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gefeili
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Move m and n from constructor to split, splitAround and resplit functions.
1 parent 666e548 commit 705fbbe

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3 files changed

+78
-68
lines changed

3 files changed

+78
-68
lines changed

‎core/src/main/java/org/bouncycastle/crypto/threshold/SecretSplitter.java‎

Lines changed: 18 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -10,14 +10,27 @@
1010
public interface SecretSplitter
1111
{
1212
/**
13-
* Creates secret shares from a given secret. The secret will be divided into shares, where the secret has a length of L bytes.
14-
*
13+
* Creates secret shares. The secret will be divided into shares, where the secret has a length of L bytes.
14+
* @param m A threshold number of shares
15+
* @param n Total number of shares
1516
* @return An array of {@code byte[][]} representing the generated secret shares for m users with l bytes each.
1617
*/
17-
SplitSecret split();
18+
SplitSecret split(int m, int n);
1819

19-
SplitSecret splitAround(SecretShare s)
20+
/**
21+
* Creates secret shares from a given secret share. The secret will be divided into shares, where the secret has a length of L bytes.
22+
* @param m A threshold number of shares
23+
* @param n Total number of shares
24+
* @return An array of {@code byte[][]} representing the generated secret shares for m users with l bytes each.
25+
*/
26+
SplitSecret splitAround(SecretShare s, int m, int n)
2027
throws IOException;
2128

22-
SplitSecret resplit(byte[] secret);
29+
/**
30+
* Creates secret shares from a given secret. The secret will be divided into shares, where the secret has a length of L bytes.
31+
* @param m A threshold number of shares
32+
* @param n Total number of shares
33+
* @return An array of {@code byte[][]} representing the generated secret shares for m users with l bytes each.
34+
*/
35+
SplitSecret resplit(byte[] secret, int m, int n);
2336
}

‎core/src/main/java/org/bouncycastle/crypto/threshold/ShamirSecretSplitter.java‎

Lines changed: 33 additions & 35 deletions
Original file line numberDiff line numberDiff line change
@@ -5,6 +5,7 @@
55

66
import org.bouncycastle.util.Arrays;
77

8+
89
public class ShamirSecretSplitter
910
implements SecretSplitter
1011
{
@@ -25,49 +26,25 @@ public enum Mode
2526
* Length of the secret
2627
*/
2728
protected int l;
28-
/**
29-
* A threshold number of shares
30-
*/
31-
protected int m;
32-
/**
33-
* Total number of shares
34-
* m <= n <= 255
35-
*/
36-
protected int n;
37-
protected byte[][] p;
29+
3830
protected SecureRandom random;
3931

40-
public ShamirSecretSplitter(Algorithm algorithm, Mode mode, int l, int m, int n, SecureRandom random)
32+
public ShamirSecretSplitter(Algorithm algorithm, Mode mode, int l, SecureRandom random)
4133
{
4234
if (l < 0 || l > 65534)
4335
{
4436
throw new IllegalArgumentException("Invalid input: l ranges from 0 to 65534 (2^16-2) bytes.");
4537
}
46-
if (m < 1 || m > 255)
47-
{
48-
throw new IllegalArgumentException("Invalid input: m must be less than 256 and positive.");
49-
}
50-
if (n < m || n > 255)
51-
{
52-
throw new IllegalArgumentException("Invalid input: n must be less than 256 and greater than or equal to n.");
53-
}
38+
5439
poly = Polynomial.newInstance(algorithm, mode);
5540
this.l = l;
56-
this.m = m;
57-
this.n = n;
5841
this.random = random;
59-
p = new byte[n][m];
60-
for (int i = 0; i < n; i++)
61-
{
62-
for (int j = 0; j < m; j++)
63-
{
64-
p[i][j] = poly.gfPow((byte)(i + 1), (byte)j);
65-
}
66-
}
6742
}
6843

69-
public ShamirSplitSecret split()
44+
45+
public ShamirSplitSecret split(int m, int n)
7046
{
47+
byte[][] p = initP(m, n);
7148
byte[][] sr = new byte[m][l];
7249
ShamirSplitSecretShare[] secretShares = new ShamirSplitSecretShare[l];
7350
int i;
@@ -83,9 +60,10 @@ public ShamirSplitSecret split()
8360
}
8461

