javasecurityrsajcepkcs#8

How to convert a PKCS#8 encoded RSA key into PKCS#1 in Java?

Is it possible to convert a PKCS#8 encoded RSA private key into PKCS#1? I know this can be done easily via openssl, but can it be done in Java?

Solution

  • Use BouncyCastle 1.50 

    PrivateKeyInfo pkInfo = PrivateKeyInfo.getInstance(pkPair.getPrivateKey().getEncodedKey());
ASN1Encodable privateKeyPKCS1ASN1Encodable = pkInfo.parsePrivateKey();
ASN1Primitive privateKeyPKCS1ASN1 = privateKeyPKCS1ASN1Encodable.toASN1Primitive();

byte[] privateKeyPKCS1 = privateKeyPKCS1ASN1.getEncoded();