You can generate a public-private keypair with the genrsa context (the last number is the keylength in bits): openssl genrsa -out keypair.pem 2048 To extract the public part, use the rsa context: openssl rsa -in keypair.pem -pubout -out publickey.crt Finally, convert the original keypair to PKCS#8 format with the pkcs8 context: openssl pkcs8 -topk8 -inform … Read more
Your teacher gave you: Public Key: (10142789312725007, 5) which means n = 10142789312725007 e = 5 where n is the modulus and e is the public exponent. In addition, you’re given Private Key: (10142789312725007, 8114231289041741) meaning that d = 8114231289041741 where d is the decryption exponent that should remain secret. You can “break” RSA by … Read more
Use M2Crypto. Here’s how to verify for RSA and any other algorithm supported by OpenSSL: pem = “””—–BEGIN PUBLIC KEY—– MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDfG4IuFO2h/LdDNmonwGNw5srW nUEWzoBrPRF1NM8LqpOMD45FAPtZ1NmPtHGo0BAS1UsyJEGXx0NPJ8Gw1z+huLrl XnAVX5B4ec6cJfKKmpL/l94WhP2v8F3OGWrnaEX1mLMoxe124Pcfamt0SPCGkeal VvXw13PLINE/YptjkQIDAQAB —–END PUBLIC KEY—–“”” # your example key from M2Crypto import BIO, RSA, EVP bio = BIO.MemoryBuffer(pem) rsa = RSA.load_pub_key_bio(bio) pubkey = EVP.PKey() pubkey.assign_rsa(rsa) # if you need a different digest than … Read more
I’m using BouncyCastle 1.57 (bcprov-jdk15on, bcmail-jdk15on and bcpkix-jdk15on) and Java 7. You can read the private key using the JcaPEMKeyConverter class. The code below works for keys with and without a password: import org.bouncycastle.jce.provider.BouncyCastleProvider; import org.bouncycastle.openssl.PEMDecryptorProvider; import org.bouncycastle.openssl.PEMEncryptedKeyPair; import org.bouncycastle.openssl.PEMKeyPair; import org.bouncycastle.openssl.PEMParser; import org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter; import org.bouncycastle.openssl.jcajce.JcePEMDecryptorProviderBuilder; // don’t forget to add the provider Security.addProvider(new BouncyCastleProvider()); … Read more
Code for the above answer public static PublicKey getKey(String key){ try{ byte[] byteKey = Base64.decode(key.getBytes(), Base64.DEFAULT); X509EncodedKeySpec X509publicKey = new X509EncodedKeySpec(byteKey); KeyFactory kf = KeyFactory.getInstance(“RSA”); return kf.generatePublic(X509publicKey); } catch(Exception e){ e.printStackTrace(); } return null; }
I’ve used something similar for my login page; it encrypts login credentials using the given public key information (N, e) which can be decrypted in PHP. It uses the following files that are part of JSBN: jsbn.js – to work with big integers rsa.js – for RSA encryption only (uses jsbn.js) rng.js – basic entropy … Read more
It depends on the tools you can use. I doubt there is a JavaScript too that could do it directly within the browser. It also depends if it’s a one-off (always the same key) or whether you need to script it. Command-line / OpenSSL If you want to use something like OpenSSL on a unix … Read more
When you use a code like this: using (var rsa = new RSACryptoServiceProvider(1024)) { // Do something with the key… // Encrypt, export, etc. } .NET (actually Windows) stores your key in a persistent key container forever. The container is randomly generated by .NET This means: Any random RSA/DSA key you have EVER generated for … Read more
Technically, yes. Depending on what kind of key you have the answer gets more tricky. Edit (2019-Oct): .NET Core 3.0 has built-in support for all of these formats, in their DER-encoded (vs PEM-encoded) forms. I’m adding the .NET Core 3.0+ answers after a sub-heading within each file format. PKCS#8 PrivateKeyInfo (PEM “BEGIN PRIVATE KEY”) If … Read more
RSA encryption is only mean for small amounts of data, the amount of data you can encrypt is dependent on the size of the key you are using, for example for 1024 bit RSA keys, and PKCS # 1 V1.5 padding, you can encrypt 117 bytes at most, with a 2048 RSA key, you can … Read more