Subject: Re: Libssh2: Libgcrypt authentication failure

Re: Libssh2: Libgcrypt authentication failure

From: Simon Josefsson <>
Date: Sun, 22 Aug 2010 19:14:48 +0200

Alexander Lamaison <> writes:

> On 22 August 2010 08:58, Paul Romero <> wrote:
>> I am experiencing a problem with libssh2 version 1.2.6 which
>> I don't understand. The symptoms are described below and suggest
>> the problem is specific to libgcrypt. Any insight about the
>> problem would be greatly appreciated
> ...
>>    const char *username="paulr"; /* System Must stripped */
>>    const char *password="secret_agent";
>>    const char *loclfile="sftp_write_nonblock.c";
> ...
>> while ((rc = libssh2_userauth_publickey_fromfile(session, username,
>>        "/home/paulr/.ssh/",
>>        "/home/paulr/.ssh/id_rsa",
>>        password)) == LIBSSH2_ERROR_EAGAIN);
> I vaguely remember someone saying that libgcrypt can't handle a
> private key with a passphrase. Is this true or am I making things up?

It is true. The Libgcrypt backend in libssh2 contains a hand written
slimmed down ASN.1 parser to read out the RSA key, but it does not
support any of the PKCS* encrypted forms of RSA keys. The OpenSSL
backend in libssh2 uses OpenSSL to read the keys, so it supports
whatever private key formats that OpenSSL supports.

Received on 2010-08-22