craterdog.security

Interface MessageDecryption

All Known Implementing Classes:

MessageCryptex

public interface MessageDecryption

This interface defines the methods needed to do message level symmetric key decryption when the sender and receiver have already exchanged their asymmetric public keys.

Author:

Derk Norton

Method Summary

Modifier and Type	Method and Description
boolean	bytesAreValid(PublicKey certificate, byte[] bytes, byte[] signature) This method checks to see if the signature for a signed byte array is valid.
byte[]	decodeString(String base64String) This method decodes a base 64 string into its original bytes.
CipherInputStream	decryptionInputStream(SecretKey sharedKey, InputStream input) This method generates an input stream that performs decryption on another input stream.
SecretKey	decryptSharedKey(PrivateKey privateKey, byte[] encryptedKey) This method decrypts a shared key using the private key that is paired with the public certificate that was used to encrypt it at the source.
void	decryptStream(SecretKey sharedKey, InputStream input, OutputStream output) This method decrypts a byte stream from an encrypted byte stream.
String	decryptString(SecretKey sharedKey, byte[] encryptedString) This method decrypts a string using a shared key.

Method Detail

decodeString

byte[] decodeString(String base64String)

This method decodes a base 64 string into its original bytes.

Parameters:

base64String - The base 64 encoded string.

Returns:

The corresponding decoded bytes.

bytesAreValid

boolean bytesAreValid(PublicKey certificate,
                      byte[] bytes,
                      byte[] signature)

This method checks to see if the signature for a signed byte array is valid.

Parameters:

certificate - The certificate containing the matching public key for the private key that signed the bytes.

bytes - The byte array to be signed.

signature - The signature to be validated.

Returns:

Whether or not the signature matches the byte array.

decryptSharedKey

SecretKey decryptSharedKey(PrivateKey privateKey,
                           byte[] encryptedKey)

This method decrypts a shared key using the private key that is paired with the public certificate that was used to encrypt it at the source. The public certificate and private key belong to the destination of the communication.

Parameters:

privateKey - The private key of the destination.

encryptedKey - The encrypted shared key.

Returns:

The decrypted shared key.

decryptString

String decryptString(SecretKey sharedKey,
                     byte[] encryptedString)

This method decrypts a string using a shared key.

Parameters:

sharedKey - The shared key used for the encryption.

encryptedString - The encrypted string.

Returns:

The decrypted string.

decryptStream

void decryptStream(SecretKey sharedKey,
                   InputStream input,
                   OutputStream output)
            throws IOException

This method decrypts a byte stream from an encrypted byte stream.

Parameters:

sharedKey - The shared key used for the encryption.

input - The encrypted byte stream.

output - The decrypted byte stream.

Throws:

IOException - Unable to decrypt the stream.

decryptionInputStream

CipherInputStream decryptionInputStream(SecretKey sharedKey,
                                        InputStream input)
                                 throws IOException

This method generates an input stream that performs decryption on another input stream.

Parameters:

sharedKey - The shared key used for the encryption.

input - The input stream to be decrypted.

Returns:

The decrypting input stream.

Throws:

IOException - Unable to create a decryption input stream.