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comparison src/com/trilead/ssh2/signature/ECDSASHA2Verify.java @ 0:0ce5cc452d02

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initial version
author Carl Byington <carl@five-ten-sg.com>
date Thu, 22 May 2014 10:41:19 -0700
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1 /**
2 *
3 */
4 package com.trilead.ssh2.signature;
5
6 import java.io.ByteArrayOutputStream;
7 import java.io.IOException;
8 import java.io.OutputStream;
9 import java.math.BigInteger;
10 import java.security.InvalidKeyException;
11 import java.security.KeyFactory;
12 import java.security.NoSuchAlgorithmException;
13 import java.security.Signature;
14 import java.security.SignatureException;
15 import java.security.interfaces.ECPrivateKey;
16 import java.security.interfaces.ECPublicKey;
17 import java.security.spec.ECFieldFp;
18 import java.security.spec.ECParameterSpec;
19 import java.security.spec.ECPoint;
20 import java.security.spec.ECPublicKeySpec;
21 import java.security.spec.EllipticCurve;
22 import java.security.spec.InvalidKeySpecException;
23 import java.security.spec.KeySpec;
24 import java.util.Map;
25 import java.util.TreeMap;
26
27 import com.trilead.ssh2.log.Logger;
28 import com.trilead.ssh2.packets.TypesReader;
29 import com.trilead.ssh2.packets.TypesWriter;
30
31 /**
32 * @author Kenny Root
33 *
34 */
35 public class ECDSASHA2Verify {
36 private static final Logger log = Logger.getLogger(ECDSASHA2Verify.class);
37
38 public static final String ECDSA_SHA2_PREFIX = "ecdsa-sha2-";
39
40 private static final String NISTP256 = "nistp256";
41 private static final String NISTP256_OID = "1.2.840.10045.3.1.7";
42 private static final String NISTP384 = "nistp384";
43 private static final String NISTP384_OID = "1.3.132.0.34";
44 private static final String NISTP521 = "nistp521";
45 private static final String NISTP521_OID = "1.3.132.0.35";
46
47 private static final Map<String, ECParameterSpec> CURVES = new TreeMap<String, ECParameterSpec>();
48 static {
49 CURVES.put(NISTP256, EllipticCurves.nistp256);
50 CURVES.put(NISTP384, EllipticCurves.nistp384);
51 CURVES.put(NISTP521, EllipticCurves.nistp521);
52 }
53
54 private static final Map<Integer, String> CURVE_SIZES = new TreeMap<Integer, String>();
55 static {
56 CURVE_SIZES.put(256, NISTP256);
57 CURVE_SIZES.put(384, NISTP384);
58 CURVE_SIZES.put(521, NISTP521);
59 }
60
61 private static final Map<String, String> CURVE_OIDS = new TreeMap<String, String>();
62 static {
63 CURVE_OIDS.put(NISTP256_OID, NISTP256);
64 CURVE_OIDS.put(NISTP384_OID, NISTP256);
65 CURVE_OIDS.put(NISTP521_OID, NISTP256);
66 }
67
68 public static int[] getCurveSizes() {
69 int[] keys = new int[CURVE_SIZES.size()];
70 int i = 0;
71
72 for (Integer n : CURVE_SIZES.keySet().toArray(new Integer[keys.length])) {
73 keys[i++] = n;
74 }
75
76 return keys;
77 }
78
79 public static ECParameterSpec getCurveForSize(int size) {
80 final String name = CURVE_SIZES.get(size);
81
82 if (name == null) {
83 return null;
84 }
85
86 return CURVES.get(name);
87 }
88
89 public static ECPublicKey decodeSSHECDSAPublicKey(byte[] key) throws IOException {
90 TypesReader tr = new TypesReader(key);
91 String key_format = tr.readString();
92
93 if (key_format.startsWith(ECDSA_SHA2_PREFIX) == false)
94 throw new IllegalArgumentException("This is not an ECDSA public key");
95
96 String curveName = tr.readString();
97 byte[] groupBytes = tr.readByteString();
98
99 if (tr.remain() != 0)
100 throw new IOException("Padding in ECDSA public key!");
101
102 if (key_format.equals(ECDSA_SHA2_PREFIX + curveName) == false) {
103 throw new IOException("Key format is inconsistent with curve name: " + key_format
104 + " != " + curveName);
105 }
106
107 ECParameterSpec params = CURVES.get(curveName);
108
109 if (params == null) {
110 throw new IOException("Curve is not supported: " + curveName);
111 }
112
113 ECPoint group = ECDSASHA2Verify.decodeECPoint(groupBytes, params.getCurve());
114
115 if (group == null) {
116 throw new IOException("Invalid ECDSA group");
117 }
118
119 KeySpec keySpec = new ECPublicKeySpec(group, params);
120
121 try {
122 KeyFactory kf = KeyFactory.getInstance("EC");
123 return (ECPublicKey) kf.generatePublic(keySpec);
124 }
125 catch (NoSuchAlgorithmException nsae) {
126 IOException ioe = new IOException("No EC KeyFactory available");
127 ioe.initCause(nsae);
128 throw ioe;
129 }
130 catch (InvalidKeySpecException ikse) {
131 IOException ioe = new IOException("No EC KeyFactory available");
132 ioe.initCause(ikse);
133 throw ioe;
134 }
135 }
136
