obfuskey 0.1.0

Cross-language compatible integer obfuscation and bit-packing library
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176

use num_bigint::BigUint;
use num_traits::One;
use std::collections::HashMap;

use crate::error::ObfuskeyError;

#[derive(Debug, Clone)]
pub struct FieldSchema {
    pub name: String,
    pub bits: u32,
}

#[derive(Debug, Clone)]
pub struct FieldInfo {
    pub bits: u32,
    pub shift: u32,
}

#[derive(Debug)]
pub struct ObfusbitSchema {
    definition: Vec<FieldSchema>,
    field_info: HashMap<String, FieldInfo>,
    total_bits: u32,
    maximum_value: BigUint,
}

impl ObfusbitSchema {
    pub fn new(schema: Vec<FieldSchema>) -> Result<Self, ObfuskeyError> {
        if schema.is_empty() {
            return Err(ObfuskeyError::SchemaValidationError(
                "Schema must contain at least one field.".to_string(),
            ));
        }

        let mut seen_names = std::collections::HashSet::new();
        for field in &schema {
            if field.bits == 0 {
                return Err(ObfuskeyError::SchemaValidationError(format!(
                    "Field '{}' must have a positive number of bits.",
                    field.name
                )));
            }
            if !seen_names.insert(&field.name) {
                return Err(ObfuskeyError::SchemaValidationError(format!(
                    "Duplicate field name '{}'.",
                    field.name
                )));
            }
        }

        let total_bits: u32 = schema.iter().map(|f| f.bits).sum();
        let maximum_value = (BigUint::one() << total_bits) - BigUint::one();

        // Calculate field_info in reverse order (last field = LSB)
        let mut field_info = HashMap::new();
        let mut shift: u32 = 0;

        for field in schema.iter().rev() {
            field_info.insert(
                field.name.clone(),
                FieldInfo {
                    bits: field.bits,
                    shift,
                },
            );
            shift += field.bits;
        }

        Ok(ObfusbitSchema {
            definition: schema,
            field_info,
            total_bits,
            maximum_value,
        })
    }

    pub fn definition(&self) -> &[FieldSchema] {
        &self.definition
    }

    pub fn field_info(&self) -> &HashMap<String, FieldInfo> {
        &self.field_info
    }

    pub fn get_field_info(&self, name: &str) -> Option<&FieldInfo> {
        self.field_info.get(name)
    }

    pub fn total_bits(&self) -> u32 {
        self.total_bits
    }

    pub fn maximum_value(&self) -> &BigUint {
        &self.maximum_value
    }

    pub fn field_names(&self) -> impl Iterator<Item = &str> {
        self.definition.iter().map(|f| f.name.as_str())
    }

    /// Validate u64 field values against the schema.
    pub fn validate_values_u64(
        &self,
        values: &HashMap<String, u64>,
    ) -> Result<(), ObfuskeyError> {
        for field in &self.definition {
            if !values.contains_key(&field.name) {
                return Err(ObfuskeyError::ValueError(format!(
                    "Missing required field '{}'.",
                    field.name
                )));
            }
        }

        for key in values.keys() {
            if !self.field_info.contains_key(key) {
                return Err(ObfuskeyError::ValueError(format!(
                    "Unexpected field '{}'.",
                    key
                )));
            }
        }

        for (name, &value) in values {
            let info = &self.field_info[name];
            if info.bits < 64 {
                let max_field_value = (1u64 << info.bits) - 1;
                if value > max_field_value {
                    return Err(ObfuskeyError::BitOverflowError(format!(
                        "Value {} for field '{}' exceeds {} bits (max {}).",
                        value, name, info.bits, max_field_value
                    )));
                }
            }
        }

        Ok(())
    }

    /// Validate BigUint field values against the schema.
    pub fn validate_values_big(
        &self,
        values: &HashMap<String, BigUint>,
    ) -> Result<(), ObfuskeyError> {
        for field in &self.definition {
            if !values.contains_key(&field.name) {
                return Err(ObfuskeyError::ValueError(format!(
                    "Missing required field '{}'.",
                    field.name
                )));
            }
        }

        for key in values.keys() {
            if !self.field_info.contains_key(key) {
                return Err(ObfuskeyError::ValueError(format!(
                    "Unexpected field '{}'.",
                    key
                )));
            }
        }

        for (name, value) in values {
            let info = &self.field_info[name];
            let max_field_value = (BigUint::one() << info.bits) - BigUint::one();
            if *value > max_field_value {
                return Err(ObfuskeyError::BitOverflowError(format!(
                    "Value {} for field '{}' exceeds {} bits (max {}).",
                    value, name, info.bits, max_field_value
                )));
            }
        }

        Ok(())
    }
}