Poco::Crypto

class RSADigestEngine

Library: Crypto
Package: RSA
Header: Poco/Crypto/RSADigestEngine.h

Description

This class implements a Poco::DigestEngine that can be used to compute a secure digital signature.

First another Poco::Crypto::DigestEngine is created and used to compute a cryptographic hash of the data to be signed. Then, the hash value is encrypted, using the RSA private key.

To verify a signature, pass it to the verify() member function. It will decrypt the signature using the RSA public key and compare the resulting hash with the actual hash of the data.

Inheritance

Direct Base Classes: Poco::DigestEngine

All Base Classes: Poco::DigestEngine

Member Summary

Member Functions: digest, digestLength, reset, signature, updateImpl, verify

Inherited Functions: digest, digestFromHex, digestLength, digestToHex, reset, update, updateImpl

Enumerations

DigestType

DIGEST_MD5

DIGEST_SHA1

Constructors

RSADigestEngine

RSADigestEngine(
    const RSAKey & key,
    DigestType digestType = DIGEST_SHA1
);

Deprecated. This function is deprecated and should no longer be used.

Creates the RSADigestEngine with the given RSA key, using the MD5 or SHA-1 hash algorithm. Kept for backward compatibility

RSADigestEngine

RSADigestEngine(
    const RSAKey & key,
    const std::string & name
);

Creates the RSADigestEngine with the given RSA key, using the hash algorithm with the given name (e.g., "MD5", "SHA1", "SHA256", "SHA512", etc.). See the OpenSSL documentation for a list of supported digest algorithms.

Throws a Poco::NotFoundException if no algorithm with the given name exists.

Destructor

~RSADigestEngine virtual

~RSADigestEngine();

Destroys the RSADigestEngine.

Member Functions

digest

const DigestEngine::Digest & digest();

Finishes the computation of the digest (the first time it's called) and returns the message digest.

Can be called multiple times.

digestLength virtual

std::size_t digestLength() const;

Returns the length of the digest in bytes.

reset virtual

void reset();

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

signature

const DigestEngine::Digest & signature();

Signs the digest using the RSA algorithm and the private key (teh first time it's called) and returns the result.

Can be called multiple times.

verify

bool verify(
    const DigestEngine::Digest & signature
);

Verifies the data against the signature.

Returns true if the signature can be verified, false otherwise.

updateImpl protected virtual

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