137 public static byte[] encodeSSHECDSAPublicKey(ECPublicKey key) throws IOException {
138 TypesWriter tw = new TypesWriter();
139 String curveName = getCurveName(key.getParams());
140 String keyFormat = ECDSA_SHA2_PREFIX + curveName;
141 tw.writeString(keyFormat);
142 tw.writeString(curveName);
143 byte[] encoded = encodeECPoint(key.getW(), key.getParams().getCurve());
144 tw.writeString(encoded, 0, encoded.length);
145 return tw.getBytes();
146 }
147
148 public static String getCurveName(ECParameterSpec params) throws IOException {
149 int fieldSize = getCurveSize(params);
150 final String curveName = getCurveName(fieldSize);
151
152 if (curveName == null) {
153 throw new IOException("invalid curve size " + fieldSize);
154 }
155
156 return curveName;
157 }
158
159 public static String getCurveName(int fieldSize) {
160 String curveName = CURVE_SIZES.get(fieldSize);
161
162 if (curveName == null) {
163 return null;
164 }
165
166 return curveName;
167 }
168
169 public static int getCurveSize(ECParameterSpec params) {
170 return params.getCurve().getField().getFieldSize();
171 }
172
173 public static ECParameterSpec getCurveForOID(String oid) {
174 String name = CURVE_OIDS.get(oid);
175
176 if (name == null)
177 return null;
178
179 return CURVES.get(name);
180 }
181
182 public static byte[] decodeSSHECDSASignature(byte[] sig) throws IOException {
183 byte[] rsArray = null;
184 TypesReader tr = new TypesReader(sig);
185 String sig_format = tr.readString();
186
187 if (sig_format.startsWith(ECDSA_SHA2_PREFIX) == false)
188 throw new IOException("Peer sent wrong signature format");
189
190 String curveName = sig_format.substring(ECDSA_SHA2_PREFIX.length());
191
192 if (CURVES.containsKey(curveName) == false) {
193 throw new IOException("Unsupported curve: " + curveName);
194 }
195
196 rsArray = tr.readByteString();
197
198 if (tr.remain() != 0)
199 throw new IOException("Padding in ECDSA signature!");
200
201 byte[] rArray;
202 byte[] sArray;
203 {
204 TypesReader rsReader = new TypesReader(rsArray);
205 rArray = rsReader.readMPINT().toByteArray();
206 sArray = rsReader.readMPINT().toByteArray();
207 }
208 int first = rArray.length;
209 int second = sArray.length;
210
211 /* We can't have the high bit set, so add an extra zero at the beginning if so. */
212 if ((rArray[0] & 0x80) != 0) {
213 first++;
214 }
215
216 if ((sArray[0] & 0x80) != 0) {
217 second++;
218 }
219
220 /* Calculate total output length */
221 ByteArrayOutputStream os = new ByteArrayOutputStream(6 + first + second);
222 /* ASN.1 SEQUENCE tag */
223 os.write(0x30);
224 /* Size of SEQUENCE */
225 writeLength(4 + first + second, os);
226 /* ASN.1 INTEGER tag */
227 os.write(0x02);
228 /* "r" INTEGER length */
229 writeLength(first, os);
230
231 /* Copy in the "r" INTEGER */
232 if (first != rArray.length) {
233 os.write(0x00);
234 }
235
236 os.write(rArray);
237 /* ASN.1 INTEGER tag */
238 os.write(0x02);
239 /* "s" INTEGER length */
240 writeLength(second, os);
241
242 /* Copy in the "s" INTEGER */
243 if (second != sArray.length) {
244 os.write(0x00);
245 }
246
247 os.write(sArray);
248 return os.toByteArray();
249 }
250
251 private static final void writeLength(int length, OutputStream os) throws IOException {
252 if (length <= 0x7F) {
253 os.write(length);
254 return;
255 }
256
257 int numOctets = 0;
258 int lenCopy = length;
259
260 while (lenCopy != 0) {
261 lenCopy >>>= 8;
262 numOctets++;
263 }
264
265 os.write(0x80 | numOctets);
266
267 for (int i = (numOctets - 1) * 8; i >= 0; i -= 8) {
268 os.write((byte)(length >> i));
269 }
270 }
271
272 public static byte[] encodeSSHECDSASignature(byte[] sig, ECParameterSpec params) throws IOException {
273 TypesWriter tw = new TypesWriter();
274 String curveName = getCurveName(params);
275 tw.writeString(ECDSA_SHA2_PREFIX + curveName);
276
277 if ((sig[0] != 0x30) || (sig[1] != sig.length - 2) || (sig[2] != 0x02)) {
278 throw new IOException("Invalid signature format");
279 }
280
281 int rLength = sig[3];
282
283 if ((rLength + 6 > sig.length) || (sig[4 + rLength] != 0x02)) {
284 throw new IOException("Invalid signature format");
285 }
286
287 int sLength = sig[5 + rLength];
288
289 if (6 + rLength + sLength > sig.length) {
290 throw new IOException("Invalid signature format");
291 }
292
293 byte[] rArray = new byte[rLength];
294 byte[] sArray = new byte[sLength];
295 System.arraycopy(sig, 4, rArray, 0, rLength);
296 System.arraycopy(sig, 6 + rLength, sArray, 0, sLength);
297 BigInteger r = new BigInteger(rArray);
298 BigInteger s = new BigInteger(sArray);
299 // Write the <r,s> to its own types writer.
