--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/src/main/java/ch/ethz/ssh2/crypto/PEMDecoder.java	Thu Dec 03 11:23:55 2015 -0800
@@ -0,0 +1,444 @@
+
+package ch.ethz.ssh2.crypto;
+
+import java.io.BufferedReader;
+import java.io.CharArrayReader;
+import java.io.IOException;
+import java.math.BigInteger;
+import java.security.DigestException;
+import java.security.KeyFactory;
+import java.security.KeyPair;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.security.PrivateKey;
+import java.security.PublicKey;
+import java.security.spec.DSAPrivateKeySpec;
+import java.security.spec.DSAPublicKeySpec;
+import java.security.spec.ECParameterSpec;
+import java.security.spec.ECPoint;
+import java.security.spec.ECPrivateKeySpec;
+import java.security.spec.ECPublicKeySpec;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.KeySpec;
+import java.security.spec.RSAPrivateCrtKeySpec;
+import java.security.spec.RSAPrivateKeySpec;
+import java.security.spec.RSAPublicKeySpec;
+
+import ch.ethz.ssh2.crypto.cipher.AES;
+import ch.ethz.ssh2.crypto.cipher.BlockCipher;
+import ch.ethz.ssh2.crypto.cipher.CBCMode;
+import ch.ethz.ssh2.crypto.cipher.DES;
+import ch.ethz.ssh2.crypto.cipher.DESede;
+import ch.ethz.ssh2.signature.ECDSASHA2Verify;
+
+/**
+ * PEM Support.
+ *
+ * @author Christian Plattner, plattner@trilead.com
+ * @version $Id: PEMDecoder.java,v 1.2 2008/04/01 12:38:09 cplattne Exp $
+ */
+public class PEMDecoder {
+    public static final int PEM_RSA_PRIVATE_KEY = 1;
+    public static final int PEM_DSA_PRIVATE_KEY = 2;
+    public static final int PEM_EC_PRIVATE_KEY = 3;
+
+    private static final int hexToInt(char c) {
+        if ((c >= 'a') && (c <= 'f')) {
+            return (c - 'a') + 10;
+        }
+
+        if ((c >= 'A') && (c <= 'F')) {
+            return (c - 'A') + 10;
+        }
+
+        if ((c >= '0') && (c <= '9')) {
+            return (c - '0');
+        }
+
+        throw new IllegalArgumentException("Need hex char");
+    }
+
+    private static byte[] hexToByteArray(String hex) {
+        if (hex == null)
+            throw new IllegalArgumentException("null argument");
+
+        if ((hex.length() % 2) != 0)
+            throw new IllegalArgumentException("Uneven string length in hex encoding.");
+
+        byte decoded[] = new byte[hex.length() / 2];
+
+        for (int i = 0; i < decoded.length; i++) {
+            int hi = hexToInt(hex.charAt(i * 2));
+            int lo = hexToInt(hex.charAt((i * 2) + 1));
+            decoded[i] = (byte)(hi * 16 + lo);
+        }
+
+        return decoded;
+    }
+
+    private static byte[] generateKeyFromPasswordSaltWithMD5(byte[] password, byte[] salt, int keyLen)
+    throws IOException {
+        if (salt.length < 8)
+            throw new IllegalArgumentException("Salt needs to be at least 8 bytes for key generation.");
+
+        MessageDigest md5;
+
+        try {
+            md5 = MessageDigest.getInstance("MD5");
+        }
+        catch (NoSuchAlgorithmException e) {
+            throw new IllegalArgumentException("VM does not support MD5", e);
+        }
+
+        byte[] key = new byte[keyLen];
+        byte[] tmp = new byte[md5.getDigestLength()];
+
+        while (true) {
+            md5.update(password, 0, password.length);
+            md5.update(salt, 0, 8); // ARGH we only use the first 8 bytes of the
+            // salt in this step.
+            // This took me two hours until I got AES-xxx running.
