RSA公鑰驗證簽名（Java版）

RSA簽名驗證，使用公鑰驗證簽名是否正确，含SHA1,SHA256

需要依賴

commons-codec

<dependency>
	<groupId>commons-codec</groupId>
    <artifactId>commons-codec</artifactId>
    <version>1.11</version>
</dependency>
           

完整代碼如下：

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

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;
import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.spec.X509EncodedKeySpec;

/**
 * RSA簽名驗證，使用公鑰驗證簽名是否正确，含SHA1,SHA256
 *
 * @author tanghc
 */
public class RsaSignUtil {

    public static final String SIGN_ALGORITHMS = "SHA1WithRSA";
    public static final String SIGN_SHA256RSA_ALGORITHMS = "SHA256WithRSA";
    private static final int DEFAULT_BUFFER_SIZE = 8192;

    public enum SignType {
        RSA, RSA2
    }

    /**
     * rsa公鑰驗簽
     *
     * @param content   驗證内容
     * @param sign      簽名串
     * @param publicKey 公鑰
     * @param charset   字元集
     * @param signType  簽名類型,RSA:SHA1WithRSA, RSA2:SHA256WithRSA
     * @return true，簽名正确
     */
    public static boolean rsaCheck(String content, String sign, String publicKey, String charset, SignType signType) {
        if (SignType.RSA == signType) {
            return rsaCheckContent(content, sign, publicKey, charset);
        } else if (SignType.RSA2 == signType) {
            return rsa256CheckContent(content, sign, publicKey, charset);
        } else {
            throw new RuntimeException("Sign Type is Not Support : signType=" + signType);
        }
    }

    public static boolean rsa256CheckContent(String content, String sign, String publicKey, String charset) {
        try {
            PublicKey pubKey = getPublicKeyFromX509("RSA", new ByteArrayInputStream(publicKey.getBytes()));
            java.security.Signature signature = java.security.Signature.getInstance(SIGN_SHA256RSA_ALGORITHMS);
            signature.initVerify(pubKey);
            if (charset == null || "".equals(charset)) {
                signature.update(content.getBytes());
            } else {
                signature.update(content.getBytes(charset));
            }
            return signature.verify(Base64.decodeBase64(sign.getBytes()));
        } catch (Exception e) {
            throw new RuntimeException("RSAcontent = " + content + ",sign=" + sign + ",charset = " + charset, e);
        }
    }

    public static boolean rsaCheckContent(String content, String sign, String publicKey,
                                          String charset) {
        try {
            PublicKey pubKey = getPublicKeyFromX509("RSA",
                    new ByteArrayInputStream(publicKey.getBytes()));

            java.security.Signature signature = java.security.Signature
                    .getInstance(SIGN_ALGORITHMS);

            signature.initVerify(pubKey);

            if (charset == null || "".equals(charset)) {
                signature.update(content.getBytes());
            } else {
                signature.update(content.getBytes(charset));
            }

            return signature.verify(Base64.decodeBase64(sign.getBytes()));
        } catch (Exception e) {
            throw new RuntimeException(
                    "RSAcontent = " + content + ",sign=" + sign + ",charset = " + charset, e);
        }
    }

    public static PublicKey getPublicKeyFromX509(String algorithm,
                                                 InputStream ins) throws Exception {
        KeyFactory keyFactory = KeyFactory.getInstance(algorithm);

        StringWriter writer = new StringWriter();
        io(new InputStreamReader(ins), writer, -1);

        byte[] encodedKey = writer.toString().getBytes();

        encodedKey = Base64.decodeBase64(encodedKey);

        return keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
    }

    private static void io(Reader in, Writer out, int bufferSize) throws IOException {
        if (bufferSize == -1) {
            bufferSize = DEFAULT_BUFFER_SIZE >> 1;
        }

        char[] buffer = new char[bufferSize];
        int amount;

        while ((amount = in.read(buffer)) >= 0) {
            out.write(buffer, 0, amount);
        }
    }

}
           

調用

rsaCheck

方法即可。