class Poco::DigestEngine

Overview

This class is an abstract base class for all classes implementing a message digest algorithm, like MD5Engine and SHA1Engine. More…

#include <DigestEngine.h>

class DigestEngine
{
public:
    // typedefs

    typedef std::vector<unsigned char> Digest;

    // methods

    void
    update(
        const void* data,
        std::size_t length
        );

    void
    update(char data);

    void
    update(const std::string& data);

    virtual
    std::size_t
    digestLength() const = 0;

    virtual
    void
    reset() = 0;

    virtual
    const Digest&
    digest() = 0;

    static
    std::string
    digestToHex(const Digest& bytes);

    static
    Digest
    digestFromHex(const std::string& digest);

protected:
    // methods

    virtual
    void
    updateImpl(
        const void* data,
        std::size_t length
        ) = 0;
};

// direct descendants

template <class Engine>
class HMACEngine;

class MD4Engine;
class MD5Engine;

template <class PRF>
class PBKDF2Engine;

class SHA1Engine;

Detailed Documentation

This class is an abstract base class for all classes implementing a message digest algorithm, like MD5Engine and SHA1Engine.

Call update() repeatedly with data to compute the digest from. When done, call digest() to obtain the message digest.

Methods

void
update(const std::string& data)

Updates the digest with the given data.

virtual
std::size_t
digestLength() const = 0

Returns the length of the digest in bytes.

virtual
void
reset() = 0

Resets the engine so that a new digest can be computed.

virtual
const Digest&
digest() = 0

Finishes the computation of the digest and returns the message digest.

Resets the engine and can thus only be called once for every digest. The returned reference is valid until the next time digest() is called, or the engine object is destroyed.

static
std::string
digestToHex(const Digest& bytes)

Converts a message digest into a string of hexadecimal numbers.

static
Digest
digestFromHex(const std::string& digest)

Converts a string created by digestToHex back to its Digest presentation.

virtual
void
updateImpl(
    const void* data,
    std::size_t length
    ) = 0

Updates the digest with the given data.

Must be implemented by subclasses.