Reading an elliptic curve private key from a file using BouncyCastle

Question

BouncyCastle cryptography APIs allow you to create and verify digital signatures using common package objects java.security, such as java.security.PublicKey, java.security.PrivateKeyand their container java.security.KeyPair.

Suppose I use OpenSSL to create a .pem file (or, if simpler .der) containing the private key of an elliptic curve that I want to use in my application. For example, it looks like this:

-----BEGIN EC PARAMETERS-----
BgUrgQQACg==
-----END EC PARAMETERS-----
-----BEGIN EC PRIVATE KEY-----
MHQCAQEEIDzESrZFmTaOozu2NyiS8LMZGqkHfpSOoI/qA9Lw+d4NoAcGBSuBBAAK
oUQDQgAE7kIqoSQzC/UUXdFdQ9Xvu1Lri7pFfd7xDbQWhSqHaDtj+XY36Z1Cznun
GDxlA0AavdVDuoGXxNQPIed3FxPE3Q==
-----END EC PRIVATE KEY-----

How to use the BouncyCastle API to receive java.security.KeyPair, containing both this private key and the corresponding public key?

, API, BouncyCastle 1.50 ( ), API. , PEMReader, SO. , ; RSA DSA.

Answer 1

Java . , , Base64 :

public static PrivateKey keyToValue(byte[] pkcs8key)
    throw GeneralSecurityException {

    PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(pkcs8key);
    KeyFactory factory = KeyFactory.getInstance("ECDSA");
    PrivateKey privateKey = factory.generatePrivate(spec);
    return privateKey;
}

Answer 2

JCE divanov, (. ) JCE , selfanswer, BouncyCastle 1.48 up. PEMReader, -, - :

static void SO22963581BCPEMPrivateEC () throws Exception {
    Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
    Reader rdr = new StringReader ("-----BEGIN EC PRIVATE KEY-----\n"
            +"MHQCAQEEIDzESrZFmTaOozu2NyiS8LMZGqkHfpSOoI/qA9Lw+d4NoAcGBSuBBAAK\n"
            +"oUQDQgAE7kIqoSQzC/UUXdFdQ9Xvu1Lri7pFfd7xDbQWhSqHaDtj+XY36Z1Cznun\n"
            +"GDxlA0AavdVDuoGXxNQPIed3FxPE3Q==\n"+"-----END EC PRIVATE KEY-----\n");
    Object parsed = new org.bouncycastle.openssl.PEMParser(rdr).readObject();
    KeyPair pair = new org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter().getKeyPair((org.bouncycastle.openssl.PEMKeyPair)parsed);
    System.out.println (pair.getPrivate().getAlgorithm());
}

Answer 3

, ( Scala). -, REPL :

Security.addProvider(new BouncyCastleProvider)

val SignatureScheme = "some signature scheme, eg ECDSA"
val RandomAlgorithm = "some random algorithm, eg SHA1PRNG"

val keygen = KeyPairGenerator.getInstance(SignatureScheme)
val rng = SecureRandom.getInstance(RandomAlgorithm)
rng.setSeed(seed)
keygen.initialize(KeySize, rng)

val kp = keygen.generateKeyPair()
println(kp.getPublic.getEncoded.toSeq) // toSeq so that Scala actually prints it
println(kp.getPrivate.getEncoded.toSeq)

, ,

val hardcodedPublic = Array[Byte]( /* data */ )
val hardcodedPrivate = Array[Byte]( /* data */ )

val factory = KeyFactory.getInstance(SignatureScheme)

val publicSpec = new X509EncodedKeySpec(hardcodedPublic)
val publicKey = factory.generatePublic(publicSpec)

val privateSpec = new PKCS8EncodedKeySpec(hardcodedPrivate)
val privateKey = factory.generatePrivate(privateSpec)

, , , X509, PKCS8. , OpenSSL , , .

SpongyCastle ( Android BouncyCastle) . , , BouncyCastle .

Update : The BouncyCastle wiki is included, and you can find the documentation here .