1SSL_CTX_set_default_passwd_cb(3)    OpenSSL   SSL_CTX_set_default_passwd_cb(3)
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NAME

6       SSL_CTX_set_default_passwd_cb, SSL_CTX_set_default_passwd_cb_userdata -
7       set passwd callback for encrypted PEM file handling
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SYNOPSIS

10        #include <openssl/ssl.h>
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12        void SSL_CTX_set_default_passwd_cb(SSL_CTX *ctx, pem_password_cb *cb);
13        void SSL_CTX_set_default_passwd_cb_userdata(SSL_CTX *ctx, void *u);
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15        int pem_passwd_cb(char *buf, int size, int rwflag, void *userdata);
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DESCRIPTION

18       SSL_CTX_set_default_passwd_cb() sets the default password callback
19       called when loading/storing a PEM certificate with encryption.
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21       SSL_CTX_set_default_passwd_cb_userdata() sets a pointer to userdata
22       which will be provided to the password callback on invocation.
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24       The pem_passwd_cb(), which must be provided by the application, hands
25       back the password to be used during decryption. On invocation a pointer
26       to userdata is provided. The pem_passwd_cb must write the password into
27       the provided buffer buf which is of size size. The actual length of the
28       password must be returned to the calling function. rwflag indicates
29       whether the callback is used for reading/decryption (rwflag=0) or
30       writing/encryption (rwflag=1).
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NOTES

33       When loading or storing private keys, a password might be supplied to
34       protect the private key. The way this password can be supplied may
35       depend on the application. If only one private key is handled, it can
36       be practical to have pem_passwd_cb() handle the password dialog
37       interactively. If several keys have to be handled, it can be practical
38       to ask for the password once, then keep it in memory and use it several
39       times. In the last case, the password could be stored into the userdata
40       storage and the pem_passwd_cb() only returns the password already
41       stored.
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43       When asking for the password interactively, pem_passwd_cb() can use
44       rwflag to check, whether an item shall be encrypted (rwflag=1).  In
45       this case the password dialog may ask for the same password twice for
46       comparison in order to catch typos, that would make decryption
47       impossible.
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49       Other items in PEM formatting (certificates) can also be encrypted, it
50       is however not usual, as certificate information is considered public.
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RETURN VALUES

53       SSL_CTX_set_default_passwd_cb() and
54       SSL_CTX_set_default_passwd_cb_userdata() do not provide diagnostic
55       information.
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EXAMPLES

58       The following example returns the password provided as userdata to the
59       calling function. The password is considered to be a '\0' terminated
60       string. If the password does not fit into the buffer, the password is
61       truncated.
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63        int pem_passwd_cb(char *buf, int size, int rwflag, void *password)
64        {
65         strncpy(buf, (char *)(password), size);
66         buf[size - 1] = '\0';
67         return(strlen(buf));
68        }
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SEE ALSO

71       ssl(3), SSL_CTX_use_certificate(3)
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751.0.2o                            2020-01-28  SSL_CTX_set_default_passwd_cb(3)
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