8562
@Override
86-
public ShamirSplitSecret splitAround(SecretShare s)
63+
public ShamirSplitSecret splitAround(SecretShare s, int m, int n)
8764
throws IOException
8865
{
66+
byte[][] p = initP(m, n);
8967
byte[][] sr = new byte[m][l];
9068
ShamirSplitSecretShare[] secretShares = new ShamirSplitSecretShare[l];
9169
byte[] ss0 = s.getEncoded();
@@ -114,11 +92,12 @@ public ShamirSplitSecret splitAround(SecretShare s)
11492
}
11593

11694
@Override
117-
public ShamirSplitSecret resplit(byte[] secret)
95+
public ShamirSplitSecret resplit(byte[] secret, int m, int n)
11896
{
97+
byte[][] p = initP(m, n);
11998
byte[][] sr = new byte[m][l];
12099
ShamirSplitSecretShare[] secretShares = new ShamirSplitSecretShare[l];
121-
sr[0] = secret;
100+
sr[0] = Arrays.clone(secret);
122101
int i;
123102
for (i = 1; i < m; i++)
124103
{
@@ -131,5 +110,24 @@ public ShamirSplitSecret resplit(byte[] secret)
131110
return new ShamirSplitSecret(poly, secretShares);
132111
}
133112

134-
135-
}
113+
private byte[][] initP(int m, int n)
114+
{
115+
if (m < 1 || m > 255)
116+
{
117+
throw new IllegalArgumentException("Invalid input: m must be less than 256 and positive.");
118+
}
119+
if (n < m || n > 255)
120+
{
121+
throw new IllegalArgumentException("Invalid input: n must be less than 256 and greater than or equal to n.");
122+
}
123+
byte[][] p = new byte[n][m];
124+
for (int i = 0; i < n; i++)
125+
{
126+
for (int j = 0; j < m; j++)
127+
{
128+
p[i][j] = poly.gfPow((byte)(i + 1), (byte)j);
129+
}
130+
}
131+
return p;
132+
}
133+
}

‎core/src/test/java/org/bouncycastle/crypto/threshold/test/ShamirSecretSplitterTest.java‎

Lines changed: 27 additions & 28 deletions
Original file line numberDiff line numberDiff line change
@@ -42,17 +42,17 @@ public void testShamirSecretResplit()
4242
SecureRandom random = new SecureRandom();
4343
ShamirSecretSplitter.Algorithm algorithm = ShamirSecretSplitter.Algorithm.AES;
4444
ShamirSecretSplitter.Mode mode = ShamirSecretSplitter.Mode.Table;
45-
ShamirSecretSplitter splitter = new ShamirSecretSplitter(algorithm, mode, l, m, n, random);//, secretshare);
45+
ShamirSecretSplitter splitter = new ShamirSecretSplitter(algorithm, mode, l, random);
4646

47-
ShamirSplitSecret splitSecret = splitter.split();
47+
ShamirSplitSecret splitSecret = splitter.split(m, n);
4848
ShamirSplitSecretShare[] secretShares = splitSecret.getSecretShares();
4949

5050
ShamirSplitSecretShare[] secretShares1 = new ShamirSplitSecretShare[]{secretShares[0], secretShares[1], secretShares[2]};
5151
ShamirSplitSecret splitSecret1 = new ShamirSplitSecret(algorithm, mode, secretShares1);
5252
byte[] secret1 = splitSecret1.getSecret();
5353

5454

55-
ShamirSplitSecret splitSecret2 = splitter.resplit(secret1);
55+
ShamirSplitSecret splitSecret2 = splitter.resplit(secret1, m, n);
5656
ShamirSplitSecretShare[] secretShares2 = splitSecret2.getSecretShares();
5757
ShamirSplitSecretShare[] secretShares3 = new ShamirSplitSecretShare[]{secretShares2[0], secretShares2[1], secretShares2[2]};
5858
ShamirSplitSecret splitSecret3 = new ShamirSplitSecret(algorithm, mode, secretShares3);
@@ -62,7 +62,6 @@ public void testShamirSecretResplit()
6262
Assert.assertArrayEquals(secret1, secret3);
6363
Assert.assertFalse(Arrays.areEqual(Arrays.concatenate(secretShares[0].getEncoded(), secretShares[1].getEncoded(), secretShares[2].getEncoded()),
6464
Arrays.concatenate(secretShares2[0].getEncoded(), secretShares2[1].getEncoded(), secretShares2[2].getEncoded())));
65-
6665
}
6766

