0
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1 /*
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2 * ConnectBot: simple, powerful, open-source SSH client for Android
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3 * Copyright 2007 Kenny Root, Jeffrey Sharkey
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4 *
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5 * Licensed under the Apache License, Version 2.0 (the "License");
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6 * you may not use this file except in compliance with the License.
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7 * You may obtain a copy of the License at
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8 *
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9 * http://www.apache.org/licenses/LICENSE-2.0
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10 *
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11 * Unless required by applicable law or agreed to in writing, software
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12 * distributed under the License is distributed on an "AS IS" BASIS,
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13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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14 * See the License for the specific language governing permissions and
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15 * limitations under the License.
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16 */
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17
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18 package com.five_ten_sg.connectbot.util;
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19
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20 import java.io.IOException;
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21 import java.math.BigInteger;
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22 import java.security.AlgorithmParameters;
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23 import java.security.InvalidAlgorithmParameterException;
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24 import java.security.InvalidKeyException;
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25 import java.security.Key;
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26 import java.security.KeyFactory;
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27 import java.security.KeyPair;
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28 import java.security.MessageDigest;
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29 import java.security.NoSuchAlgorithmException;
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30 import java.security.PrivateKey;
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31 import java.security.PublicKey;
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32 import java.security.SecureRandom;
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33 import java.security.interfaces.DSAParams;
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34 import java.security.interfaces.DSAPrivateKey;
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35 import java.security.interfaces.DSAPublicKey;
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36 import java.security.interfaces.ECPrivateKey;
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37 import java.security.interfaces.ECPublicKey;
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38 import java.security.interfaces.RSAPrivateCrtKey;
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39 import java.security.interfaces.RSAPublicKey;
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40 import java.security.spec.DSAPublicKeySpec;
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41 import java.security.spec.ECParameterSpec;
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42 import java.security.spec.ECPoint;
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43 import java.security.spec.ECPublicKeySpec;
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44 import java.security.spec.InvalidKeySpecException;
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45 import java.security.spec.InvalidParameterSpecException;
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46 import java.security.spec.KeySpec;
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47 import java.security.spec.PKCS8EncodedKeySpec;
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48 import java.security.spec.RSAPublicKeySpec;
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49 import java.security.spec.X509EncodedKeySpec;
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50 import java.util.Arrays;
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51
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52 import javax.crypto.BadPaddingException;
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53 import javax.crypto.Cipher;
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54 import javax.crypto.EncryptedPrivateKeyInfo;
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55 import javax.crypto.IllegalBlockSizeException;
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56 import javax.crypto.NoSuchPaddingException;
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57 import javax.crypto.SecretKeyFactory;
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58 import javax.crypto.spec.PBEKeySpec;
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59 import javax.crypto.spec.PBEParameterSpec;
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60 import javax.crypto.spec.SecretKeySpec;
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61
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62 import org.keyczar.jce.EcCore;
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63
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64 import com.five_ten_sg.connectbot.bean.PubkeyBean;
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65 import android.util.Log;
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66
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67 import com.trilead.ssh2.crypto.Base64;
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68 import com.trilead.ssh2.crypto.SimpleDERReader;
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69 import com.trilead.ssh2.signature.DSASHA1Verify;
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70 import com.trilead.ssh2.signature.ECDSASHA2Verify;
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71 import com.trilead.ssh2.signature.RSASHA1Verify;
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72
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73 public class PubkeyUtils {
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74 private static final String TAG = "PubkeyUtils";
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75
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76 public static final String PKCS8_START = "-----BEGIN PRIVATE KEY-----";
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77 public static final String PKCS8_END = "-----END PRIVATE KEY-----";
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78
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79 // Size in bytes of salt to use.
