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javarsapemspongycastlepkcs#8

Read encrypted PKCS8 SpongyCastle Java


I am following the code in: https://stackoverflow.com/a/18161536/1753951 but I am getting an Exception in the following line:

FileInputStream fis = new FileInputStream(priv);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int)priv.length()];
dis.readFully(keyBytes);
dis.close();
javax.crypto.EncryptedPrivateKeyInfo encryptPKInfo = new EncryptedPrivateKeyInfo(keyBytes);
//Exception: 
org.apache.harmony.security.asn1.ASN1Exception: Wrong content length

I am trying to read a .key/.pem PKCS8 file which is:

-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK Info: AES-256-CBC,8AFF348907C84F2F6370A216DC0D55D9

1VIjJD3dZ5/wYnIm0mtp8d22RC24yGcY9LXgeHUDbyPJQa8PjupubFqKrpOodvQx
dPfE1F3XeY8oVG42ZfR4287X4V16n++BQCeDiuvyrwacLMAuQz6PFLT4b/Py89Cm
761UZpaWnH0PHfJqB9CHqC+pGAGfRF5vj7UtdNchCwBmo+7gvU5iGyYXNRJ/hPnU
V+8QDzro4kFIMOlDzHaJ3KN1Ftbb9LDjDNE/NShbRrAFAWJMZSY/ZjF8mfqggkoZ
            %%%%%  SKIPPED MOST OF IT %%%%%%%%%%
BMIl0y5XVgPwkApA30EdgV4YAZEJ+wQLnYIZfCklqzvCfyjxHFViVW6d41WNm8bx
wl28v4QJKlnf7KNcmmGwSmjKo7BEASSZ+XVYRu0R6FaE+Job5YzPrtUI+p/kf7et
Y+jUDbZ4BPvB8j2ZscNRs+pJkEXxPt5JKW/oQMQZPlbTtSV5K1IqiuVcRi9TbCzk
nWDSfI/wxt6cK3X9XvyOpOZDCDPchkIhDhCzfitd7fzkM1VBekwsliJwjgc1bwbc
nI4AhQcNb8li7oX1M2osyeR3zF25BDb2A04Zm1lMrWkFrypb24DKkSJxYEH33Gpu
-----END RSA PRIVATE KEY-----

Solution

  • After looking long time for a solution I stumbled with a library that helps me and works on android. Not-Yet-Commons

    http://juliusdavies.ca/commons-ssl/

    FileInputStream in = new FileInputStream( "/path/to/pkcs8_private_key.der" );
    
    PKCS8Key pkcs8 = new PKCS8Key( in, "changeit".toCharArray() );
    
    byte[] decrypted = pkcs8.getDecryptedBytes();
    PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec( decrypted );
    
    // A Java PrivateKey object is born.
    PrivateKey pk = null;
    if ( pkcs8.isDSA() )
    {
       pk = KeyFactory.getInstance( "DSA" ).generatePrivate( spec );
    }
    else if ( pkcs8.isRSA() )
    {
       pk = KeyFactory.getInstance( "RSA" ).generatePrivate( spec );
    }
    // For lazier types (like me):
    pk = pkcs8.getPrivateKey();