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ShreeHarishShreeHarish
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updated documentation
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‎hashing/ripemd_160.cpp‎

Lines changed: 106 additions & 72 deletions
Original file line numberDiff line numberDiff line change
@@ -25,7 +25,7 @@
2525

2626
#include <cassert> /// For assert
2727
#include <cstdint> /// For data types such as std::int32_t, std::uint32_t, etc
28-
#include <iomanip> /// For functions like setw, setfill
28+
#include <iomanip> /// For functions like std::setw, std::setfill
2929
#include <iostream> /// For managing io
3030
#include <sstream> /// For bytes to hex string
3131
#include <string> /// For string data
@@ -45,70 +45,10 @@ namespace hashing {
4545
class RIPEMD160 {
4646
private:
4747
/**
48-
* @brief converts string data to vector of uint32_t (4 byte words)
49-
* @details converts the string to 4 byte words in little endian format
50-
* after adding padding and message length as specified in the algorithm
51-
* @param data data to be converted
52-
* @return vector of 4 byte words in little endian format
53-
*/
54-
std::vector<uint32_t> string_to_word_data(std::string &data) {
55-
std::vector<uint32_t> word_data;
56-
57-
// convert string data to 4 byte words in little endian format
58-
for (uint64_t i = 0; i < (data.size() / 4) * 4; i += 4) {
59-
word_data.push_back(static_cast<uint32_t>(data[i]) |
60-
(static_cast<uint32_t>(data[i + 1]) << 8) |
61-
(static_cast<uint32_t>(data[i + 2]) << 16) |
62-
(static_cast<uint32_t>(data[i + 3]) << 24));
63-
}
64-
65-
// add padding to data
66-
int extra = data.size() % 4;
67-
68-
switch (extra) {
69-
case 0:
70-
word_data.push_back(0x00000080);
71-
break;
72-
73-
case 1:
74-
word_data.push_back(
75-
static_cast<uint32_t>(data[data.size() - 1]) | 0x00008000);
76-
break;
77-
78-
case 2:
79-
word_data.push_back(
80-
static_cast<uint32_t>(data[data.size() - 2]) |
81-
(static_cast<uint32_t>(data[data.size() - 1]) << 8) |
82-
0x00800000);
83-
break;
84-
85-
case 3:
86-
word_data.push_back(
87-
static_cast<uint32_t>(data[data.size() - 3]) |
88-
(static_cast<uint32_t>(data[data.size() - 2]) << 8) |
89-
(static_cast<uint32_t>(data[data.size() - 1]) << 16) |
90-
0x80000000);
91-
break;
92-
}
93-
94-
while (word_data.size() % 16 != 14) {
95-
word_data.push_back(0x00000000);
96-
}
97-
98-
// add message length
99-
word_data.push_back((static_cast<uint64_t>(data.size()) << 3) &
100-
0xffffffff);
101-
word_data.push_back((static_cast<uint64_t>(data.size()) >> 29) &
102-
0xffffffff);
103-
104-
return word_data;
105-
}
106-
107-
/**
108-
* @brief implements f(j,x,y,z)
109-
* @param j round number j / 16
110-
* @param B,C,D the state values
111-
* @return returns the function value
48+
* @brief Implements f(j,x,y,z)
49+
* @param j Round number j / 16
50+
* @param B,C,D The state values
51+
* @return Returns the function value
11252
*/
11353
uint32_t f(int j, uint32_t B, uint32_t C, uint32_t D) {
11454
switch (j) {
@@ -126,9 +66,9 @@ class RIPEMD160 {
12666
}
12767

12868
/**
129-
* @brief implements K value for a given j
130-
* @param j round number j / 16
131-
* @return appropriate K value
69+
* @brief Implements K value for a given j
70+
* @param j Round number j / 16
71+
* @return Appropriate K value
13272
*/
13373
uint32_t K(int j) {
13474
switch (j) {
@@ -146,9 +86,9 @@ class RIPEMD160 {
14686
}
14787

14888
/**
149-
* @brief implements K' value for a given j
150-
* @param j round number j / 16
151-
* @return appropriate K' value
89+
* @brief Implements K' value for a given j
90+
* @param j Round number j / 16
91+
* @return Appropriate K' value
15292
*/
15393
uint32_t K_dash(int j) {
15494
switch (j) {
@@ -165,34 +105,128 @@ class RIPEMD160 {
165105
}
166106
}
167107

108+
/**
109+
* @brief Specifies r value for a given j.
110+
*
111+
* @details Specifies the order in which 4-byte words of the current
112+
* 512-bits block are accessed and processed in each step of the compression
113+
* function. Introduces non-linearity to the code. It is used by one of the
114+
* parallel path.
115+
*/
168116
static constexpr int r[80] = {
169117
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
170118
7, 4, 13, 1, 10, 6, 15, 3, 12, 0, 9, 5, 2, 14, 11, 8,
171119
3, 10, 14, 4, 9, 15, 8, 1, 2, 7, 0, 6, 13, 11, 5, 12,
172120
1, 9, 11, 10, 0, 8, 12, 4, 13, 3, 7, 15, 14, 5, 6, 2,
173121
4, 0, 5, 9, 7, 12, 2, 10, 14, 1, 3, 8, 11, 6, 15, 13};
174122