+            int copy = (keyLen < tmp.length) ? keyLen : tmp.length;
+
+            try {
+                md5.digest(tmp, 0, tmp.length);
+            }
+            catch (DigestException e) {
+                IOException ex = new IOException("could not digest password");
+                ex.initCause(e);
+                throw ex;
+            }
+
+            System.arraycopy(tmp, 0, key, key.length - keyLen, copy);
+            keyLen -= copy;
+
+            if (keyLen == 0)
+                return key;
+
+            md5.update(tmp, 0, tmp.length);
+        }
+    }
+
+    private static byte[] removePadding(byte[] buff, int blockSize) throws IOException {
+        /* Removes RFC 1423/PKCS #7 padding */
+        int rfc_1423_padding = buff[buff.length - 1] & 0xff;
+
+        if ((rfc_1423_padding < 1) || (rfc_1423_padding > blockSize))
+            throw new IOException("Decrypted PEM has wrong padding, did you specify the correct password?");
+
+        for (int i = 2; i <= rfc_1423_padding; i++) {
+            if (buff[buff.length - i] != rfc_1423_padding)
+                throw new IOException("Decrypted PEM has wrong padding, did you specify the correct password?");
+        }
+
+        byte[] tmp = new byte[buff.length - rfc_1423_padding];
+        System.arraycopy(buff, 0, tmp, 0, buff.length - rfc_1423_padding);
+        return tmp;
+    }
+
+    public static final PEMStructure parsePEM(char[] pem) throws IOException {
+        PEMStructure ps = new PEMStructure();
+        String line = null;
+        BufferedReader br = new BufferedReader(new CharArrayReader(pem));
+        String endLine = null;
+
+        while (true) {
+            line = br.readLine();
+
+            if (line == null)
+                throw new IOException("Invalid PEM structure, '-----BEGIN...' missing");
+
+            line = line.trim();
+
+            if (line.startsWith("-----BEGIN DSA PRIVATE KEY-----")) {
+                endLine = "-----END DSA PRIVATE KEY-----";
+                ps.pemType = PEM_DSA_PRIVATE_KEY;
+                break;
+            }
+
+            if (line.startsWith("-----BEGIN RSA PRIVATE KEY-----")) {
+                endLine = "-----END RSA PRIVATE KEY-----";
+                ps.pemType = PEM_RSA_PRIVATE_KEY;
+                break;
+            }
+
+            if (line.startsWith("-----BEGIN EC PRIVATE KEY-----")) {
+                endLine = "-----END EC PRIVATE KEY-----";
+                ps.pemType = PEM_EC_PRIVATE_KEY;
+                break;
+            }
+        }
+
+        while (true) {
+            line = br.readLine();
+
+            if (line == null)
+                throw new IOException("Invalid PEM structure, " + endLine + " missing");
+
+            line = line.trim();
+            int sem_idx = line.indexOf(':');
+
+            if (sem_idx == -1)
+                break;
+
+            String name = line.substring(0, sem_idx + 1);
+            String value = line.substring(sem_idx + 1);
+            String values[] = value.split(",");
+
+            for (int i = 0; i < values.length; i++)
+                values[i] = values[i].trim();
+
+            // Proc-Type: 4,ENCRYPTED
+            // DEK-Info: DES-EDE3-CBC,579B6BE3E5C60483
+
+            if ("Proc-Type:".equals(name)) {
+                ps.procType = values;
+                continue;
+            }
+
+            if ("DEK-Info:".equals(name)) {
+                ps.dekInfo = values;
+                continue;
+            }
+
+            /* Ignore line */
+        }
+
+        StringBuffer keyData = new StringBuffer();
+
+        while (true) {
+            if (line == null)
+                throw new IOException("Invalid PEM structure, " + endLine + " missing");
+
+            line = line.trim();
+
+            if (line.startsWith(endLine))
+                break;
+
+            keyData.append(line);
+            line = br.readLine();
+        }
+
+        char[] pem_chars = new char[keyData.length()];
+        keyData.getChars(0, pem_chars.length, pem_chars, 0);
+        ps.data = Base64.decode(pem_chars);
+
+        if (ps.data.length == 0)
+            throw new IOException("Invalid PEM structure, no data available");
+
+        return ps;
+    }
+
+    private static final void decryptPEM(PEMStructure ps, byte[] pw) throws IOException {
+        if (ps.dekInfo == null)
+            throw new IOException("Broken PEM, no mode and salt given, but encryption enabled");
+
+        if (ps.dekInfo.length != 2)
+            throw new IOException("Broken PEM, DEK-Info is incomplete!");
+
+        String algo = ps.dekInfo[0];
+        byte[] salt = hexToByteArray(ps.dekInfo[1]);
+        BlockCipher bc = null;
+
+        if (algo.equals("DES-EDE3-CBC")) {