300 TypesWriter rsWriter = new TypesWriter();
301 rsWriter.writeMPInt(r);
302 rsWriter.writeMPInt(s);
303 byte[] encoded = rsWriter.getBytes();
304 tw.writeString(encoded, 0, encoded.length);
305 return tw.getBytes();
306 }
307
308 public static byte[] generateSignature(byte[] message, ECPrivateKey pk) throws IOException {
309 final String algo = getSignatureAlgorithmForParams(pk.getParams());
310
311 try {
312 Signature s = Signature.getInstance(algo);
313 s.initSign(pk);
314 s.update(message);
315 return s.sign();
316 }
317 catch (NoSuchAlgorithmException e) {
318 IOException ex = new IOException();
319 ex.initCause(e);
320 throw ex;
321 }
322 catch (InvalidKeyException e) {
323 IOException ex = new IOException();
324 ex.initCause(e);
325 throw ex;
326 }
327 catch (SignatureException e) {
328 IOException ex = new IOException();
329 ex.initCause(e);
330 throw ex;
331 }
332 }
333
334 public static boolean verifySignature(byte[] message, byte[] ds, ECPublicKey dpk) throws IOException {
335 final String algo = getSignatureAlgorithmForParams(dpk.getParams());
336
337 try {
338 Signature s = Signature.getInstance(algo);
339 s.initVerify(dpk);
340 s.update(message);
341 return s.verify(ds);
342 }
343 catch (NoSuchAlgorithmException e) {
344 IOException ex = new IOException("No such algorithm");
345 ex.initCause(e);
346 throw ex;
347 }
348 catch (InvalidKeyException e) {
349 IOException ex = new IOException("No such algorithm");
350 ex.initCause(e);
351 throw ex;
352 }
353 catch (SignatureException e) {
354 IOException ex = new IOException();
355 ex.initCause(e);
356 throw ex;
357 }
358 }
359
360 private static String getSignatureAlgorithmForParams(ECParameterSpec params) {
361 int size = getCurveSize(params);
362
363 if (size <= 256) {
364 return "SHA256withECDSA";
365 }
366 else if (size <= 384) {
367 return "SHA384withECDSA";
368 }
369 else {
370 return "SHA512withECDSA";
371 }
372 }
373
374 public static String getDigestAlgorithmForParams(ECParameterSpec params) {
375 int size = getCurveSize(params);
376
377 if (size <= 256) {
378 return "SHA256";
379 }
380 else if (size <= 384) {
381 return "SHA384";
382 }
383 else {
384 return "SHA512";
385 }
386 }
387
388 /**
389 * Decode an OctetString to EllipticCurvePoint according to SECG 2.3.4
390 */
391 public static ECPoint decodeECPoint(byte[] M, EllipticCurve curve) {
392 if (M.length == 0) {
393 return null;
394 }
395
396 // M has len 2 ceil(log_2(q)/8) + 1 ?
397 int elementSize = (curve.getField().getFieldSize() + 7) / 8;
398
399 if (M.length != 2 * elementSize + 1) {
400 return null;
401 }
402
403 // step 3.2
404 if (M[0] != 0x04) {
405 return null;
406 }
407
408 // Step 3.3
409 byte[] xp = new byte[elementSize];
410 System.arraycopy(M, 1, xp, 0, elementSize);
411 // Step 3.4
412 byte[] yp = new byte[elementSize];
413 System.arraycopy(M, 1 + elementSize, yp, 0, elementSize);
414 ECPoint P = new ECPoint(new BigInteger(1, xp), new BigInteger(1, yp));
415 // TODO check point 3.5
416 // Step 3.6
417 return P;
418 }
419
420 /**
421 * Encode EllipticCurvePoint to an OctetString
422 */
423 public static byte[] encodeECPoint(ECPoint group, EllipticCurve curve) {
424 // M has len 2 ceil(log_2(q)/8) + 1 ?