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80 private static final int SALT_SIZE = 8;
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81
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82 // Number of iterations for password hashing. PKCS#5 recommends 1000
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83 private static final int ITERATIONS = 1000;
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84
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85 // Cannot be instantiated
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86 private PubkeyUtils() {
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87 }
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88
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89 public static String formatKey(Key key) {
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90 String algo = key.getAlgorithm();
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91 String fmt = key.getFormat();
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92 byte[] encoded = key.getEncoded();
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93 return "Key[algorithm=" + algo + ", format=" + fmt +
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94 ", bytes=" + encoded.length + "]";
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95 }
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96
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97 public static byte[] sha256(byte[] data) throws NoSuchAlgorithmException {
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98 return MessageDigest.getInstance("SHA-256").digest(data);
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99 }
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100
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101 public static byte[] cipher(int mode, byte[] data, byte[] secret) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
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102 SecretKeySpec secretKeySpec = new SecretKeySpec(sha256(secret), "AES");
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103 Cipher c = Cipher.getInstance("AES");
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104 c.init(mode, secretKeySpec);
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105 return c.doFinal(data);
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106 }
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107
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108 public static byte[] encrypt(byte[] cleartext, String secret) throws Exception {
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109 byte[] salt = new byte[SALT_SIZE];
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110 byte[] ciphertext = Encryptor.encrypt(salt, ITERATIONS, secret, cleartext);
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111 byte[] complete = new byte[salt.length + ciphertext.length];
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112 System.arraycopy(salt, 0, complete, 0, salt.length);
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113 System.arraycopy(ciphertext, 0, complete, salt.length, ciphertext.length);
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114 Arrays.fill(salt, (byte) 0x00);
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115 Arrays.fill(ciphertext, (byte) 0x00);
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116 return complete;
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117 }
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118
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119 public static byte[] decrypt(byte[] saltAndCiphertext, String secret) throws Exception {
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120 try {
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121 byte[] salt = new byte[SALT_SIZE];
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122 byte[] ciphertext = new byte[saltAndCiphertext.length - salt.length];
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123 System.arraycopy(saltAndCiphertext, 0, salt, 0, salt.length);
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124 System.arraycopy(saltAndCiphertext, salt.length, ciphertext, 0, ciphertext.length);
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125 return Encryptor.decrypt(salt, ITERATIONS, secret, ciphertext);
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126 }
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127 catch (Exception e) {
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128 Log.d("decrypt", "Could not decrypt with new method", e);
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129 // We might be using the old encryption method.
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130 return cipher(Cipher.DECRYPT_MODE, saltAndCiphertext, secret.getBytes());
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131 }
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132 }
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133
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134 public static byte[] getEncodedPrivate(PrivateKey pk, String secret) throws Exception {
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135 final byte[] encoded = pk.getEncoded();
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136
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137 if (secret == null || secret.length() == 0) {
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138 return encoded;
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139 }
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140
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141 return encrypt(pk.getEncoded(), secret);
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142 }
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143
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144 public static PrivateKey decodePrivate(byte[] encoded, String keyType) throws NoSuchAlgorithmException, InvalidKeySpecException {
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145 PKCS8EncodedKeySpec privKeySpec = new PKCS8EncodedKeySpec(encoded);
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146 KeyFactory kf = KeyFactory.getInstance(keyType);
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147 return kf.generatePrivate(privKeySpec);
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148 }
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149
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150 public static PrivateKey decodePrivate(byte[] encoded, String keyType, String secret) throws Exception {
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151 if (secret != null && secret.length() > 0)
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152 return decodePrivate(decrypt(encoded, secret), keyType);
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153 else
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154 return decodePrivate(encoded, keyType);
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155 }
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156
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157 public static PublicKey decodePublic(byte[] encoded, String keyType) throws NoSuchAlgorithmException, InvalidKeySpecException {
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158 X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(encoded);
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159 KeyFactory kf = KeyFactory.getInstance(keyType);
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160 return kf.generatePublic(pubKeySpec);
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161 }
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162
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163 static String getAlgorithmForOid(String oid) throws NoSuchAlgorithmException {
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164 if ("1.2.840.10045.2.1".equals(oid)) {
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165 return "EC";
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166 }
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167 else if ("1.2.840.113549.1.1.1".equals(oid)) {
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168 return "RSA";
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169 }
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170 else if ("1.2.840.10040.4.1".equals(oid)) {
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171 return "DSA";
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172 }
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173 else {
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174 throw new NoSuchAlgorithmException("Unknown algorithm OID " + oid);
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175 }
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176 }
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177
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178 static String getOidFromPkcs8Encoded(byte[] encoded) throws NoSuchAlgorithmException {
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179 if (encoded == null) {
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180 throw new NoSuchAlgorithmException("encoding is null");
