Examples with DSAParams com.mindbright.security.pkcs1.DSAParams used on opensource projects

Example 1 with DSAParams

use of com.mindbright.security.pkcs1.DSAParams in project SpringRemote by HaleyWang.

the class X509Certificate method getPublicKey.

public PublicKey getPublicKey() {
    SubjectPublicKeyInfo spki = certificate.tbsCertificate.subjectPublicKeyInfo;
    String alg = spki.algorithm.algorithmName().toUpperCase();
    ASN1DER der = new ASN1DER();
    if (alg.startsWith("RSA")) {
        RSAPublicKey rsa = new RSAPublicKey();
        ByteArrayInputStream ba = new ByteArrayInputStream(spki.subjectPublicKey.getBitArray());
        try {
            der.decode(ba, rsa);
        } catch (Exception e) {
            throw new Error("Internal error decoding SubjectPublicKeyInfo.subjectPublicKey: " + e.getMessage());
        }
        try {
            KeyFactory keyFact = KeyFactory.getInstance("RSA");
            RSAPublicKeySpec pubSpec = new RSAPublicKeySpec(rsa.modulus.getValue(), rsa.publicExponent.getValue());
            return keyFact.generatePublic(pubSpec);
        } catch (Exception e) {
            throw new Error("Error creating RSA key: " + e.getMessage());
        }
    } else if (alg.startsWith("DSA")) {
        DSAPublicKey dsa = new DSAPublicKey();
        ByteArrayInputStream ba = new ByteArrayInputStream(spki.subjectPublicKey.getBitArray());
        try {
            der.decode(ba, dsa);
        } catch (Exception e) {
            throw new Error("Internal error decoding SubjectPublicKeyInfo.subjectPublicKey: " + e.getMessage());
        }
        BigInteger y = dsa.getValue();
        DSAParams dsaParams = (DSAParams) spki.algorithm.parameters.getValue();
        BigInteger p = dsaParams.p.getValue();
        BigInteger q = dsaParams.q.getValue();
        BigInteger g = dsaParams.g.getValue();
        try {
            KeyFactory dsaKeyFact = KeyFactory.getInstance("DSA");
            DSAPublicKeySpec dsaPubSpec = new DSAPublicKeySpec(y, p, q, g);
            return dsaKeyFact.generatePublic(dsaPubSpec);
        } catch (Exception e) {
            throw new Error("Error creating DSA key: " + e.getMessage());
        }
    } else {
        throw new Error("Internal error decoding publicKey: unknown algorithm");
    }
}