fc::aes_decoder Class Reference

#include <aes.hpp>

Classes
struct	impl

Public Member Functions
void	init (const fc::sha256 &key, const fc::uint128 &init_value)
uint32_t	decode (const char *ciphertxt, uint32_t len, char *plaintext)

Detailed Description

Definition at line 22 of file aes.hpp.

Member Function Documentation

decode()

uint32_t fc::aes_decoder::decode	(	const char *	ciphertxt,
		uint32_t	len,
		char *	plaintext )

Definition at line 116 of file aes.cpp.

{
    int plaintext_len = 0;
    /* Provide the message to be decrypted, and obtain the decrypted output.
    *    * EVP_DecryptUpdate can be called multiple times if necessary
    *       */
    if (1 != EVP_DecryptUpdate(my->ctx, (unsigned char*)plaintext, &plaintext_len, (const unsigned char*)ciphertxt, ciphertxt_len))
    {
        FC_THROW_EXCEPTION( aes_exception, "error during aes 256 cbc decryption update", 
                           ("s", ERR_error_string( ERR_get_error(), nullptr) ) );
    }
    FC_ASSERT( ciphertxt_len == static_cast<unsigned>(plaintext_len), "", ("ciphertxt_len",ciphertxt_len)("plaintext_len",plaintext_len) );
    return plaintext_len;
}

init()

void fc::aes_decoder::init	(	const fc::sha256 &	key,
		const fc::uint128 &	init_value )

Definition at line 93 of file aes.cpp.

{
    my->ctx.obj = EVP_CIPHER_CTX_new();
    /* Create and initialise the context */
    if(!my->ctx)
    {
        FC_THROW_EXCEPTION( aes_exception, "error allocating evp cipher context", 
                           ("s", ERR_error_string( ERR_get_error(), nullptr) ) );
    }
 
    /* Initialise the encryption operation. IMPORTANT - ensure you use a key
    *    and IV size appropriate for your cipher
    *    In this example we are using 256 bit AES (i.e. a 256 bit key). The
    *    IV size for *most* modes is the same as the block size. For AES this
    *    is 128 bits */
    if(1 != EVP_DecryptInit_ex(my->ctx, EVP_aes_256_cbc(), NULL, (unsigned char*)&key, (unsigned char*)&init_value))
    {
        FC_THROW_EXCEPTION( aes_exception, "error during aes 256 cbc encryption init", 
                           ("s", ERR_error_string( ERR_get_error(), nullptr) ) );
    }
    EVP_CIPHER_CTX_set_padding( my->ctx, 0 );
}

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

• libraries/fc/include/fc/crypto/aes.hpp
• libraries/fc/src/crypto/aes.cpp