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181 }
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182
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183 try {
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184 SimpleDERReader reader = new SimpleDERReader(encoded);
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185 reader.resetInput(reader.readSequenceAsByteArray());
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186 reader.readInt();
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187 reader.resetInput(reader.readSequenceAsByteArray());
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188 return reader.readOid();
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189 }
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190 catch (IOException e) {
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191 Log.w(TAG, "Could not read OID", e);
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192 throw new NoSuchAlgorithmException("Could not read key", e);
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193 }
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194 }
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195
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196 public static KeyPair recoverKeyPair(byte[] encoded) throws NoSuchAlgorithmException,
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197 InvalidKeySpecException {
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198 final String algo = getAlgorithmForOid(getOidFromPkcs8Encoded(encoded));
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199 final KeySpec privKeySpec = new PKCS8EncodedKeySpec(encoded);
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200 final KeyFactory kf = KeyFactory.getInstance(algo);
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201 final PrivateKey priv = kf.generatePrivate(privKeySpec);
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202 return new KeyPair(recoverPublicKey(kf, priv), priv);
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203 }
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204
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205
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206 static PublicKey recoverPublicKey(KeyFactory kf, PrivateKey priv)
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207 throws NoSuchAlgorithmException, InvalidKeySpecException {
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208 if (priv instanceof RSAPrivateCrtKey) {
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209 RSAPrivateCrtKey rsaPriv = (RSAPrivateCrtKey) priv;
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210 return kf.generatePublic(new RSAPublicKeySpec(rsaPriv.getModulus(), rsaPriv
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211 .getPublicExponent()));
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212 }
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213 else if (priv instanceof DSAPrivateKey) {
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214 DSAPrivateKey dsaPriv = (DSAPrivateKey) priv;
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215 DSAParams params = dsaPriv.getParams();
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216 // Calculate public key Y
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217 BigInteger y = params.getG().modPow(dsaPriv.getX(), params.getP());
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218 return kf.generatePublic(new DSAPublicKeySpec(y, params.getP(), params.getQ(), params
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219 .getG()));
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220 }
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221 else if (priv instanceof ECPrivateKey) {
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222 ECPrivateKey ecPriv = (ECPrivateKey) priv;
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223 ECParameterSpec params = ecPriv.getParams();
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224 // Calculate public key Y
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225 ECPoint generator = params.getGenerator();
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226 BigInteger[] wCoords = EcCore.multiplyPointA(new BigInteger[] { generator.getAffineX(),
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227 generator.getAffineY()
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228 }, ecPriv.getS(), params);
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229 ECPoint w = new ECPoint(wCoords[0], wCoords[1]);
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230 return kf.generatePublic(new ECPublicKeySpec(w, params));
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231 }
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232 else {
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233 throw new NoSuchAlgorithmException("Key type must be RSA, DSA, or EC");
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234 }
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235 }
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236
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237 /*
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238 * OpenSSH compatibility methods
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239 */
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240
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241 public static String convertToOpenSSHFormat(PublicKey pk, String origNickname) throws IOException, InvalidKeyException {
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242 String nickname = origNickname;
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243
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244 if (nickname == null)
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245 nickname = "connectbot@android";
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246
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247 if (pk instanceof RSAPublicKey) {
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248 String data = "ssh-rsa ";
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249 data += String.valueOf(Base64.encode(RSASHA1Verify.encodeSSHRSAPublicKey((RSAPublicKey) pk)));
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250 return data + " " + nickname;
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251 }
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252 else if (pk instanceof DSAPublicKey) {
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253 String data = "ssh-dss ";
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254 data += String.valueOf(Base64.encode(DSASHA1Verify.encodeSSHDSAPublicKey((DSAPublicKey) pk)));
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255 return data + " " + nickname;
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256 }
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257 else if (pk instanceof ECPublicKey) {
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258 ECPublicKey ecPub = (ECPublicKey) pk;
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259 String keyType = ECDSASHA2Verify.getCurveName(ecPub.getParams().getCurve().getField().getFieldSize());
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260 String keyData = String.valueOf(Base64.encode(ECDSASHA2Verify.encodeSSHECDSAPublicKey(ecPub)));
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261 return ECDSASHA2Verify.ECDSA_SHA2_PREFIX + keyType + " " + keyData + " " + nickname;
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262 }
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263
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264 throw new InvalidKeyException("Unknown key type");
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265 }
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266
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267 /*
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268 * OpenSSH compatibility methods
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269 */
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270
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271 /**
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272 * @param pair
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273 * @return OpenSSH-encoded pubkey
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274 */
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275 public static byte[] extractOpenSSHPublic(KeyPair pair) {
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276 try {
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277 PublicKey pubKey = pair.getPublic();
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278
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279 if (pubKey instanceof RSAPublicKey) {
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280 return RSASHA1Verify.encodeSSHRSAPublicKey((RSAPublicKey) pair.getPublic());
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281 }
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282 else if (pubKey instanceof DSAPublicKey) {