+            DESede des3 = new DESede();
+            des3.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 24));
+            bc = new CBCMode(des3, salt, false);
+        }
+        else if (algo.equals("DES-CBC")) {
+            DES des = new DES();
+            des.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 8));
+            bc = new CBCMode(des, salt, false);
+        }
+        else if (algo.equals("AES-128-CBC")) {
+            AES aes = new AES();
+            aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 16));
+            bc = new CBCMode(aes, salt, false);
+        }
+        else if (algo.equals("AES-192-CBC")) {
+            AES aes = new AES();
+            aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 24));
+            bc = new CBCMode(aes, salt, false);
+        }
+        else if (algo.equals("AES-256-CBC")) {
+            AES aes = new AES();
+            aes.init(false, generateKeyFromPasswordSaltWithMD5(pw, salt, 32));
+            bc = new CBCMode(aes, salt, false);
+        }
+        else {
+            throw new IOException("Cannot decrypt PEM structure, unknown cipher " + algo);
+        }
+
+        if ((ps.data.length % bc.getBlockSize()) != 0)
+            throw new IOException("Invalid PEM structure, size of encrypted block is not a multiple of "
+                                  + bc.getBlockSize());
+
+        /* Now decrypt the content */
+        byte[] dz = new byte[ps.data.length];
+
+        for (int i = 0; i < ps.data.length / bc.getBlockSize(); i++) {
+            bc.transformBlock(ps.data, i * bc.getBlockSize(), dz, i * bc.getBlockSize());
+        }
+
+        /* Now check and remove RFC 1423/PKCS #7 padding */
+        dz = removePadding(dz, bc.getBlockSize());
+        ps.data = dz;
+        ps.dekInfo = null;
+        ps.procType = null;
+    }
+
+    public static final boolean isPEMEncrypted(PEMStructure ps) throws IOException {
+        if (ps.procType == null)
+            return false;
+
+        if (ps.procType.length != 2)
+            throw new IOException("Unknown Proc-Type field.");
+
+        if ("4".equals(ps.procType[0]) == false)
+            throw new IOException("Unknown Proc-Type field (" + ps.procType[0] + ")");
+
+        if ("ENCRYPTED".equals(ps.procType[1]))
+            return true;
+
+        return false;
+    }
+
+    public static KeyPair decode(char[] pem, String password) throws IOException {
+        PEMStructure ps = parsePEM(pem);
+        return decode(ps, password);
+    }
+
+    public static KeyPair decode(PEMStructure ps, String password) throws IOException {
+        if (isPEMEncrypted(ps)) {
+            if (password == null)
+                throw new IOException("PEM is encrypted, but no password was specified");
+
+            decryptPEM(ps, password.getBytes("ISO-8859-1"));
+        }
+
+        if (ps.pemType == PEM_DSA_PRIVATE_KEY) {
+            SimpleDERReader dr = new SimpleDERReader(ps.data);
+            byte[] seq = dr.readSequenceAsByteArray();
+
+            if (dr.available() != 0)
+                throw new IOException("Padding in DSA PRIVATE KEY DER stream.");
+
+            dr.resetInput(seq);
+            BigInteger version = dr.readInt();
+
+            if (version.compareTo(BigInteger.ZERO) != 0)
+                throw new IOException("Wrong version (" + version + ") in DSA PRIVATE KEY DER stream.");
+
+            BigInteger p = dr.readInt();
+            BigInteger q = dr.readInt();
+            BigInteger g = dr.readInt();
+            BigInteger y = dr.readInt();
+            BigInteger x = dr.readInt();
+
+            if (dr.available() != 0)
+                throw new IOException("Padding in DSA PRIVATE KEY DER stream.");
+
+            DSAPrivateKeySpec privSpec = new DSAPrivateKeySpec(x, p, q, g);
+            DSAPublicKeySpec pubSpec = new DSAPublicKeySpec(y, p, q, g);
+            return generateKeyPair("DSA", privSpec, pubSpec);
+        }
+
+        if (ps.pemType == PEM_RSA_PRIVATE_KEY) {
+            SimpleDERReader dr = new SimpleDERReader(ps.data);
+            byte[] seq = dr.readSequenceAsByteArray();
+
+            if (dr.available() != 0)
+                throw new IOException("Padding in RSA PRIVATE KEY DER stream.");
+
+            dr.resetInput(seq);
+            BigInteger version = dr.readInt();
+
+            if ((version.compareTo(BigInteger.ZERO) != 0) && (version.compareTo(BigInteger.ONE) != 0))
+                throw new IOException("Wrong version (" + version + ") in RSA PRIVATE KEY DER stream.");
+
+            BigInteger n = dr.readInt();
+            BigInteger e = dr.readInt();
+            BigInteger d = dr.readInt();
+            // TODO: is this right?
