org.bouncycastle.tls.crypto.impl.TlsImplUtils Maven / Gradle / Ivy

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The Bouncy Castle Java APIs for the TLS, including a JSSE provider. The APIs are designed primarily to be used in conjunction with the BC FIPS provider. The APIs may also be used with other providers although if being used in a FIPS context it is the responsibility of the user to ensure that any other providers used are FIPS certified and used appropriately.

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package org.bouncycastle.tls.crypto.impl;

import org.bouncycastle.tls.ExporterLabel;
import org.bouncycastle.tls.ProtocolVersion;
import org.bouncycastle.tls.SecurityParameters;
import org.bouncycastle.tls.crypto.TlsCryptoParameters;
import org.bouncycastle.tls.crypto.TlsSecret;
import org.bouncycastle.util.Arrays;

/**
 * Useful utility methods.
 */
public class TlsImplUtils
{
    public static boolean isTLSv11(ProtocolVersion version)
    {
        return ProtocolVersion.TLSv11.isEqualOrEarlierVersionOf(version.getEquivalentTLSVersion());
    }

    public static boolean isTLSv11(TlsCryptoParameters cryptoParams)
    {
        return isTLSv11(cryptoParams.getServerVersion());
    }

    public static boolean isTLSv12(ProtocolVersion version)
    {
        return ProtocolVersion.TLSv12.isEqualOrEarlierVersionOf(version.getEquivalentTLSVersion());
    }

    public static boolean isTLSv12(TlsCryptoParameters cryptoParams)
    {
        return isTLSv12(cryptoParams.getServerVersion());
    }

    public static byte[] calculateKeyBlock(TlsCryptoParameters cryptoParams, int length)
    {
        SecurityParameters securityParameters = cryptoParams.getSecurityParameters();
        TlsSecret master_secret = securityParameters.getMasterSecret();
        byte[] seed = Arrays.concatenate(securityParameters.getServerRandom(), securityParameters.getClientRandom());
        return PRF(cryptoParams, master_secret, ExporterLabel.key_expansion, seed, length).extract();
    }

    public static TlsSecret PRF(TlsCryptoParameters cryptoParams, TlsSecret secret, String asciiLabel, byte[] seed, int length)
    {
        int prfAlgorithm = cryptoParams.getSecurityParameters().getPrfAlgorithm();

        return secret.deriveUsingPRF(prfAlgorithm, asciiLabel, seed, length);
    }
}