Example usage for org.bouncycastle.crypto.modes CCMBlockCipher getOutputSize

Introduction

In this page you can find the example usage for org.bouncycastle.crypto.modes CCMBlockCipher getOutputSize.

Prototype

public int getOutputSize(int len) 

Source Link

Usage

From source file:COSE.EncryptCommon.java

private void AES_CCM_Decrypt(AlgorithmID alg, byte[] rgbKey)
        throws CoseException, IllegalStateException, InvalidCipherTextException {
    CCMBlockCipher cipher = new CCMBlockCipher(new AESFastEngine());
    KeyParameter ContentKey;//from  ww w  .j a va2s.co  m
    int cbIV = 0;

    switch (alg) {
    case AES_CCM_16_64_128:
    case AES_CCM_16_64_256:
    case AES_CCM_16_128_128:
    case AES_CCM_16_128_256:
        cbIV = 15 - 2;
        break;

    case AES_CCM_64_64_128:
    case AES_CCM_64_64_256:
    case AES_CCM_64_128_256:
    case AES_CCM_64_128_128:
        cbIV = 15 - 8;
        break;
    }

    //  The requirements from JWA

    CBORObject cn = FindAttribute(HeaderKeys.IV);
    if (cn == null)
        throw new CoseException("Missing IV during decryption");
    if (cn.getType() != CBORType.ByteString)
        throw new CoseException("IV is incorrectly formed");
    if (cn.GetByteString().length != cbIV)
        throw new CoseException("IV size is incorrect");

    byte[] IV = cn.GetByteString();

    if (rgbKey.length != alg.getKeySize() / 8)
        throw new CoseException("Missing IV during decryption");
    ContentKey = new KeyParameter(rgbKey);

    //  Build the object to be hashed

    AEADParameters parameters = new AEADParameters(ContentKey, alg.getTagSize(), IV, getAADBytes());

    cipher.init(false, parameters);
    byte[] C = new byte[cipher.getOutputSize(rgbEncrypt.length)];
    int len = cipher.processBytes(rgbEncrypt, 0, rgbEncrypt.length, C, 0);
    len += cipher.doFinal(C, len);

    rgbContent = C;
}

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From source file:COSE.EncryptCommon.java

private byte[] AES_CCM_Encrypt(AlgorithmID alg, byte[] rgbKey)
        throws CoseException, IllegalStateException, InvalidCipherTextException {
    CCMBlockCipher cipher = new CCMBlockCipher(new AESFastEngine());
    KeyParameter ContentKey;/*from w  ww .  j  a v  a  2 s.  c  o  m*/
    int cbIV;

    switch (alg) {
    case AES_CCM_16_64_128:
    case AES_CCM_16_64_256:
    case AES_CCM_16_128_128:
    case AES_CCM_16_128_256:
        cbIV = 15 - 2;
        break;

    case AES_CCM_64_64_128:
    case AES_CCM_64_64_256:
    case AES_CCM_64_128_256:
    case AES_CCM_64_128_128:
        cbIV = 15 - 8;
        break;

    default:
        throw new CoseException("Unsupported algorithm: " + alg);
    }

    //  The requirements from JWA

    byte[] IV = new byte[cbIV];
    CBORObject cbor = FindAttribute(HeaderKeys.IV);
    if (cbor != null) {
        if (cbor.getType() != CBORType.ByteString)
            throw new CoseException("IV is incorreclty formed.");
        if (cbor.GetByteString().length > cbIV)
            throw new CoseException("IV is too long.");
        IV = cbor.GetByteString();
    } else {
        random.nextBytes(IV);
        AddUnprotected(HeaderKeys.IV, CBORObject.FromObject(IV));
    }

    if (rgbKey.length != alg.getKeySize() / 8)
        throw new CoseException("Key Size is incorrect");
    ContentKey = new KeyParameter(rgbKey);

    //  Build the object to be hashed

    AEADParameters parameters = new AEADParameters(ContentKey, alg.getTagSize(), IV, getAADBytes());

    cipher.init(true, parameters);

    byte[] C = new byte[cipher.getOutputSize(rgbContent.length)];
    int len = cipher.processBytes(rgbContent, 0, rgbContent.length, C, 0);
    len += cipher.doFinal(C, len);

    return C;
}

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