}
protected PGPPrivateKey extractPrivateKey( PGPSecretKey secretKey, String privateKeyPassphrase ) {
BcPBESecretKeyDecryptorBuilder secretKeyDecryptorBuilder = new BcPBESecretKeyDecryptorBuilder( new BcPGPDigestCalculatorProvider() );
try {
PBESecretKeyDecryptor secretKeyDecryptor = secretKeyDecryptorBuilder.build( privateKeyPassphrase.toCharArray() );
return secretKey.extractPrivateKey( secretKeyDecryptor );
} catch ( Exception e ) {
throw new IllegalArgumentException( "Could not extract private key from key ring", e );
}
}