123+
/**
124+
* @brief Specifies the r' value a given j.
125+
*
126+
* @details Specifies the order in which 4-byte words of the current
127+
* 512-bits block are accessed and processed in each step of the compression
128+
* function. Introduces non-linearity to the code. It is used in the other
129+
* parallel path.
130+
*/
175131
static constexpr int r_dash[80] = {
176132
5, 14, 7, 0, 9, 2, 11, 4, 13, 6, 15, 8, 1, 10, 3, 12,
177133
6, 11, 3, 7, 0, 13, 5, 10, 14, 15, 8, 12, 4, 9, 1, 2,
178134
15, 5, 1, 3, 7, 14, 6, 9, 11, 8, 12, 2, 10, 0, 4, 13,
179135
8, 6, 4, 1, 3, 11, 15, 0, 5, 12, 2, 13, 9, 7, 10, 14,
180136
12, 15, 10, 4, 1, 5, 8, 7, 6, 2, 13, 14, 0, 3, 9, 11};
181137

138+
/**
139+
* @brief Specifies the s value for a given j.
140+
*
141+
* @details Determines the number of bits to cyclically shift (left rotate)
142+
* the result of each step. The different shift values prevent patterns from
143+
* emerging in the output, which is crucial for achieving properties like
144+
* the avalanche effect (where a small change in the input results in a
145+
* large change in the output). It is used by one of the parallel path.
146+
*/
182147
static constexpr int s[80] = {
183148
11, 14, 15, 12, 5, 8, 7, 9, 11, 13, 14, 15, 6, 7, 9, 8,
184149
7, 6, 8, 13, 11, 9, 7, 15, 7, 12, 15, 9, 11, 7, 13, 12,
185150
11, 13, 6, 7, 14, 9, 13, 15, 14, 8, 13, 6, 5, 12, 7, 5,
186151
11, 12, 14, 15, 14, 15, 9, 8, 9, 14, 5, 6, 8, 6, 5, 12,
187152
9, 15, 5, 11, 6, 8, 13, 12, 5, 12, 13, 14, 11, 8, 5, 6};
188153

154+
/**
155+
* @brief Specifies the s' value for a given j.
156+
*
157+
* @details Determines the number of bits to cyclically shift (left rotate)
158+
* the result of each step. The different shift values prevent patterns from
159+
* emerging in the output, which is crucial for achieving properties like
160+
* the avalanche effect (where a small change in the input results in a
161+
* large change in the output). It is used in the other parallel path.
162+
*/
189163
static constexpr int s_dash[80] = {
190164
8, 9, 9, 11, 13, 15, 15, 5, 7, 7, 8, 11, 14, 14, 12, 6,
191165
9, 13, 15, 7, 12, 8, 9, 11, 7, 7, 12, 7, 6, 15, 13, 11,
192166
9, 7, 15, 11, 8, 6, 6, 14, 12, 13, 5, 14, 13, 13, 7, 5,
193167
15, 5, 8, 11, 14, 14, 6, 14, 6, 9, 12, 9, 12, 5, 15, 8,
194168
8, 5, 12, 9, 12, 5, 14, 6, 8, 13, 6, 5, 15, 13, 11, 11};
195169

170+
/**
171+
* @brief converts string data to vector of uint32_t (4 byte words)
172+
* @details converts the string to 4 byte words in little endian format
173+
* after adding padding and message length as specified in the algorithm
174+
* @param data data to be converted
175+
* @return vector of 4 byte words in little endian format
176+
*/
177+
std::vector<uint32_t> string_to_word_data(std::string &data) {
178+
std::vector<uint32_t> word_data;
179+
180+
// convert string data to 4 byte words in little endian format
181+
for (uint64_t i = 0; i < (data.size() / 4) * 4; i += 4) {
182+
word_data.push_back(static_cast<uint32_t>(data[i]) |
183+
(static_cast<uint32_t>(data[i + 1]) << 8) |
184+
(static_cast<uint32_t>(data[i + 2]) << 16) |
185+
(static_cast<uint32_t>(data[i + 3]) << 24));
186+
}
187+
188+
// add padding to data
189+
int extra = data.size() % 4;
190+
191+
switch (extra) {
192+
case 0:
193+
word_data.push_back(0x00000080);
194+
break;
195+
196+
case 1:
197+
word_data.push_back(
198+
static_cast<uint32_t>(data[data.size() - 1]) | 0x00008000);
199+
break;
200+
201+
case 2:
202+
word_data.push_back(
203+
static_cast<uint32_t>(data[data.size() - 2]) |
204+
(static_cast<uint32_t>(data[data.size() - 1]) << 8) |
205+
0x00800000);
206+
break;
207+
208+
case 3:
209+
word_data.push_back(
210+
static_cast<uint32_t>(data[data.size() - 3]) |
211+
(static_cast<uint32_t>(data[data.size() - 2]) << 8) |
212+
(static_cast<uint32_t>(data[data.size() - 1]) << 16) |
213+
0x80000000);
214+
break;
215+
}
216+
217+
while (word_data.size() % 16 != 14) {
218+
word_data.push_back(0x00000000);
219+
}
220+
221+
// add message length
222+
word_data.push_back((static_cast<uint64_t>(data.size()) << 3) &
223+
0xffffffff);
224+
word_data.push_back((static_cast<uint64_t>(data.size()) >> 29) &
225+
0xffffffff);
226+
227+
return word_data;
228+
}
229+
196230
/**
197231
* @brief cyclic left shift of uint32_t
198232
* @param value value to be shifted
@@ -395,6 +429,6 @@ static void test() {
395429
* @return 0 on exit
396430
*/
397431
int main() {
398-
test(); // run self test implementation
432+
test(); // run self test implementation
399433
return 0;
400434
}

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