visual_cryptography/
lib.rs

1//! Visual Cryptography Library
2//!
3//! This library implements various visual cryptography algorithms including:
4//! - Basic (k,n) threshold schemes
5//! - Progressive visual cryptography
6//! - Support for binary, greyscale, and color images
7//! - Configurable block sizes
8
9pub mod algorithms;
10pub mod error;
11pub mod matrix;
12pub mod qr_code;
13pub mod share;
14pub mod utils;
15
16pub use algorithms::{Algorithm, VCScheme};
17pub use error::{Result, VCError};
18pub use qr_code::{QrErrorCorrection, QrShare, QrVcConfig, QrVisualCryptography};
19pub use share::{Share, ShareType};
20
21// Re-export common types
22pub use image::{DynamicImage, ImageBuffer, Luma, Rgb, Rgba};
23
24/// Configuration for visual cryptography operations
25#[derive(Debug, Clone)]
26pub struct VCConfig {
27    /// Number of shares to generate
28    pub num_shares: usize,
29    /// Minimum shares needed to reconstruct (k in (k,n) scheme)
30    pub threshold: usize,
31    /// Block size for pixel expansion (e.g., 2 for 2x2, 3 for 3x3)
32    pub block_size: usize,
33    /// Algorithm to use
34    pub algorithm: Algorithm,
35    /// Whether to use meaningful shares (with cover images)
36    pub use_meaningful_shares: bool,
37}
38
39impl Default for VCConfig {
40    fn default() -> Self {
41        Self {
42            num_shares: 2,
43            threshold: 2,
44            block_size: 2,
45            algorithm: Algorithm::BasicThreshold,
46            use_meaningful_shares: false,
47        }
48    }
49}
50
51/// Main struct for visual cryptography operations
52pub struct VisualCryptography {
53    config: VCConfig,
54}
55
56impl VisualCryptography {
57    /// Create a new VisualCryptography instance with the given configuration
58    pub fn new(config: VCConfig) -> Result<Self> {
59        if config.threshold > config.num_shares {
60            return Err(VCError::InvalidConfiguration(
61                "Threshold cannot be greater than number of shares".to_string(),
62            ));
63        }
64        if config.threshold == 0 || config.num_shares == 0 {
65            return Err(VCError::InvalidConfiguration(
66                "Threshold and number of shares must be greater than 0".to_string(),
67            ));
68        }
69        if config.block_size == 0 {
70            return Err(VCError::InvalidConfiguration(
71                "Block size must be greater than 0".to_string(),
72            ));
73        }
74
75        Ok(Self { config })
76    }
77
78    /// Encrypt an image into shares
79    pub fn encrypt(
80        &self,
81        image: &DynamicImage,
82        cover_images: Option<Vec<DynamicImage>>,
83    ) -> Result<Vec<Share>> {
84        algorithms::encrypt(image, &self.config, cover_images)
85    }
86
87    /// Decrypt shares back into an image
88    pub fn decrypt(&self, shares: &[Share]) -> Result<DynamicImage> {
89        if shares.len() < self.config.threshold {
90            return Err(VCError::InsufficientShares {
91                required: self.config.threshold,
92                provided: shares.len(),
93            });
94        }
95        algorithms::decrypt(shares, &self.config)
96    }
97
98    /// Create a progressive visual cryptography scheme
99    pub fn progressive(num_shares: usize) -> Result<Self> {
100        Self::new(VCConfig {
101            num_shares,
102            threshold: 2, // Progressive schemes can start revealing from 2 shares
103            algorithm: Algorithm::Progressive,
104            ..Default::default()
105        })
106    }
107}
108
109#[cfg(test)]
110mod tests {
111    use super::*;
112
113    #[test]
114    fn test_config_validation() {
115        // Valid config
116        let config = VCConfig {
117            num_shares: 3,
118            threshold: 2,
119            block_size: 2,
120            algorithm: Algorithm::BasicThreshold,
121            use_meaningful_shares: false,
122        };
123        assert!(VisualCryptography::new(config).is_ok());
124
125        // Invalid: threshold > num_shares
126        let config = VCConfig {
127            num_shares: 2,
128            threshold: 3,
129            ..Default::default()
130        };
131        assert!(VisualCryptography::new(config).is_err());
132
133        // Invalid: zero threshold
134        let config = VCConfig {
135            threshold: 0,
136            ..Default::default()
137        };
138        assert!(VisualCryptography::new(config).is_err());
139    }
140
141    #[test]
142    fn test_progressive_creation() {
143        let vc = VisualCryptography::progressive(5).unwrap();
144        assert_eq!(vc.config.num_shares, 5);
145        assert_eq!(vc.config.algorithm, Algorithm::Progressive);
146    }
147}
visual_cryptography/lib.rs

visual_cryptography/
lib.rs
