DES_READ_PW(3)

NAME
EVP_read_pw_string, EVP_read_pw_string_min, EVP_set_pw_prompt, EVP_get_pw_prompt - compatibility user interface functions

SYNOPSIS
libcrypto
#include <openssl/evp.h>
int
EVP_read_pw_string(char *buf, int length, const char *prompt, int verify);
int
EVP_read_pw_string_min(char *buf, int min_length, int length, const char *prompt, int verify);
void
EVP_set_pw_prompt(const char *default_prompt);
char *
EVP_get_pw_prompt(void);

DESCRIPTION
EVP_read_pw_string() writes the prompt to /dev/tty, or, if that could not be opened, to standard output, turns echo off, and reads an input string from /dev/tty, or, if that could not be opened, from standard input. The string is returned in buf, which must have space for at least length bytes. If the length argument exceeds BUFSIZ, BUFSIZ is used instead. If verify is set, the user is asked for the password twice and unless the two copies match, an error is returned.

EVP_read_pw_string_min() additionally checks that the password is at least min_length bytes long.

EVP_set_pw_prompt() sets a default prompt to a copy of default_prompt, or clears the default prompt if the default_prompt argument is NULL or an empty string. If the default_prompt argument is longer than 79 bytes, the copy is silently truncated to a string length of 79 bytes.

As long as a default prompt is set, EVP_read_pw_string() and EVP_read_pw_string_min() can be called with a prompt argument of NULL, in which case the default prompt is used instead.

RETURN VALUES
EVP_read_pw_string() and EVP_read_pw_string_min() return 0 on success or a negative value on failure.

They return -1 if length is less than or equal to zero or on memory allocation failure. They return -1 or -2 if the internal call to UI_process(3) fails.

In addition, EVP_read_pw_string_min returns -1 if min_length is negative, if length is less than or equal to min_length, or if the user entered a password shorter than min_length.

EVP_get_pw_prompt() returns an internal pointer to static memory containing the default prompt, or NULL if no default prompt is set.

SEE ALSO
UI_new(3)

HISTORY
EVP_read_pw_string() first appeared in SSLeay 0.5.1 and EVP_set_pw_prompt() and EVP_get_pw_prompt() in SSLeay 0.6.0. These functions have been available since OpenBSD 2.4.

EVP_read_pw_string_min() first appeared in OpenSSL 1.0.0 and has been available since OpenBSD 4.9.