libssh2\_agent\_sign(3) libssh2 libssh2\_agent\_sign(3) # [NAME](#NAME) libssh2\_agent\_sign - sign data, with the help of ssh-agent # [SYNOPSIS](#SYNOPSIS) ``` #include int libssh2_agent_sign(LIBSSH2_AGENT *agent, struct libssh2_agent_publickey *identity, unsigned char **sig, size_t *s_len, const unsigned char *data, size_t d_len, const char *method, unsigned int method_len); ``` # [DESCRIPTION](#DESCRIPTION) *agent* - ssh-agent handle as returned by [**libssh2\_agent\_init(3)**](/man/os/libssh2/libssh2_agent_init.3) *identity* - Public key to authenticate with, as returned by [**libssh2\_agent\_get\_identity(3)**](/man/os/libssh2/libssh2_agent_get_identity.3) *sig* - A pointer to a buffer in which to place the signature. The caller is responsible for freeing the signature with LIBSSH2\_FREE. *s\_len* - A pointer to the length of the sig parameter. *data* - The data to sign. *d\_len* - The length of the data parameter. *method* - A buffer indicating the signing method. This should match the string at the start of identity->blob. *method\_len* - The length of the method parameter. Sign data using an ssh-agent. This function can be used in a callback registered with [libssh2\_session\_callback\_set2(3)](/man/os/libssh2/libssh2_session_callback_set2.3) using LIBSSH2\_CALLBACK\_AUTHAGENT\_SIGN to sign an authentication challenge from a server. However, the client is responsible for implementing the code that calls this callback in response to a SSH2\_AGENTC\_SIGN\_REQUEST message. # [RETURN VALUE](#RETURN_VALUE) Returns 0 if succeeded, or a negative value for error. # [AVAILABILITY](#AVAILABILITY) Added in libssh2 1.11.0 # [SEE ALSO](#SEE_ALSO) [**libssh2\_agent\_init(3)**](/man/os/libssh2/libssh2_agent_init.3) [**libssh2\_agent\_get\_identity(3)**](/man/os/libssh2/libssh2_agent_get_identity.3) [**libssh2\_agent\_userauth(3)**](/man/os/libssh2/libssh2_agent_userauth.3) [**libssh2\_session\_callback\_set2(3)**](/man/os/libssh2/libssh2_session_callback_set2.3) 1 Oct 2022 libssh2 --- Document: libssh2_agent_sign(3) from libssh2 1.11.1-r11 (Chainguard OS) Source: https://github.com/libssh2/libssh2.git