+            BigInteger primeP = dr.readInt();
+            BigInteger primeQ = dr.readInt();
+            BigInteger expP = dr.readInt();
+            BigInteger expQ = dr.readInt();
+            BigInteger coeff = dr.readInt();
+            RSAPrivateKeySpec privSpec = new RSAPrivateCrtKeySpec(n, e, d, primeP, primeQ, expP, expQ, coeff);
+            RSAPublicKeySpec pubSpec = new RSAPublicKeySpec(n, e);
+            return generateKeyPair("RSA", privSpec, pubSpec);
+        }
+
+        if (ps.pemType == PEM_EC_PRIVATE_KEY) {
+            SimpleDERReader dr = new SimpleDERReader(ps.data);
+            byte[] seq = dr.readSequenceAsByteArray();
+
+            if (dr.available() != 0)
+                throw new IOException("Padding in EC PRIVATE KEY DER stream.");
+
+            dr.resetInput(seq);
+            BigInteger version = dr.readInt();
+
+            if ((version.compareTo(BigInteger.ONE) != 0))
+                throw new IOException("Wrong version (" + version + ") in EC PRIVATE KEY DER stream.");
+
+            byte[] privateBytes = dr.readOctetString();
+            String curveOid = null;
+            byte[] publicBytes = null;
+
+            while (dr.available() > 0) {
+                int type = dr.readConstructedType();
+                SimpleDERReader cr = dr.readConstructed();
+
+                switch (type) {
+                    case 0:
+                        curveOid = cr.readOid();
+                        break;
+
+                    case 1:
+                        publicBytes = cr.readOctetString();
+                        break;
+                }
+            }
+
+            ECParameterSpec params = ECDSASHA2Verify.getCurveForOID(curveOid);
+
+            if (params == null)
+                throw new IOException("invalid OID");
+
+            BigInteger s = new BigInteger(privateBytes);
+            byte[] publicBytesSlice = new byte[publicBytes.length - 1];
+            System.arraycopy(publicBytes, 1, publicBytesSlice, 0, publicBytesSlice.length);
+            ECPoint w = ECDSASHA2Verify.decodeECPoint(publicBytesSlice, params.getCurve());
+            ECPrivateKeySpec privSpec = new ECPrivateKeySpec(s, params);
+            ECPublicKeySpec pubSpec = new ECPublicKeySpec(w, params);
+            return generateKeyPair("EC", privSpec, pubSpec);
+        }
+
+        throw new IOException("PEM problem: it is of unknown type");
+    }
+
+    /**
+     * Generate a {@code KeyPair} given an {@code algorithm} and {@code KeySpec}.
+     */
+    private static KeyPair generateKeyPair(String algorithm, KeySpec privSpec, KeySpec pubSpec)
+    throws IOException {
+        try {
+            final KeyFactory kf = KeyFactory.getInstance(algorithm);
+            final PublicKey pubKey = kf.generatePublic(pubSpec);
+            final PrivateKey privKey = kf.generatePrivate(privSpec);
+            return new KeyPair(pubKey, privKey);
+        }
+        catch (NoSuchAlgorithmException ex) {
+            IOException ioex = new IOException();
+            ioex.initCause(ex);
+            throw ioex;
+        }
+        catch (InvalidKeySpecException ex) {
+            IOException ioex = new IOException("invalid keyspec");
+            ioex.initCause(ex);
+            throw ioex;
+        }
+    }
+}