Example usage for org.bouncycastle.openpgp PGPSignatureSubpacketGenerator setPreferredCompressionAlgorithms

Introduction

In this page you can find the example usage for org.bouncycastle.openpgp PGPSignatureSubpacketGenerator setPreferredCompressionAlgorithms.

Prototype

public void setPreferredCompressionAlgorithms(boolean isCritical, int[] algorithms) 

Source Link

Usage

From source file:org.sufficientlysecure.keychain.pgp.PgpKeyOperation.java

License:Open Source License

private static PGPSignatureSubpacketGenerator generateHashedSelfSigSubpackets(Date creationTime,
        PGPPublicKey pKey, boolean primary, int flags, long expiry) {

    PGPSignatureSubpacketGenerator hashedPacketsGen = new PGPSignatureSubpacketGenerator();
    {/* w ww.  j ava2  s  .  c  o  m*/
        /*
         * From RFC about critical subpackets:
         * If a subpacket is encountered that is
         * marked critical but is unknown to the evaluating software, the
         * evaluator SHOULD consider the signature to be in error.
         * An evaluator may "recognize" a subpacket, but not implement it.  The
         * purpose of the critical bit is to allow the signer to tell an
         * evaluator that it would prefer a new, unknown feature to generate an
         * error than be ignored.
         */
        /* non-critical subpackets: */
        hashedPacketsGen.setPreferredSymmetricAlgorithms(false,
                PgpSecurityConstants.PREFERRED_SYMMETRIC_ALGORITHMS);
        hashedPacketsGen.setPreferredHashAlgorithms(false, PgpSecurityConstants.PREFERRED_HASH_ALGORITHMS);
        hashedPacketsGen.setPreferredCompressionAlgorithms(false,
                PgpSecurityConstants.PREFERRED_COMPRESSION_ALGORITHMS);
        hashedPacketsGen.setPrimaryUserID(false, primary);

        /* critical subpackets: we consider those important for a modern pgp implementation */
        hashedPacketsGen.setSignatureCreationTime(true, creationTime);
        // Request that senders add the MDC to the message (authenticate unsigned messages)
        hashedPacketsGen.setFeature(true, Features.FEATURE_MODIFICATION_DETECTION);
        hashedPacketsGen.setKeyFlags(true, flags);
        if (expiry > 0) {
            hashedPacketsGen.setKeyExpirationTime(true, expiry - pKey.getCreationTime().getTime() / 1000);
        }
    }

    return hashedPacketsGen;
}

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