These classes are not directly related to the crypt functionality, but most were necessary for its implementation, so I see no reason not to make them available. You may find them useful for other purposes.
Classes
Class  Description  

Base16Encoding 
Base16 binarytotext encodings.
 
Base2Encoding 
Base2 binarytotext encodings.
 
Base32Encoding 
Base32 binary to text encodings.
I needed multiple variations of base64 for the various crypt algorithms, and base16 (hex) for test vectors,
so base32 is mostly a freebie. It's great for email verifications, product keys  really anywhere you need
someone to type in a randomlygenerated code.
 
Base64Encoding 
Base64 binarytotext encodings.
 
BaseEncoding 
Performs generic binarytotext encoding.
 
BlowfishCipher 
Performs lowlevel encryption and decryption using the Blowfish cipher.
 
DesCipher 
Performs lowlevel encryption and decryption using the DES cipher.
 
Pbkdf2 
Implements the PBKDF2 key derivation function.
 
Salsa20Core 
Implements the Salsa20 hash function.
 
SCrypt 
Implements the SCrypt key derivation function.
 
SecureComparison 
Provides comparison methods resistant to timing attack.

Delegates
Delegate  Description  

BaseEncodingDecodeFilterCallback 
A callback to map arbitrary characters onto the characters that can be decoded.

Enumerations
Enumeration  Description  

EksBlowfishKeyExpansionFlags 
Modifiers for Expensive Key Schedule (EKS) Blowfish key expansion behavior.
