Android-Java RSA解密

Question

我需要从一个二进制字符串为 RSA 算法创建一个公钥。

我的代码是：

String pubKey = "tihq/Gk3OUs5NzP+XTRKXBwSxHtB0TWn0RREcpXEtp316tyD9DzKaIbdKexb/mRr";

byte[] keyBytes = Base64.decode(pubKey,Base64.DEFAULT);
//test if is correct: ok
Log.d("response keyBytes",new String(Base64.encode(keyBytes,Base64.DEFAULT)));

KeyFactory keyFactory = KeyFactory.getInstance("RSA");      
X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);

RSAPublicKey publicKey = (RSAPublicKey) keyFactory.generatePublic(spec);
//PublicKey publicKey = (PublicKey) keyFactory.generatePublic(spec);

但我有这个错误：

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

Answer 1

已解决。 问题是我有模数和指数，所以我必须这样做：

String pubKey = "tihq/Gk3OUs5NzP+XTRKXBwSxHtB0TWn0RREcpXEtp316tyD9DzKaIbdKexb/mRr"; //64 caratteri
String exponent = "AQAB";

byte[] keyBytes = Base64.decode(pubKey,Base64.DEFAULT);
byte[] exponentByte = Base64.decode(exponent,Base64.DEFAULT);

KeyFactory keyFactory = KeyFactory.getInstance("RSA");

RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger(keyBytes), new BigInteger(exponentByte));
RSAPublicKey publicKey = (RSAPublicKey) keyFactory.generatePublic(pubKeySpec);