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: constantTimeEquals, digest, digestFromHex, digestLength, digestToHex, reset, update, updateImpl
Enumerations
DigestType
Constructors
RSADigestEngine
RSADigestEngine(
const RSAKey & key,
DigestType digestType = DIGEST_SHA1
);
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 
~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
std::size_t digestLength() const;
Returns the length of the digest in bytes.
See also: Poco::DigestEngine::digestLength()
reset
void reset();
Resets the engine so that a new digest can be computed.
See also: Poco::DigestEngine::reset()
signature
const DigestEngine::Digest & signature();
Signs the digest using the RSA algorithm and the private key (the 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 
void updateImpl(
const void * data,
std::size_t length
);
See also: Poco::DigestEngine::updateImpl()