PNG  IHDRQgAMA a cHRMz&u0`:pQ<bKGDgmIDATxwUﹻ& ^CX(J I@ "% (** BX +*i"]j(IH{~R)[~>h{}gy)I$Ij .I$I$ʊy@}x.: $I$Ii}VZPC)I$IF ^0ʐJ$I$Q^}{"r=OzI$gRZeC.IOvH eKX $IMpxsk.쒷/&r[޳<v| .I~)@$updYRa$I |M.e JaֶpSYR6j>h%IRز if&uJ)M$I vLi=H;7UJ,],X$I1AҒJ$ XY XzI@GNҥRT)E@;]K*Mw;#5_wOn~\ DC&$(A5 RRFkvIR}l!RytRl;~^ǷJj اy뷦BZJr&ӥ8Pjw~vnv X^(I;4R=P[3]J,]ȏ~:3?[ a&e)`e*P[4]T=Cq6R[ ~ޤrXR Հg(t_HZ-Hg M$ãmL5R uk*`%C-E6/%[t X.{8P9Z.vkXŐKjgKZHg(aK9ڦmKjѺm_ \#$5,)-  61eJ,5m| r'= &ڡd%-]J on Xm|{ RҞe $eڧY XYrԮ-a7RK6h>n$5AVڴi*ֆK)mѦtmr1p| q:흺,)Oi*ֺK)ܬ֦K-5r3>0ԔHjJئEZj,%re~/z%jVMڸmrt)3]J,T K֦OvԒgii*bKiNO~%PW0=dii2tJ9Jݕ{7"I P9JKTbu,%r"6RKU}Ij2HKZXJ,妝 XYrP ެ24c%i^IK|.H,%rb:XRl1X4Pe/`x&P8Pj28Mzsx2r\zRPz4J}yP[g=L) .Q[6RjWgp FIH*-`IMRaK9TXcq*I y[jE>cw%gLRԕiFCj-ďa`#e~I j,%r,)?[gp FI˨mnWX#>mʔ XA DZf9,nKҲzIZXJ,L#kiPz4JZF,I,`61%2s $,VOϚ2/UFJfy7K> X+6 STXIeJILzMfKm LRaK9%|4p9LwJI!`NsiazĔ)%- XMq>pk$-$Q2x#N ؎-QR}ᶦHZډ)J,l#i@yn3LN`;nڔ XuX5pF)m|^0(>BHF9(cզEerJI rg7 4I@z0\JIi䵙RR0s;$s6eJ,`n 䂦0a)S)A 1eJ,堌#635RIgpNHuTH_SԕqVe ` &S)>p;S$魁eKIuX`I4춒o}`m$1":PI<[v9^\pTJjriRŭ P{#{R2,`)e-`mgj~1ϣLKam7&U\j/3mJ,`F;M'䱀 .KR#)yhTq;pcK9(q!w?uRR,n.yw*UXj#\]ɱ(qv2=RqfB#iJmmL<]Y͙#$5 uTU7ӦXR+q,`I}qL'`6Kͷ6r,]0S$- [RKR3oiRE|nӦXR.(i:LDLTJjY%o:)6rxzҒqTJjh㞦I.$YR.ʼnGZ\ֿf:%55 I˼!6dKxm4E"mG_ s? .e*?LRfK9%q#uh$)i3ULRfK9yxm܌bj84$i1U^@Wbm4uJ,ҪA>_Ij?1v32[gLRD96oTaR׿N7%L2 NT,`)7&ƝL*꽙yp_$M2#AS,`)7$rkTA29_Iye"|/0t)$n XT2`YJ;6Jx".e<`$) PI$5V4]29SRI>~=@j]lp2`K9Jaai^" Ԋ29ORI%:XV5]JmN9]H;1UC39NI%Xe78t)a;Oi Ҙ>Xt"~G>_mn:%|~ޅ_+]$o)@ǀ{hgN;IK6G&rp)T2i୦KJuv*T=TOSV>(~D>dm,I*Ɛ:R#ۙNI%D>G.n$o;+#RR!.eU˽TRI28t)1LWϚ>IJa3oFbu&:tJ*(F7y0ZR ^p'Ii L24x| XRI%ۄ>S1]Jy[zL$adB7.eh4%%누>WETf+3IR:I3Xה)3אOۦSRO'ٺ)S}"qOr[B7ϙ.edG)^ETR"RtRݜh0}LFVӦDB^k_JDj\=LS(Iv─aTeZ%eUAM-0;~˃@i|l @S4y72>sX-vA}ϛBI!