# PK_Decryptor Class Reference

`#include <cryptlib.h>`

Inheritance diagram for PK_Decryptor:

List of all members.

## Detailed Description

interface for public-key decryptors

Definition at line 1265 of file cryptlib.h.

## Public Member Functions
virtual DecodingResult | Decrypt (RandomNumberGenerator &rng, const byte *ciphertext, size_t ciphertextLength, byte *plaintext, const NameValuePairs &parameters=g_nullNameValuePairs) const =0
| decrypt a byte string, and return the length of plaintext
virtual BufferedTransformation * | CreateDecryptionFilter (RandomNumberGenerator &rng, BufferedTransformation *attachment=NULL, const NameValuePairs &parameters=g_nullNameValuePairs) const
| create a new decryption filter
DecodingResult | FixedLengthDecrypt (RandomNumberGenerator &rng, const byte *ciphertext, byte *plaintext, const NameValuePairs &parameters=g_nullNameValuePairs) const
| decrypt a fixed size ciphertext
virtual size_t | MaxPlaintextLength (size_t ciphertextLength) const =0
| maximum length of plaintext for a given ciphertext length
virtual size_t | CiphertextLength (size_t plaintextLength) const =0
| calculate length of ciphertext given length of plaintext
virtual bool | ParameterSupported (const char *name) const =0
| this object supports the use of the parameter with the given name
virtual size_t | FixedCiphertextLength () const
| return fixed ciphertext length, if one exists, otherwise return 0
virtual size_t | FixedMaxPlaintextLength () const
| return maximum plaintext length given the fixed ciphertext length, if one exists, otherwise return 0
CryptoMaterial & | AccessMaterial ()
| returns a reference to the crypto material used by this object
const CryptoMaterial & | GetMaterial () const
| returns a const reference to the crypto material used by this object
virtual PrivateKey & | AccessPrivateKey ()=0
virtual const PrivateKey & | GetPrivateKey () const
void | BERDecode (BufferedTransformation &bt)
| for backwards compatibility, calls AccessMaterial().Load(bt)
void | DEREncode (BufferedTransformation &bt) const
| for backwards compatibility, calls GetMaterial().Save(bt)
virtual std::string | AlgorithmName () const
| returns name of this algorithm, not universally implemented yet
virtual Clonable * | Clone () const
| this is not implemented by most classes yet

## Member Function Documentation

virtual DecodingResult PK_Decryptor::Decrypt | ( | RandomNumberGenerator & | rng,
|  | const byte * | ciphertext,
|  | size_t | ciphertextLength,
|  | byte * | plaintext,
|  | const NameValuePairs & | parameters = `g_nullNameValuePairs` |
| ) |  |  | const`[pure virtual]`

decrypt a byte string, and return the length of plaintext

Precondition:
  size of plaintext == MaxPlaintextLength(ciphertextLength) bytes.

Returns:
  the actual length of the plaintext, indication that decryption failed.

Implemented in TF_DecryptorBase, DL_DecryptorBase< T >, and DL_DecryptorBase< SCHEME_OPTIONS::Element >.

BufferedTransformation * PK_Decryptor::CreateDecryptionFilter | ( | RandomNumberGenerator & | rng,
|  | BufferedTransformation * | attachment = `NULL`,
|  | const NameValuePairs & | parameters = `g_nullNameValuePairs` |
| ) |  |  | const`[virtual]`

create a new decryption filter

Note:
  caller is responsible for deleting the returned pointer

Definition at line 744 of file cryptlib.cpp.

virtual size_t PK_CryptoSystem::MaxPlaintextLength | ( | size_t | ciphertextLength | ) | const`[pure virtual, inherited]`

maximum length of plaintext for a given ciphertext length

Note:
  This function returns 0 if ciphertextLength is not valid (too long or too short).

virtual size_t PK_CryptoSystem::CiphertextLength | ( | size_t | plaintextLength | ) | const`[pure virtual, inherited]`

calculate length of ciphertext given length of plaintext

Note:
  This function returns 0 if plaintextLength is not valid (too long).

virtual bool PK_CryptoSystem::ParameterSupported | ( | const char * | name | ) | const`[pure virtual, inherited]`

this object supports the use of the parameter with the given name

some possible parameter names: EncodingParameters, KeyDerivationParameters

virtual size_t PK_CryptoSystem::FixedCiphertextLength | ( |  | ) | const`[inline, virtual, inherited]`

return fixed ciphertext length, if one exists, otherwise return 0

Note:
  "Fixed" here means length of ciphertext does not depend on length of plaintext. It usually does depend on the key length.

Definition at line 1225 of file cryptlib.h.

Referenced by FixedLengthDecrypt().

The documentation for this class was generated from the following files:

- cryptlib.h
- cryptlib.cpp