425 int elementSize = (curve.getField().getFieldSize() + 7) / 8;
426 byte[] M = new byte[2 * elementSize + 1];
427 // Uncompressed format
428 M[0] = 0x04;
429 {
430 byte[] affineX = removeLeadingZeroes(group.getAffineX().toByteArray());
431 System.arraycopy(affineX, 0, M, 1 + elementSize - affineX.length, affineX.length);
432 }
433 {
434 byte[] affineY = removeLeadingZeroes(group.getAffineY().toByteArray());
435 System.arraycopy(affineY, 0, M, 1 + elementSize + elementSize - affineY.length,
436 affineY.length);
437 }
438 return M;
439 }
440
441 private static byte[] removeLeadingZeroes(byte[] input) {
442 if (input[0] != 0x00) {
443 return input;
444 }
445
446 int pos = 1;
447
448 while (pos < input.length - 1 && input[pos] == 0x00) {
449 pos++;
450 }
451
452 byte[] output = new byte[input.length - pos];
453 System.arraycopy(input, pos, output, 0, output.length);
454 return output;
455 }
456
457 public static class EllipticCurves {
458 public static ECParameterSpec nistp256 = new ECParameterSpec(
459 new EllipticCurve(
460 new ECFieldFp(new BigInteger("FFFFFFFF00000001000000000000000000000000FFFFFFFFFFFFFFFFFFFFFFFF", 16)),
461 new BigInteger("FFFFFFFF00000001000000000000000000000000FFFFFFFFFFFFFFFFFFFFFFFC", 16),
462 new BigInteger("5ac635d8aa3a93e7b3ebbd55769886bc651d06b0cc53b0f63bce3c3e27d2604b", 16)),
463 new ECPoint(new BigInteger("6B17D1F2E12C4247F8BCE6E563A440F277037D812DEB33A0F4A13945D898C296", 16),
464 new BigInteger("4FE342E2FE1A7F9B8EE7EB4A7C0F9E162BCE33576B315ECECBB6406837BF51F5", 16)),
465 new BigInteger("FFFFFFFF00000000FFFFFFFFFFFFFFFFBCE6FAADA7179E84F3B9CAC2FC632551", 16),
466 1);
467
468 public static ECParameterSpec nistp384 = new ECParameterSpec(
469 new EllipticCurve(
470 new ECFieldFp(new BigInteger("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFF0000000000000000FFFFFFFF", 16)),
471 new BigInteger("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFF0000000000000000FFFFFFFC", 16),
472 new BigInteger("B3312FA7E23EE7E4988E056BE3F82D19181D9C6EFE8141120314088F5013875AC656398D8A2ED19D2A85C8EDD3EC2AEF", 16)),
473 new ECPoint(new BigInteger("AA87CA22BE8B05378EB1C71EF320AD746E1D3B628BA79B9859F741E082542A385502F25DBF55296C3A545E3872760AB7", 16),
474 new BigInteger("3617DE4A96262C6F5D9E98BF9292DC29F8F41DBD289A147CE9DA3113B5F0B8C00A60B1CE1D7E819D7A431D7C90EA0E5F", 16)),
475 new BigInteger("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFC7634D81F4372DDF581A0DB248B0A77AECEC196ACCC52973", 16),
476 1);
477
478 public static ECParameterSpec nistp521 = new ECParameterSpec(
479 new EllipticCurve(
480 new ECFieldFp(new BigInteger("01FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 16)),
481 new BigInteger("01FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFC", 16),
482 new BigInteger("0051953EB9618E1C9A1F929A21A0B68540EEA2DA725B99B315F3B8B489918EF109E156193951EC7E937B1652C0BD3BB1BF073573DF883D2C34F1EF451FD46B503F00", 16)),
483 new ECPoint(new BigInteger("00C6858E06B70404E9CD9E3ECB662395B4429C648139053FB521F828AF606B4D3DBAA14B5E77EFE75928FE1DC127A2FFA8DE3348B3C1856A429BF97E7E31C2E5BD66", 16),
484 new BigInteger("011839296A789A3BC0045C8A5FB42C7D1BD998F54449579B446817AFBD17273E662C97EE72995EF42640C550B9013FAD0761353C7086A272C24088BE94769FD16650", 16)),
485 new BigInteger("01FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFA51868783BF2F966B7FCC0148F709A5D03BB5C9B8899C47AEBB6FB71E91386409", 16),
486 1);
487 }
488 }