ݎߨWl*)3{'Y|iSlEڻ(5KtSI$Uv02,~ԩ~x;P4ցCrO%tyn425:KMlD ^4JRxSهF_}شJTS6uj+ﷸk$eZO%G*^V2u3EMj3k%)okI]dT)URKDS 7~m@TJR~荪fT"֛L \sM -0T KfJz+nإKr L&j()[E&I ߴ>e FW_kJR|!O:5/2跌3T-'|zX ryp0JS ~^F>-2< `*%ZFP)bSn"L :)+pʷf(pO3TMW$~>@~ū:TAIsV1}S2<%ޟM?@iT ,Eūoz%i~g|`wS(]oȤ8)$ ntu`өe`6yPl IzMI{ʣzʨ )IZ2= ld:5+請M$-ї;U>_gsY$ÁN5WzWfIZ)-yuXIfp~S*IZdt;t>KūKR|$#LcԀ+2\;kJ`]YǔM1B)UbG"IRߊ<xܾӔJ0Z='Y嵤 Leveg)$znV-º^3Ւof#0Tfk^Zs[*I꯳3{)ˬW4Ւ4 OdpbZRS|*I 55#"&-IvT&/윚Ye:i$ 9{LkuRe[I~_\ؠ%>GL$iY8 9ܕ"S`kS.IlC;Ҏ4x&>u_0JLr<J2(^$5L s=MgV ~,Iju> 7r2)^=G$1:3G< `J3~&IR% 6Tx/rIj3O< ʔ&#f_yXJiގNSz; Tx(i8%#4 ~AS+IjerIUrIj362v885+IjAhK__5X%nV%Iͳ-y|7XV2v4fzo_68"S/I-qbf; LkF)KSM$ Ms>K WNV}^`-큧32ŒVؙGdu,^^m%6~Nn&͓3ŒVZMsRpfEW%IwdǀLm[7W&bIRL@Q|)* i ImsIMmKmyV`i$G+R 0tV'!V)֏28vU7͒vHꦼtxꗞT ;S}7Mf+fIRHNZUkUx5SAJㄌ9MqμAIRi|j5)o*^'<$TwI1hEU^c_j?Е$%d`z cyf,XO IJnTgA UXRD }{H}^S,P5V2\Xx`pZ|Yk:$e ~ @nWL.j+ϝYb퇪bZ BVu)u/IJ_ 1[p.p60bC >|X91P:N\!5qUB}5a5ja `ubcVxYt1N0Zzl4]7­gKj]?4ϻ *[bg$)+À*x쳀ogO$~,5 زUS9 lq3+5mgw@np1sso Ӻ=|N6 /g(Wv7U;zωM=wk,0uTg_`_P`uz?2yI!b`kĸSo+Qx%!\οe|އԁKS-s6pu_(ֿ$i++T8=eY; צP+phxWQv*|p1. ά. XRkIQYP,drZ | B%wP|S5`~́@i޾ E;Չaw{o'Q?%iL{u D?N1BD!owPHReFZ* k_-~{E9b-~P`fE{AܶBJAFO wx6Rox5 K5=WwehS8 (JClJ~ p+Fi;ŗo+:bD#g(C"wA^ r.F8L;dzdIHUX݆ϞXg )IFqem%I4dj&ppT{'{HOx( Rk6^C٫O.)3:s(۳(Z?~ٻ89zmT"PLtw䥈5&b<8GZ-Y&K?e8,`I6e(֍xb83 `rzXj)F=l($Ij 2*(F?h(/9ik:I`m#p3MgLaKjc/U#n5S# m(^)=y=đx8ŬI[U]~SцA4p$-F i(R,7Cx;X=cI>{Km\ o(Tv2vx2qiiDJN,Ҏ!1f 5quBj1!8 rDFd(!WQl,gSkL1Bxg''՞^ǘ;pQ P(c_ IRujg(Wz bs#P­rz> k c&nB=q+ؔXn#r5)co*Ũ+G?7< |PQӣ'G`uOd>%Mctz# Ԫڞ&7CaQ~N'-P.W`Oedp03C!IZcIAMPUۀ5J<\u~+{9(FbbyAeBhOSܳ1 bÈT#ŠyDžs,`5}DC-`̞%r&ڙa87QWWp6e7 Rϫ/oY ꇅ Nܶըtc!LA T7V4Jsū I-0Pxz7QNF_iZgúWkG83 0eWr9 X]㾮݁#Jˢ C}0=3ݱtBi]_ &{{[/o[~ \q鯜00٩|cD3=4B_b RYb$óBRsf&lLX#M*C_L܄:gx)WΘsGSbuL rF$9';\4Ɍq'n[%p.Q`u hNb`eCQyQ|l_C>Lb꟟3hSb #xNxSs^ 88|Mz)}:](vbۢamŖ࿥ 0)Q7@0=?