/// <summary>
/// Decrypts the specified Base64 string ciphertext.
/// </summary>
/// <typeparam name="T">
/// The type of the object that is decrypted.
/// </typeparam>
/// <param name="target">
/// The current <see cref="ISymmetricProcessor{T}" />.
/// </param>
/// <param name="ciphertext">
/// The Base64 string ciphertext to decrypt.
/// </param>
/// <param name="key">
/// The key derivation bits used to transform the ciphertext.
/// </param>
/// <param name="algorithm">
/// The algorithm specification used to transform the ciphertext.
/// </param>
/// <returns>
/// The resulting plaintext object.
/// </returns>
/// <exception cref="FormatException">
/// <paramref name="ciphertext" /> is not a valid Base64 string.
/// </exception>
/// <exception cref="SecurityException">
/// An exception was raised during decryption or deserialization.
/// </exception>
public static T DecryptFromBase64String <T>(this ISymmetricProcessor <T> target, String ciphertext, SecureBuffer key, SymmetricAlgorithmSpecification algorithm) => target.Decrypt(Convert.FromBase64String(ciphertext), key, algorithm);
/// <summary>
/// Decrypts the specified Base64 string ciphertext.
/// </summary>
/// <typeparam name="T">
/// The type of the object that is decrypted.
/// </typeparam>
/// <param name="target">
/// The current <see cref="ISymmetricProcessor{T}" />.
/// </param>
/// <param name="ciphertext">
/// The Base64 string ciphertext to decrypt.
/// </param>
/// <param name="key">
/// The key derivation bits and algorithm specification used to transform the ciphertext.
/// </param>
/// <returns>
/// The resulting plaintext object.
/// </returns>
/// <exception cref="FormatException">
/// <paramref name="ciphertext" /> is not a valid Base64 string.
/// </exception>
/// <exception cref="SecurityException">
/// An exception was raised during decryption or deserialization.
/// </exception>
public static T DecryptFromBase64String <T>(this ISymmetricProcessor <T> target, String ciphertext, SecureSymmetricKey key) => target.Decrypt(Convert.FromBase64String(ciphertext), key);