public-key-encryption

I only have some very rudimentary theoretical knowledge about RSA. While reading different sources about how to use it in practice, it seemed that PKCS#1 OAEP would be a good thing. For a test implementation, I use Python with PyCrypto. E.g. this is an example using PKCS#1 OAEP. Encrypting using the public key and then decrypting using the private key works fine. E.g. the public can send some data to person X with the private key. From my basic understanding of how RSA works, I thought that I can just interchange the public/private key, i.e. I can use the public key for encrypting and the

I was tasked with writing a small Java console application that involves encryption. I am not familiar with encryption, so I had to do some reading up first. So far the high level requirements given is that AES-256 should be used to generate a one-time key to encrypt a file. After that, the recipient's public key (RSA-2048) should be used to encrypt that AES-256 one-time key. The encrypted file and the encrypted one-time AES-256 key will then be zipped up and send to recipient. From what I understand about encryption and decryption from reading up, apart from the algorithm (RSA, AES, etc),

What opportunities are there for regular app developers (with that I mean, you're not a million dollar content producing company or distribution channel provider, but a regular, small app development company) to secure video/audio content for the app from being saved/distributed. I mention the 'regular developer', because I had seen in the Android core code that Sony had added some code portions into it, in the DRM packages. Let's assume we're not that powerful to talk to Google to include such in their core code. Are there any real secure ways to protect video/audio (as part of an app) on

I have a gpg .key file that is used as passphrase for decrypting a .dat.pgp file. The encrypted .data.pgp file gets successfully decrypted on one server with same .key file using following command cat xxx_gpg.key | /usr/bin/gpg --batch --quiet -o xxx.dat --passphrase-fd O -d xxx.dat.pgp But, when I move same key to another server xxx_gpg.key and run same above command, I get following error - gpg: decryption failed: No secret key EDIT: I find that gpg --list-secret-keys returns some data on server where it works but no results are returned for other server. How can we configure secret key

I've used the following code to convert the public and private key to a string KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA"); keyPairGen.initialize(2048); KeyPair keyPair = keyPairGen.genKeyPair(); PublicKey publicKey = keyPair.getPublic(); PrivateKey privateKey = keyPair.getPrivate(); String publicK = Base64.encodeBase64String(publicKey.getEncoded()); String privateK = Base64.encodeBase64String(privateKey.getEncoded()); Now I'm trying to convert it back to public ad private key PublicKey publicDecoded = Base64.decodeBase64(publicK); I'm getting error of cannot convert from