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provider-corner / vigenere

A toy provider implementing an expanded vigenere cipher, to serve as a programming example
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Question #8

Closed seschu closed 4 months ago

seschu commented 9 months ago

What is the purpose of ctx->ongoing ? It is used here

if (ctx->ongoing) {
    ERR_raise(ERR_HANDLE(ctx), VIGENERE_ONGOING_OPERATION);
    return 0;
}

Why would some one call set_ctx_params while using the algorithm? Is this to make it thread safe?

levitte commented 9 months ago

set_ctx_params is accessible to anyone through EVP_CIPHER_CTX_set_params(), so an application might very well call that at the wrong moment. So this is to prevent screwing up the encryption because some application author made a silly mistake.