method

auth_tag=

v2_1_10 - Show latest stable - Class: OpenSSL::Cipher

auth_tag=(p1)

public

Sets the authentication tag to verify the contents of the ciphertext. The tag must be set after calling Cipher#decrypt, Cipher#key= and Cipher#iv=, but before assigning the associated authenticated data using Cipher#auth_data= and of course, before decrypting any of the ciphertext. After all decryption is performed, the tag is verified automatically in the call to Cipher#final.

static VALUE
ossl_cipher_set_auth_tag(VALUE self, VALUE vtag)
{
    EVP_CIPHER_CTX *ctx;
    int nid;
    unsigned char *tag;
    int tag_len;

    StringValue(vtag);
    tag = (unsigned char *) RSTRING_PTR(vtag);
    tag_len = RSTRING_LENINT(vtag);

    GetCipher(self, ctx);
    nid = EVP_CIPHER_CTX_nid(ctx);

    if (ossl_is_gcm(nid)) {
        ossl_set_gcm_auth_tag(ctx, tag, tag_len);
    } else {
        ossl_raise(eCipherError, "authentication tag not supported by this cipher");
    }

    return vtag;
}

auth_tag=

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