public-key-encryption

I am trying to encrypt and decrypt the data with RSA 2048. We have one public key and private key and will be using same throughout. but the problem is, when I decrypt, I am getting javax.crypto.BadPaddingException: Data must start with zero File file = new File("C:\\temp-ldi\\pubkey.txt"); FileWriter writer = new FileWriter(file); file.createNewFile(); encryptedText = RSACrypto.encrypt("PLAIN TEXT"); //no argument of pub-key, generate key pair writer.write(new BASE64Encoder().encode(RSACrypto.pubKeyToBytes(RSACrypto.publicKey))); writer.close(); file = new File("C:\\temp-ldi\\privkey.txt");

I have a 1024 bits private key, and use it to generate a public key. Does that automatically mean that my public key also has 1024 encryption? Or can it be of a lesser encryption size? (512, 256...) PS: What i'm mostly interested in, and talking about, is the size of the modulus ("n") in RSA keys. The size is typically 1024 or 2048 bits. But I'm glad to see that this sparked a discussion, and all this is feeding my interest in cryptography. No. The public key in a key pair always matches the private key size, in fact it is derived from the private key. However, with some public key

Please can you suggest any implementation of elliptical curve cryptography to be used on .NET platform? Also if you have used them, can you tell me the recommended curves that should be used? [EDIT] As @FatCat mentioned, its implementation is available in .NET framework 3.5 but that is only available on windows vista. Can you please suggest another way/library to use it? Check out the Bouncy Castle library for C#, it has ECDH and ECDSA. The .NET Framework already includes Diffie-Hellman, which is an elliptic curve crypto algorithm. Look under System.Security.Cryptography.ECDiffieHellmanCng .

I generated a keeper using SecKeyGeneratePair. var publicKeyPtr, privateKeyPtr: Unmanaged<SecKey>? let publicKeyParameters: [String: AnyObject] = [ kSecAttrIsPermanent: true, kSecAttrApplicationTag: "com.example.site.public" ] let privateKeyParameters: [String: AnyObject] = [ kSecAttrIsPermanent: true, kSecAttrApplicationTag: "com.example.site.private" ] let parameters: [String: AnyObject] = [ kSecAttrKeyType: kSecAttrKeyTypeRSA, kSecAttrKeySizeInBits: 2048, kSecPublicKeyAttrs.takeUnretainedValue() as String: publicKeyParameters, kSecPrivateKeyAttrs.takeUnretainedValue() as String:

I am trying to implement ECC algorithm on Android. I am currently using spongy castle to implement it. The key generation cone snippet is as follows : KeyPairGenerator kpg = null; try { kpg = KeyPairGenerator.getInstance("ECIES");// Do i have to do any changes here? } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } ECGenParameterSpec brainpoolP160R1 = new ECGenParameterSpec("brainpoolP160R1"); try { kpg.initialize(brainpoolP160R1); } catch (InvalidAlgorithmParameterException) { } KeyPair kp = kpg.generateKeyPair(); PublicKey publicKey = kp.getPublic(); PrivateKey privateKey = kp

I am trying to sign and verify sign using PKCS#7. I am following book beginning cryptography with java . I have written sample code to sign and verify. When i am trying to attach a signature and write it to a file and then trying to verify i am getting exception (Exception is given below ) I want to know how do we write this signed data to a file ? Do i need to share keystore also to second person who will verify the sign? org.bouncycastle.cms.CMSException: message-digest attribute value does not match calculated value at org.bouncycastle.cms.SignerInformation.doVerify(Unknown Source) at org

Currently I am using apache vfs2 to download files from a sftp. For authentication I use user-name and password. Is there a way to use vfs2 only with public-private-keys and without a password? I think I have use this function,but how? Set it only to "yes"? SftpFileSystemConfigBuilder.getInstance().setStrictHostKeyChecking(options, "no"); This is my current code (snippet): private boolean downloadFile(){ StandardFileSystemManager sysManager = new StandardFileSystemManager(); //download der Datei try { sysManager.init(); FileObject localFile = sysManager.resolveFile(localFilePath); FileObject