Java RSA Key Sizes

Peter Y. :

I am trying to learn how to sign messages using the RSA algorithm with SHA256 in Java. When I generated a 2048-bit KeyPair, I found that both the public and private key were 294 bytes. Here is my code for finding the size of the keys:

import java.security.*;

public class RSATesting
{    
    public static void main(String[] args) throws Exception
    {
        KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");
        generator.initialize(2048, new SecureRandom());
        KeyPair pair = generator.generateKeyPair();

        byte[] publicKeyBytes=pair.getPublic().getEncoded();
        System.out.println(publicKeyBytes.length);
        byte[] privateKeyBytes=pair.getPublic().getEncoded();
        System.out.println(privateKeyBytes.length);
    }
}

Why are the keys not 256 bytes?

Thanks

Jakob :

RSA keys aren't like AES keys.

AES keys are some random bytes. RSA keys are numbers. The RSA modulus (N) defines the lenght.

Your key is 294 bytes long, because of getEncoded();. It returns a formatted key and not the real lenght.

Guess you like

Origin http://43.154.161.224:23101/article/api/json?id=358978&siteId=1

Java RSA Key Sizes

Java RSA public and private key encryption tools

and node-rsa java-rsa corresponding public and private key encryption and decryption and generated rsa

Java & PHP RSA key exchange, signature, sign inspection, encryption, decryption

How to load RSA public key from String for signature verification in Java?

Java implements RSA encryption and decryption algorithm public key encryption parameters

Java RSA generated public key private key encoding and Base64 encoding

java file sizes by recursively statistics

java compare two date sizes

Public key algorithm -RSA algorithm

RSA key pair, encryption, decryption

Selection of RSA public key index

How is the RSA public key calculated?

[Java tools] Asymmetric encryption using RSA algorithm serialization save processing public key private key encryption and decryption tools

C # asp.net RSA key format of the Java format conversion (PEM format)

[Java] RSA algorithm - the cornerstone of public key encryption and digital signatures, principle interpretation, code implementation, source code interpretation

Difference between RSA key "BEGIN RSA PRIVATE KEY" and "BEGIN PRIVATE KEY"

-DES-RSA public key encryption

RSA1024 bit private key encryption

So far the longest RSA key cracked?

Solve the problem of "rsa public key not find" in Navicat

Python generates RSA key pair and object serialization

Chapter 9 Public Key Cryptography and RSA (Unfinished)

Chapter 9 Public Key Cryptography and RSA (Unfinished)

Chapter 9 Public Key Cryptography and RSA (Unfinished)

RSA public key length read and write

c# uses RSA public key to decrypt

Unlock the new skill "RSA gets the private key and reports java.security.InvalidKeyException: IOException: algid parse error, not a sequence"

iOS RSA encryption and generation of public key and key pem file

The specific application of RSA public key and private key in practical application