.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given

    To ensure the resistance and cryptographic strength of the proposed S-boxes, S-boxes undergo numerous cryptographic analyses.

    “To ensure the resistance and cryptographic strength of the proposed S-boxes, S-boxes undergo numerous cryptographic analyses that are explained in detail in the following sections (Table 2).”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning

    The suggested technique is distinctive as it treats Galois fields (GF) as a group and operates on GF independently.

    “The suggested technique is distinctive as it treats Galois fields (GF) as a group and operates on GF independently.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationown data

    The proposed S-box is resistant to linear attacks, as demonstrated by its LAP value in Table 2.

    “Table 2 provides the LAP value of the suggested scheme along with a comparison to other published studies, demonstrating the proposed S-box’s resistance to linear attacks.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    The group action of GF(2^8) on itself through addition and multiplication represents a linear transformation.

    “The group action of GF(2^{8}) on itself through addition and multiplication represents a linear transformation.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    The recommended image encryption technique ensures the secure transfer of digital images.

    “The recommended image encryption technique ensures the secure transfer of digital images.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    The confusion component of the proposed scheme enhanced the security of the multiple images.

    “The confusion component of the scheme enhanced the security of the multiple images.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationown data

    The proposed scheme withstands various attacks, including key space analysis, differential attacks, linear attacks, and statistical attacks.

    “The proposed scheme withstands various attacks, including key space analysis, differential attacks, linear attacks, and statistical attacks.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: NPCR and UACI are valid metrics for assessing resistance to differential attacks in image encryption.
    • Rests on an assumption: PSNR is a valid metric for assessing image quality and security in image encryption.
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    The suggested method can encrypt images containing any type of digital data.

    “The suggested method can encrypt images containing any type of digital data.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning

    The suggested scheme should take less time on more advanced systems.

    “it should take less time on more advanced systems.”
    Quote in the paperNot a substantial claim
13 of 13
  • The paper relies on this without support.

    Existing multiple-image encryption techniques solely rely on chaotic structures and encrypt grayscale images.

    “The numerous existing multiple-image encryption techniques, which solely rely on chaotic structures, encrypt grayscale images.”
  • The paper relies on this without support.

    The nonlinearity of an S-box depends on its mathematical structure; the more nonlinear the structure, the higher the quality of the S-box.

    “The nonlinearity of the S-box depends on its mathematical structure; the more nonlinear the structure, the higher the quality of the S-box.”
  • The paper relies on this without support.

    An S-box with high nonlinearity enhances confusion in encryption.

    “An S-box with high nonlinearity enhances confusion in encryption.”
  • The paper relies on this without support.

    The optimal nonlinearity value for an S-box is 120 over GF(2^8).

    “For an S-box, the optimal nonlinearity value is 120 over GF(2^{8}).”
  • The paper relies on this without support.

    Existing image encryption methods that encrypt only one image approximate the original image rather than exactly recovering it, resulting in poor image quality.

    “The drawback of these methods is that, instead of providing a mathematically exact recovery, the reconstruction approach theoretically approximates the original image, resulting in poor image quality.”
  • The paper relies on this without support.

    The random iterative method requires a high number of projections, which increases imaging time.

    “Specifically, the random iterative method necessitates a high number of projections, which increases the imaging time.”
  • The paper relies on this without support.

    NPCR and UACI are valid metrics for assessing resistance to differential attacks in image encryption.

    “The NPCR (Normalized Pixel Change Rate) and UACI (Unified Average Changing Intensity) are important metrics for evaluating image encryption techniques.”
  • The paper relies on this without support.

    PSNR is a valid metric for assessing image quality and security in image encryption.

    “Peak Signal-to-Noise Ratio (PSNR) is a commonly used metric in data compression and transmission to assess the quality of encrypted or reconstructed images.”
  • The paper relies on this without support.

    The test images (Baboon, Pepper, Butterfly, Block of 4x4) are representative for evaluating the proposed scheme's security.

