com.spotify.sshagentproxy.RSA.java Source code

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Here is the source code for com.spotify.sshagentproxy.RSA.java

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/*-
 * -\-\-
 * ssh-agent-proxy
 * --
 * Copyright (C) 2016 Spotify AB
 * --
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * -/-/-
 */

/**
 * Copyright (c) 2015 Spotify AB.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.spotify.sshagentproxy;

import com.google.common.base.Objects;

import org.apache.commons.codec.binary.Base64;

import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.RSAPublicKeySpec;
import java.util.Iterator;

class RSA {

    static final String RSA_LABEL = "ssh-rsa";

    private RSA() {
    }

    /**
     * Create an {@link RSAPublicKey} from bytes.
     * @param key Array of bytes representing RSA public key.
     * @return {@link RSAPublicKey}
     * @throws InvalidKeyException
     * @throws NoSuchAlgorithmException
     * @throws InvalidKeySpecException
     */
    static RSAPublicKey from(final byte[] key)
            throws InvalidKeyException, NoSuchAlgorithmException, InvalidKeySpecException {

        final String s = new String(key);
        final byte[] encoded;
        final String decoded;
        if (s.startsWith(RSA_LABEL)) {
            decoded = s.split(" ")[1];
            encoded = Base64.decodeBase64(decoded);
        } else {
            encoded = key;
            decoded = Base64.encodeBase64String(key);
        }

        final Iterator<byte[]> fields = new ByteIterator(encoded);
        final String sigType = new String(fields.next());
        if (!sigType.equals(RSA_LABEL)) {
            throw new RuntimeException(String.format("Unknown key type %s. This code currently only supports %s.",
                    sigType, RSA_LABEL));
        }

        final RSAPublicKeySpec keySpec = TraditionalKeyParser.parsePemPublicKey(RSA_LABEL + " " + decoded + " ");
        final KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        return (RSAPublicKey) keyFactory.generatePublic(keySpec);
    }

    @Override
    public String toString() {
        return Objects.toStringHelper(this).toString();
    }
}