^k(*J}3ibkFn HjB׻NO z x}7p 0tfDX.lwgȔhԾŲ }6g E |LkLZteu+=q\Iv0쮑)QٵpH8/2?Σo>Jvppho~f>%bMM}\//":PTc(v9v!gոQ )UfVG+! 35{=x\2+ki,y$~A1iC6#)vC5^>+gǵ@1Hy٪7u;p psϰu/S <aʸGu'tD1ԝI<pg|6j'p:tպhX{o(7v],*}6a_ wXRk,O]Lܳ~Vo45rp"N5k;m{rZbΦ${#)`(Ŵg,;j%6j.pyYT?}-kBDc3qA`NWQū20/^AZW%NQ MI.X#P#,^Ebc&?XR tAV|Y.1!؅⨉ccww>ivl(JT~ u`ٵDm q)+Ri x/x8cyFO!/*!/&,7<.N,YDŽ&ܑQF1Bz)FPʛ?5d 6`kQձ λc؎%582Y&nD_$Je4>a?! ͨ|ȎWZSsv8 j(I&yj Jb5m?HWp=g}G3#|I,5v珿] H~R3@B[☉9Ox~oMy=J;xUVoj bUsl_35t-(ՃɼRB7U!qc+x4H_Qo֮$[GO<4`&č\GOc[.[*Af%mG/ ňM/r W/Nw~B1U3J?P&Y )`ѓZ1p]^l“W#)lWZilUQu`-m|xĐ,_ƪ|9i:_{*(3Gѧ}UoD+>m_?VPۅ15&}2|/pIOʵ> GZ9cmíتmnz)yߐbD >e}:) r|@R5qVSA10C%E_'^8cR7O;6[eKePGϦX7jb}OTGO^jn*媓7nGMC t,k31Rb (vyܴʭ!iTh8~ZYZp(qsRL ?b}cŨʊGO^!rPJO15MJ[c&~Z`"ѓޔH1C&^|Ш|rʼ,AwĴ?b5)tLU)F| &g٣O]oqSUjy(x<Ϳ3 .FSkoYg2 \_#wj{u'rQ>o;%n|F*O_L"e9umDds?.fuuQbIWz |4\0 sb;OvxOSs; G%T4gFRurj(֍ڑb uԖKDu1MK{1^ q; C=6\8FR艇!%\YÔU| 88m)֓NcLve C6z;o&X x59:q61Z(T7>C?gcļxѐ Z oo-08jہ x,`' ҔOcRlf~`jj".Nv+sM_]Zk g( UOPyεx%pUh2(@il0ݽQXxppx-NS( WO+轾 nFߢ3M<;z)FBZjciu/QoF 7R¥ ZFLF~#ȣߨ^<쩡ݛкvџ))ME>ώx4m#!-m!L;vv#~Y[đKmx9.[,UFS CVkZ +ߟrY٧IZd/ioi$%͝ب_ֶX3ܫhNU ZZgk=]=bbJS[wjU()*I =ώ:}-蹞lUj:1}MWm=̛ _ ¾,8{__m{_PVK^n3esw5ӫh#$-q=A̟> ,^I}P^J$qY~Q[ Xq9{#&T.^GVj__RKpn,b=`żY@^՝;z{paVKkQXj/)y TIc&F;FBG7wg ZZDG!x r_tƢ!}i/V=M/#nB8 XxЫ ^@CR<{䤭YCN)eKOSƟa $&g[i3.C6xrOc8TI;o hH6P&L{@q6[ Gzp^71j(l`J}]e6X☉#͕ ׈$AB1Vjh㭦IRsqFBjwQ_7Xk>y"N=MB0 ,C #o6MRc0|$)ف"1!ixY<B9mx `,tA>)5ػQ?jQ?cn>YZe Tisvh# GMމȇp:ԴVuږ8ɼH]C.5C!UV;F`mbBk LTMvPʍϤj?ԯ/Qr1NB`9s"s TYsz &9S%U԰> {<ؿSMxB|H\3@!U| k']$U+> |HHMLޢ?V9iD!-@x TIî%6Z*9X@HMW#?nN ,oe6?tQwڱ.]-y':mW0#!J82qFjH -`ѓ&M0u Uγmxϵ^-_\])@0Rt.8/?ٰCY]x}=sD3ojަЫNuS%U}ԤwHH>ڗjܷ_3gN q7[q2la*ArǓԖ+p8/RGM ]jacd(JhWko6ڎbj]i5Bj3+3!\j1UZLsLTv8HHmup<>gKMJj0@H%,W΃7R) ">c, xixј^ aܖ>H[i.UIHc U1=yW\=S*GR~)AF=`&2h`DzT󑓶J+?W+}C%P:|0H܆}-<;OC[~o.