6867
public void testShamirSecretMultipleDivide()
@@ -72,9 +71,9 @@ public void testShamirSecretMultipleDivide()
7271
SecureRandom random = new SecureRandom();
7372
ShamirSecretSplitter.Algorithm algorithm = ShamirSecretSplitter.Algorithm.AES;
7473
ShamirSecretSplitter.Mode mode = ShamirSecretSplitter.Mode.Table;
75-
ShamirSecretSplitter splitter = new ShamirSecretSplitter(algorithm, mode, l, m, n, random);//, secretshare);
74+
ShamirSecretSplitter splitter = new ShamirSecretSplitter(algorithm, mode, l, random);
7675

77-
ShamirSplitSecret splitSecret = splitter.split();
76+
ShamirSplitSecret splitSecret = splitter.split(m, n);
7877
ShamirSplitSecretShare[] secretShares = splitSecret.getSecretShares();
7978

8079
ShamirSplitSecretShare[] secretShares1 = new ShamirSplitSecretShare[]{secretShares[0], secretShares[1], secretShares[2]};
@@ -110,14 +109,14 @@ public void testShamirSecretSplitterSplitAround()
110109
int l = 9, m = 3, n = 9;
111110
ShamirSecretSplitter.Algorithm algorithm = ShamirSecretSplitter.Algorithm.AES;
112111
ShamirSecretSplitter.Mode mode = ShamirSecretSplitter.Mode.Table;
113-
ShamirSecretSplitter splitter = new ShamirSecretSplitter(algorithm, mode, l, m, n, new SecureRandom());//, secretshare);
112+
ShamirSecretSplitter splitter = new ShamirSecretSplitter(algorithm, mode, l, new SecureRandom());
114113
byte[] seed = Hex.decode("010203040506070809");
115114
//SecureRandom random = new SecureRandom();
116115

117116
//random.nextBytes(seed);
118117
//System.out.println(Hex.decode(seed));
119118
ShamirSplitSecretShare ss = new ShamirSplitSecretShare(seed);
120-
ShamirSplitSecret splitSecret = splitter.splitAround(ss);
119+
ShamirSplitSecret splitSecret = splitter.splitAround(ss, m, n);
121120
ShamirSplitSecretShare[] secretShares = splitSecret.getSecretShares();
122121
Assert.assertArrayEquals(secretShares[0].getEncoded(), seed);
123122

@@ -154,8 +153,8 @@ public void testShamirSecretSplitter()
154153
int l = 9, m = 3, n = 9;
155154
ShamirSecretSplitter.Algorithm algorithm = ShamirSecretSplitter.Algorithm.AES;
156155
ShamirSecretSplitter.Mode mode = ShamirSecretSplitter.Mode.Table;
157-
ShamirSecretSplitter splitter = new ShamirSecretSplitter(algorithm, mode, l, m, n, new SecureRandom());//, secretshare);
158-
ShamirSplitSecret splitSecret = splitter.split(); //integers multiply/ divide
156+
ShamirSecretSplitter splitter = new ShamirSecretSplitter(algorithm, mode, l, new SecureRandom());//, secretshare);
157+
ShamirSplitSecret splitSecret = splitter.split(m, n); //integers multiply/ divide
159158
ShamirSplitSecretShare[] secretShares = splitSecret.getSecretShares();
160159

161160
ShamirSplitSecretShare[] secretShares1 = new ShamirSplitSecretShare[]{secretShares[0], secretShares[1], secretShares[2]};
@@ -955,7 +954,7 @@ public void testPolynomial()
955954
@Override
956955
public ShamirSecretSplitter newInstance(int l, int m, int n, SecureRandom random)
957956
{
958-
return new ShamirSecretSplitter(ShamirSecretSplitter.Algorithm.AES, ShamirSecretSplitter.Mode.Native, l, m, n, random);
957+
return new ShamirSecretSplitter(ShamirSecretSplitter.Algorithm.AES, ShamirSecretSplitter.Mode.Native, l, random);
959958
}
960959

961960
@Override
@@ -970,7 +969,7 @@ public ShamirSplitSecret newInstance(ShamirSplitSecretShare[] secretShares)
970969
@Override
971970
public ShamirSecretSplitter newInstance(int l, int m, int n, SecureRandom random)
972971
{
973-
return new ShamirSecretSplitter(ShamirSecretSplitter.Algorithm.AES, ShamirSecretSplitter.Mode.Table, l, m, n, random);
972+
return new ShamirSecretSplitter(ShamirSecretSplitter.Algorithm.AES, ShamirSecretSplitter.Mode.Table, l, random);
974973
}
975974

