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package org.sufficientlysecure.keychain.pgp;
import org.spongycastle.bcpg.CompressionAlgorithmTags;
import org.spongycastle.bcpg.HashAlgorithmTags;
import org.spongycastle.bcpg.SymmetricKeyAlgorithmTags;
public class PgpConstants {
public static interface OpenKeychainSymmetricKeyAlgorithmTags extends SymmetricKeyAlgorithmTags {
public static final int USE_PREFERRED = -1;
}
public static interface OpenKeychainHashAlgorithmTags extends HashAlgorithmTags {
public static final int USE_PREFERRED = -1;
}
public static interface OpenKeychainCompressionAlgorithmTags extends CompressionAlgorithmTags {
public static final int USE_PREFERRED = -1;
}
// most preferred is first
public static final int[] PREFERRED_SYMMETRIC_ALGORITHMS = new int[]{
SymmetricKeyAlgorithmTags.AES_256,
SymmetricKeyAlgorithmTags.AES_192,
SymmetricKeyAlgorithmTags.AES_128,
SymmetricKeyAlgorithmTags.TWOFISH
};
public static final int[] PREFERRED_HASH_ALGORITHMS = new int[]{
HashAlgorithmTags.SHA256,
HashAlgorithmTags.SHA512,
HashAlgorithmTags.SHA384,
HashAlgorithmTags.SHA224,
HashAlgorithmTags.RIPEMD160
};
public static final int[] PREFERRED_COMPRESSION_ALGORITHMS = new int[]{
CompressionAlgorithmTags.ZLIB,
CompressionAlgorithmTags.BZIP2,
CompressionAlgorithmTags.ZIP
};
/*
* Note: s2kcount is a number between 0 and 0xff that controls the
* number of times to iterate the password hash before use. More
* iterations are useful against offline attacks, as it takes more
* time to check each password. The actual number of iterations is
* rather complex, and also depends on the hash function in use.
* Refer to Section 3.7.1.3 in rfc4880.txt. Bigger numbers give
* you more iterations. As a rough rule of thumb, when using
* SHA256 as the hashing function, 0x10 gives you about 64
* iterations, 0x20 about 128, 0x30 about 256 and so on till 0xf0,
* or about 1 million iterations. The maximum you can go to is
* 0xff, or about 2 million iterations.
* from http://kbsriram.com/2013/01/generating-rsa-keys-with-bouncycastle.html
*
* Bouncy Castle default: 0x60
* kbsriram proposes 0xc0
* we use 0x90, a good trade-off between usability and security against offline attacks
*/
public static final int SECRET_KEY_ENCRYPTOR_S2K_COUNT = 0x90;
public static final int SECRET_KEY_ENCRYPTOR_HASH_ALGO = HashAlgorithmTags.SHA256;
public static final int SECRET_KEY_ENCRYPTOR_SYMMETRIC_ALGO = SymmetricKeyAlgorithmTags.AES_256;
public static final int SECRET_KEY_SIGNATURE_HASH_ALGO = HashAlgorithmTags.SHA256;
// NOTE: only SHA1 is supported for key checksum calculations.
public static final int SECRET_KEY_SIGNATURE_CHECKSUM_HASH_ALGO = HashAlgorithmTags.SHA1;
}
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