android支付寶 KeyFactory PrivateKey

public class SignUtils {

private static final String ALGORITHM = "RSA";

private static final String SIGN_ALGORITHMS = "SHA1WithRSA";

private static final String DEFAULT_CHARSET = "UTF-8";

public static String sign(String content, String privateKey) {

try {

PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(

Base64.decode(privateKey));

KeyFactory keyf = KeyFactory.getInstance(ALGORITHM);

PrivateKey priKey = keyf.generatePrivate(priPKCS8);

java.security.Signature signature = java.security.Signature

.getInstance(SIGN_ALGORITHMS);

signature.initSign(priKey);

signature.update(content.getBytes(DEFAULT_CHARSET));

byte[] signed = signature.sign();

return Base64.encode(signed);

} catch (Exception e) {

e.printStackTrace();

}

return null;

}

}

第一開始，調用KeyFactory keyf = KeyFactory.getInstance(ALGORITHM);報錯。以下：

java.security.spec.InvalidKeySpecException: java.lang.RuntimeException: error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag

KeyFactory keyf = KeyFactory.getInstance(ALGORITHM, "BC");  加入了「BC」報以下錯誤：

com.android.org.bouncycastle.jcajce.provider.asymmetric.util.ExtendedInvalidKeySpecException: unable to process key spec: java.lang.ClassCastException: com.android.org.bouncycastle.asn1.DLSequence cannot be cast to com.android.org.bouncycastle.asn1.ASN1Integer

最終由於傳入私鑰錯誤。須要從新生成私鑰：

私鑰的格式大約是這樣：