976975
@Override
@@ -985,7 +984,7 @@ public ShamirSplitSecret newInstance(ShamirSplitSecretShare[] secretShares)
985984
@Override
986985
public ShamirSecretSplitter newInstance(int l, int m, int n, SecureRandom random)
987986
{
988-
return new ShamirSecretSplitter(ShamirSecretSplitter.Algorithm.RSA, ShamirSecretSplitter.Mode.Native, l, m, n, random);
987+
return new ShamirSecretSplitter(ShamirSecretSplitter.Algorithm.RSA, ShamirSecretSplitter.Mode.Native, l, random);
989988
}
990989

991990
@Override
@@ -1000,7 +999,7 @@ public ShamirSplitSecret newInstance(ShamirSplitSecretShare[] secretShares)
1000999
@Override
10011000
public ShamirSecretSplitter newInstance(int l, int m, int n, SecureRandom random)
10021001
{
1003-
return new ShamirSecretSplitter(ShamirSecretSplitter.Algorithm.RSA, ShamirSecretSplitter.Mode.Table, l, m, n, random);
1002+
return new ShamirSecretSplitter(ShamirSecretSplitter.Algorithm.RSA, ShamirSecretSplitter.Mode.Table, l,random);
10041003
}
10051004

10061005
@Override
@@ -1015,27 +1014,27 @@ private void testPolynoimial1(PolynomialFactory polynomialFactory)
10151014
throws IOException
10161015
{
10171016
ShamirSecretSplitter splitter = polynomialFactory.newInstance(5, 2, 2, getSecureRandom(TV011B_TV1_SR));
1018-
testMatrixMultiplication(splitter, TV011B_TV1_SPLITS);
1017+
testMatrixMultiplication(splitter, TV011B_TV1_SPLITS, 2, 2);
10191018
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2}, TV011B_TV1_1_2_SPLITS)), TV011B_TV1_SECRET);
10201019
splitter = polynomialFactory.newInstance(5, 2, 4, getSecureRandom(TV011B_TV2_SR));
1021-
testMatrixMultiplication(splitter, TV011B_TV2_SPLITS);
1020+
testMatrixMultiplication(splitter, TV011B_TV2_SPLITS, 2, 4);
10221021
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2}, TV011B_TV2_1_2_SPLITS)), TV011B_TV2_SECRET);
10231022
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 4}, TV011B_TV2_1_4_SPLITS)), TV011B_TV2_SECRET);
10241023
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{3, 4}, TV011B_TV2_3_4_SPLITS)), TV011B_TV2_SECRET);
10251024
splitter = polynomialFactory.newInstance(5, 3, 4, getSecureRandom(TV011B_TV3_SR));
1026-
testMatrixMultiplication(splitter, TV011B_TV3_SPLITS);
1025+
testMatrixMultiplication(splitter, TV011B_TV3_SPLITS, 3, 4);
10271026
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2, 3}, TV011B_TV3_1_2_3_SPLITS)), TV011B_TV3_SECRET);
10281027
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2, 4}, TV011B_TV3_1_2_4_SPLITS)), TV011B_TV3_SECRET);
10291028
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 3, 4}, TV011B_TV3_1_3_4_SPLITS)), TV011B_TV3_SECRET);
10301029
splitter = polynomialFactory.newInstance(5, 4, 4, getSecureRandom(TV011B_TV4_SR));
1031-
testMatrixMultiplication(splitter, TV011B_TV4_SPLITS);
1030+
testMatrixMultiplication(splitter, TV011B_TV4_SPLITS, 4, 4);
10321031
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2, 3, 4}, TV011B_TV4_1_2_3_4_SPLITS)), TV011B_TV4_SECRET);
10331032
splitter = polynomialFactory.newInstance(9, 2, 9, getSecureRandom(TV011B_TV5_SR));
1034-
testMatrixMultiplication(splitter, TV011B_TV5_SPLITS);
1033+
testMatrixMultiplication(splitter, TV011B_TV5_SPLITS, 2, 9);
10351034
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2}, TV011B_TV5_1_2_SPLITS)), TV011B_TV5_SECRET);
10361035
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{8, 9}, TV011B_TV5_8_9_SPLITS)), TV011B_TV5_SECRET);
10371036
splitter = polynomialFactory.newInstance(15, 3, 5, getSecureRandom(TV011B_TV6_SR));
1038-
testMatrixMultiplication(splitter, TV011B_TV6_SPLITS);
1037+
testMatrixMultiplication(splitter, TV011B_TV6_SPLITS, 3, 5);
10391038
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2, 3}, TV011B_TV6_1_2_3_SPLITS)), TV011B_TV6_SECRET);
