'\" t
.\"     Title: kcapi_kdf_dpi
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: November 2020
.\"    Manual: Programming Interface
.\"    Source: libkcapi Manual 1.2.1
.\"  Language: English
.\"
.TH "KCAPI_KDF_DPI" "3" "November 2020" "libkcapi Manual 1\&.2\&.1" "Programming Interface"
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.SH "NAME"
kcapi_kdf_dpi \- Double Pipeline Mode Key Derivation Function
.SH "SYNOPSIS"
.HP \w'int32_t\ kcapi_kdf_dpi('u
.BI "int32_t kcapi_kdf_dpi(struct\ kcapi_handle\ *\ " "handle" ", const\ uint8_t\ *\ " "src" ", uint32_t\ " "slen" ", uint8_t\ *\ " "dst" ", uint32_t\ " "dlen" ");"
.SH "ARGUMENTS"
.PP
\fIhandle\fR
.RS 4
[in] cipher handle allocated by caller\&. This cipher handle must be allocated with
\fBkcapi_md_init\fR\&. If the caller is interested in a KDF using a keyed message digest, the caller should also call
\fBkcapi_md_setkey\fR
before invoking this function\&.
.RE
.PP
\fIsrc\fR
.RS 4
[in] Input data that should be transformed into a key (see below)\&.
.RE
.PP
\fIslen\fR
.RS 4
[in] Length of the src input data\&.
.RE
.PP
\fIdst\fR
.RS 4
[out] Buffer to store the generated key in,
.RE
.PP
\fIdlen\fR
.RS 4
[in] Length of the dst buffer\&. This value defines the number of bytes generated by the KDF\&.
.RE
.SH "DESCRIPTION"
.PP
This function is an implementation of the KDF in double pipeline iteration mode according with counter to SP800\-108 section 5\&.3\&.
.PP
The caller must provide Label || 0x00 || Context in src\&. This src pointer may also be NULL if the caller wishes not to provide anything\&.
.PP
\fIreturn\fR
0 upon success; a negative errno\-style error code if an error occurred
.SH "AUTHOR"
.PP
\fBStephan Mueller\fR <\&smueller@chronox.de\&>
.RS 4
Author.
.RE
.SH "COPYRIGHT"
.br