    “While conducting all of the NIST tests, we used the ciphered Baboon 24-bit digital image.”
  • The paper relies on this without support.

    The standard PC used for timing is representative of typical hardware for real-time applications.

    “Moreover, the suggested scheme takes 8 seconds to encrypt the image on a standard PC; it should take less time on more advanced systems.”
  • The paper relies on this without support.

    The comparison with existing methods in Tables 9 and 10 is fair and uses equivalent conditions.

    “Table 9 Comparison of NPCR and UACI Metrics Between the Proposed Scheme and Existing Methods.”
11 of 11

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Total key-space exponent is miscalculated

    Major

    Five boxes with 2^45 configurations each give (2^45)^5 = 2^225, not 2^240. The preceding description instead assigns 2^48 configurations to each box, which would yield 2^240.

    Reported 240 · recomputed 225

  • Claim of lower differential probability conflicts with comparison table

    Major

    The paper says the proposed S-boxes have lower DAP values than published alternatives. Table 2 gives the proposed scheme 0.0234, higher than the AES value of 0.0156.

  • Stated maximum SAC is below a tabulated value

    Minor

    The text gives a maximum SAC of 0.545, but Table 5 includes 0.562500.

  • Optical-encryption citation points to different authors

    Minor

    The text attributes the cited optical multiple-image method to Gao et al., while reference 28 lists Sahasrabuddhe and Laiphrakpam and describes a 3D-scrambling method.

  • Stated minimum SAC is below every tabulated value

    Minor

    The text gives a minimum SAC of 0.43, whereas the lowest value in Table 5 is 0.453125.

  • Citation 25 does not name Zhang et al.

    Minor

    The description attributes reference 25 to Zhang et al., but the listed authors of reference 25 are Li, Mou, Xiong, Wang, and Xu.

  • Table 2 does not contain the claimed BIC values

    Minor

    The text attributes three near-0.5 BIC values to Table 2, but its proposed-scheme row reports a single BIC average of 112.

7 of 7

Cites

Flagged first, then by citations

Research works printed but not linked: 3

  1. Cui, L. & Cao, Y. A new S-box structure named affine-power-affine. Int. J. Innov. Comput. Inf. Control 3, 751–759 (2007).
  2. Hussain, I., Shah, T. & Mahmood, H. A new algorithm to construct secure keys for AES. Int. J. Contemp. Math. Sci. 5, 1263–1270 (2010).
  3. Xuejing, K. & Zihui, G. A new color image encryption scheme based on DNA encoding and spatiotemporal chaotic system. Signal Process.: Image Commun. 80, 115670 (2020). · DOI

Cited by

Sorted by citations

Authors
Qayyum, T., Shah, T., Khan, I., & Popa, I.-L.
Affiliations
  • Quaid-i-Azam University (PK)
  • Al-Ahliyya Amman University (JO)
  • Transylvania University of Brașov (RO)
Corresponding author
  • Qayyum, Tanveer
  • Popa, Ioan-Lucian
Venue
Scientific Reports
Published
2025-11-28
Volume
15
Issue
1
Pages
42571-42571
ISSN
2045-2322 (ISSN-L)
OpenAlex
W4416781182
Cited by
4
References
55
Citations by year
2026: 4
FWCI
1.50
Type
journal article
Language
en
Open access
Locations
  • Scientific Reports (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (submittedVersion, cc-by-nc-nd)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Topics
  • Physical Sciences › Computer Science › Computer Vision and Pattern Recognition › Chaos-based Image/Signal Encryption
  • Physical Sciences › Computer Science › Artificial Intelligence › Cryptographic Implementations and Security
  • Physical Sciences › Computer Science › Artificial Intelligence › Computer Science and Engineering
Keywords
image encryption, substitution boxes, S-box design, finite fields, Möbius transformations, nonlinearity, confusion and diffusion, cryptanalysis resistance

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Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-21.

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