10401039
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{2, 3, 4}, TV011B_TV6_2_3_4_SPLITS)), TV011B_TV6_SECRET);
10411040
}
@@ -1044,27 +1043,27 @@ private void testPolynoimial2(PolynomialFactory polynomialFactory)
10441043
throws IOException
10451044
{
10461045
ShamirSecretSplitter poly = polynomialFactory.newInstance(5, 2, 2, getSecureRandom(TV011D_TV1_SR));
1047-
testMatrixMultiplication(poly, TV011D_TV1_SPLITS);
1046+
testMatrixMultiplication(poly, TV011D_TV1_SPLITS, 2, 2);
10481047
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2}, TV011D_TV1_1_2_SPLITS)), TV011D_TV1_SECRET);
10491048
poly = polynomialFactory.newInstance(5, 2, 4, getSecureRandom(TV011D_TV2_SR));
1050-
testMatrixMultiplication(poly, TV011D_TV2_SPLITS);
1049+
testMatrixMultiplication(poly, TV011D_TV2_SPLITS, 2, 4);
10511050
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2}, TV011D_TV2_1_2_SPLITS)), TV011D_TV2_SECRET);
10521051
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 4}, TV011D_TV2_1_4_SPLITS)), TV011D_TV2_SECRET);
10531052
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{3, 4}, TV011D_TV2_3_4_SPLITS)), TV011D_TV2_SECRET);
10541053
poly = polynomialFactory.newInstance(5, 3, 4, getSecureRandom(TV011D_TV3_SR));
1055-
testMatrixMultiplication(poly, TV011D_TV3_SPLITS);
1054+
testMatrixMultiplication(poly, TV011D_TV3_SPLITS, 3, 4);
10561055
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2, 3}, TV011D_TV3_1_2_3_SPLITS)), TV011D_TV3_SECRET);
10571056
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2, 4}, TV011D_TV3_1_2_4_SPLITS)), TV011D_TV3_SECRET);
10581057
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 3, 4}, TV011D_TV3_1_3_4_SPLITS)), TV011D_TV3_SECRET);
10591058
poly = polynomialFactory.newInstance(5, 4, 4, getSecureRandom(TV011D_TV4_SR));
1060-
testMatrixMultiplication(poly, TV011D_TV4_SPLITS);
1059+
testMatrixMultiplication(poly, TV011D_TV4_SPLITS, 4, 4);
10611060
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2, 3, 4}, TV011D_TV4_1_2_3_4_SPLITS)), TV011D_TV4_SECRET);
10621061
poly = polynomialFactory.newInstance(9, 2, 9, getSecureRandom(TV011D_TV5_SR));
1063-
testMatrixMultiplication(poly, TV011D_TV5_SPLITS);
1062+
testMatrixMultiplication(poly, TV011D_TV5_SPLITS, 2, 9);
10641063
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2}, TV011D_TV5_1_2_SPLITS)), TV011D_TV5_SECRET);
10651064
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{8, 9}, TV011D_TV5_8_9_SPLITS)), TV011D_TV5_SECRET);
10661065
poly = polynomialFactory.newInstance(15, 3, 5, getSecureRandom(TV011D_TV6_SR));
1067-
testMatrixMultiplication(poly, TV011D_TV6_SPLITS);
1066+
testMatrixMultiplication(poly, TV011D_TV6_SPLITS, 3, 5);
10681067
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{1, 2, 3}, TV011D_TV6_1_2_3_SPLITS)), TV011D_TV6_SECRET);
10691068
testRecombine(polynomialFactory.newInstance(getShamirSplitSecretShareArray(new int[]{2, 3, 4}, TV011D_TV6_2_3_4_SPLITS)), TV011D_TV6_SECRET);
10701069
}
@@ -1092,10 +1091,10 @@ static ShamirSplitSecretShare[] getShamirSplitSecretShareArray(int[] rr, byte[][
10921091
return secretShares;
10931092
}
10941093

1095-
static void testMatrixMultiplication(ShamirSecretSplitter poly, byte[][] splits)
1094+
static void testMatrixMultiplication(ShamirSecretSplitter poly, byte[][] splits, int m, int n)
10961095
throws IOException
10971096
{
1098-
ShamirSplitSecretShare[] secretShares = poly.split().getSecretShares();
1097+
ShamirSplitSecretShare[] secretShares = poly.split(m, n).getSecretShares();
10991098
byte[][] result = new byte[splits.length][splits[0].length];
11001099
for (int i = 0; i < result.length; ++i)
11011100
{

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