SSL_CTX_use_psk_identity_hint.3 revision 312826
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Title "SSL_CTX_use_psk_identity_hint 3"
SSL_CTX_use_psk_identity_hint 3 "2017-01-26" "1.0.2k" "OpenSSL"
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"NAME"
SSL_CTX_use_psk_identity_hint, SSL_use_psk_identity_hint, SSL_CTX_set_psk_server_callback, SSL_set_psk_server_callback - set PSK identity hint to use
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #include <openssl/ssl.h> \& int SSL_CTX_use_psk_identity_hint(SSL_CTX *ctx, const char *hint); int SSL_use_psk_identity_hint(SSL *ssl, const char *hint); \& void SSL_CTX_set_psk_server_callback(SSL_CTX *ctx, unsigned int (*callback)(SSL *ssl, const char *identity, unsigned char *psk, int max_psk_len)); void SSL_set_psk_server_callback(SSL *ssl, unsigned int (*callback)(SSL *ssl, const char *identity, unsigned char *psk, int max_psk_len)); .Ve
"DESCRIPTION"
Header "DESCRIPTION" \fISSL_CTX_use_psk_identity_hint() sets the given \s-1NULL\s0-terminated \s-1PSK\s0 identity hint hint to \s-1SSL\s0 context object \fBctx. SSL_use_psk_identity_hint() sets the given \s-1NULL\s0-terminated \s-1PSK\s0 identity hint hint to \s-1SSL\s0 connection object ssl. If hint is \s-1NULL\s0 the current hint from ctx or ssl is deleted.

In the case where \s-1PSK\s0 identity hint is \s-1NULL\s0, the server does not send the ServerKeyExchange message to the client.

A server application must provide a callback function which is called when the server receives the ClientKeyExchange message from the client. The purpose of the callback function is to validate the received \s-1PSK\s0 identity and to fetch the pre-shared key used during the connection setup phase. The callback is set using functions \fISSL_CTX_set_psk_server_callback() or \fISSL_set_psk_server_callback(). The callback function is given the connection in parameter ssl, \s-1NULL\s0-terminated \s-1PSK\s0 identity sent by the client in parameter identity, and a buffer psk of length \fBmax_psk_len bytes where the pre-shared key is to be stored.

"RETURN VALUES"
Header "RETURN VALUES" \fISSL_CTX_use_psk_identity_hint() and SSL_use_psk_identity_hint() return 1 on success, 0 otherwise.

Return values from the server callback are interpreted as follows:

"0" 4
\s-1PSK\s0 identity was not found. An \*(L"unknown_psk_identity\*(R" alert message will be sent and the connection setup fails.
">0" 4
Item ">0" \s-1PSK\s0 identity was found and the server callback has provided the \s-1PSK\s0 successfully in parameter psk. Return value is the length of \fBpsk in bytes. It is an error to return a value greater than \fBmax_psk_len. .Sp If the \s-1PSK\s0 identity was not found but the callback instructs the protocol to continue anyway, the callback must provide some random data to psk and return the length of the random data, so the connection will fail with decryption_error before it will be finished completely.