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283 return DSASHA1Verify.encodeSSHDSAPublicKey((DSAPublicKey) pair.getPublic());
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284 }
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285 else if (pubKey instanceof ECPublicKey) {
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286 return ECDSASHA2Verify.encodeSSHECDSAPublicKey((ECPublicKey) pair.getPublic());
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287 }
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288 else {
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289 return null;
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290 }
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291 }
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292 catch (IOException e) {
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293 return null;
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294 }
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295 }
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296
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297 public static String exportPEM(PrivateKey key, String secret) throws NoSuchAlgorithmException, InvalidParameterSpecException, NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException, InvalidKeySpecException, IllegalBlockSizeException, IOException {
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298 StringBuilder sb = new StringBuilder();
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299 byte[] data = key.getEncoded();
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300 sb.append(PKCS8_START);
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301 sb.append('\n');
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302
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303 if (secret != null) {
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304 byte[] salt = new byte[8];
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305 SecureRandom random = new SecureRandom();
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306 random.nextBytes(salt);
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307 PBEParameterSpec defParams = new PBEParameterSpec(salt, 1);
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308 AlgorithmParameters params = AlgorithmParameters.getInstance(key.getAlgorithm());
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309 params.init(defParams);
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310 PBEKeySpec pbeSpec = new PBEKeySpec(secret.toCharArray());
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311 SecretKeyFactory keyFact = SecretKeyFactory.getInstance(key.getAlgorithm());
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312 Cipher cipher = Cipher.getInstance(key.getAlgorithm());
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313 cipher.init(Cipher.WRAP_MODE, keyFact.generateSecret(pbeSpec), params);
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314 byte[] wrappedKey = cipher.wrap(key);
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315 EncryptedPrivateKeyInfo pinfo = new EncryptedPrivateKeyInfo(params, wrappedKey);
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316 data = pinfo.getEncoded();
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317 sb.append("Proc-Type: 4,ENCRYPTED\n");
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318 sb.append("DEK-Info: DES-EDE3-CBC,");
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319 sb.append(encodeHex(salt));
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320 sb.append("\n\n");
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321 }
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322
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323 int i = sb.length();
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324 sb.append(Base64.encode(data));
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325
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326 for (i += 63; i < sb.length(); i += 64) {
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327 sb.insert(i, "\n");
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328 }
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329
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330 sb.append('\n');
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331 sb.append(PKCS8_END);
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332 sb.append('\n');
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333 return sb.toString();
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334 }
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335
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336 private static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4', '5', '6',
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337 '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
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338 };
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339 protected static String encodeHex(byte[] bytes) {
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340 final char[] hex = new char[bytes.length * 2];
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341 int i = 0;
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342
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343 for (byte b : bytes) {
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344 hex[i++] = HEX_DIGITS[(b >> 4) & 0x0f];
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345 hex[i++] = HEX_DIGITS[b & 0x0f];
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346 }
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347
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348 return String.valueOf(hex);
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349 }
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350
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351 public static String getPubkeyString(PubkeyBean pubkey) {
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352 try {
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353 PublicKey pk = decodePublic(pubkey.getPublicKey(), pubkey.getType());
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354 return convertToOpenSSHFormat(pk, pubkey.getNickname());
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355 }
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356 catch (Exception e) {
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357 e.printStackTrace();
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358 }
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359
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360 return null;
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361 }
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362
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363 public static String getPrivkeyString(PubkeyBean pubkey, String passphrase) {
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364 String data = null;
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365 boolean imported = PubkeyDatabase.KEY_TYPE_IMPORTED.equals(pubkey.getType());
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366
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367 if (imported)
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368 try {
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369 data = new String(pubkey.getPrivateKey());
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370 }
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371 catch (Exception e) {
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372 e.printStackTrace();
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373 }
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374 else {
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375 try {
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376 PrivateKey pk = null;
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377
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378 if (passphrase == null)
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379 pk = decodePrivate(pubkey.getPrivateKey(), pubkey.getType());
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380 else
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381 pk = decodePrivate(pubkey.getPrivateKey(), pubkey.getType(), passphrase);
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382
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383 data = exportPEM(pk, passphrase);
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384 }
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385 catch (Exception e) {
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386 e.printStackTrace();
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387 }
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388 }
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389
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390 return data;
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391 }
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392 }
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