$~i}~HQ TvXΈr=b}$vizL4:ȰT|4~*!oXQR6Lk+#t/g lԁߖ[Jڶ_N$k*". xsxX7jRVbAAʯKҎU3)zSNN _'s?f)6X!%ssAkʱ>qƷb hg %n ~p1REGMHH=BJiy[<5 ǁJҖgKR*倳e~HUy)Ag,K)`Vw6bRR:qL#\rclK/$sh*$ 6덤 KԖc 3Z9=Ɣ=o>X Ώ"1 )a`SJJ6k(<c e{%kϊP+SL'TcMJWRm ŏ"w)qc ef꒵i?b7b('"2r%~HUS1\<(`1Wx9=8HY9m:X18bgD1u ~|H;K-Uep,, C1 RV.MR5άh,tWO8WC$ XRVsQS]3GJ|12 [vM :k#~tH30Rf-HYݺ-`I9%lIDTm\ S{]9gOڒMNCV\G*2JRŨ;Rҏ^ڽ̱mq1Eu?To3I)y^#jJw^Ńj^vvlB_⋌P4x>0$c>K†Aļ9s_VjTt0l#m>E-,,x,-W)سo&96RE XR.6bXw+)GAEvL)͞K4$p=Ũi_ѱOjb HY/+@θH9޼]Nԥ%n{ &zjT? Ty) s^ULlb,PiTf^<À] 62R^V7)S!nllS6~͝V}-=%* ʻ>G DnK<y&>LPy7'r=Hj 9V`[c"*^8HpcO8bnU`4JȪAƋ#1_\ XϘHPRgik(~G~0DAA_2p|J묭a2\NCr]M_0 ^T%e#vD^%xy-n}-E\3aS%yN!r_{ )sAw ڼp1pEAk~v<:`'ӭ^5 ArXOI驻T (dk)_\ PuA*BY]yB"l\ey hH*tbK)3 IKZ򹞋XjN n *n>k]X_d!ryBH ]*R 0(#'7 %es9??ښFC,ՁQPjARJ\Ρw K#jahgw;2$l*) %Xq5!U᢯6Re] |0[__64ch&_}iL8KEgҎ7 M/\`|.p,~`a=BR?xܐrQ8K XR2M8f ?`sgWS%" Ԉ 7R%$ N}?QL1|-эټwIZ%pvL3Hk>,ImgW7{E xPHx73RA @RS CC !\ȟ5IXR^ZxHл$Q[ŝ40 (>+ _C >BRt<,TrT {O/H+˟Pl6 I B)/VC<6a2~(XwV4gnXR ϱ5ǀHٻ?tw똤Eyxp{#WK qG%5],(0ӈH HZ])ג=K1j&G(FbM@)%I` XRg ʔ KZG(vP,<`[ Kn^ SJRsAʠ5xՅF`0&RbV tx:EaUE/{fi2;.IAwW8/tTxAGOoN?G}l L(n`Zv?pB8K_gI+ܗ #i?ޙ.) p$utc ~DžfՈEo3l/)I-U?aԅ^jxArA ΧX}DmZ@QLےbTXGd.^|xKHR{|ΕW_h] IJ`[G9{).y) 0X YA1]qp?p_k+J*Y@HI>^?gt.06Rn ,` ?);p pSF9ZXLBJPWjgQ|&)7! HjQt<| ؅W5 x W HIzYoVMGP Hjn`+\(dNW)F+IrS[|/a`K|ͻ0Hj{R,Q=\ (F}\WR)AgSG`IsnAR=|8$}G(vC$)s FBJ?]_u XRvύ6z ŨG[36-T9HzpW̞ú Xg큽=7CufzI$)ki^qk-) 0H*N` QZkk]/tnnsI^Gu't=7$ Z;{8^jB% IItRQS7[ϭ3 $_OQJ`7!]W"W,)Iy W AJA;KWG`IY{8k$I$^%9.^(`N|LJ%@$I}ֽp=FB*xN=gI?Q{٥4B)mw $Igc~dZ@G9K X?7)aK%݅K$IZ-`IpC U6$I\0>!9k} Xa IIS0H$I H ?1R.Чj:4~Rw@p$IrA*u}WjWFPJ$I➓/6#! LӾ+ X36x8J |+L;v$Io4301R20M I$-E}@,pS^ޟR[/s¹'0H$IKyfŸfVOπFT*a$I>He~VY/3R/)>d$I>28`Cjw,n@FU*9ttf$I~<;=/4RD~@ X-ѕzἱI$: ԍR a@b X{+Qxuq$IЛzo /~3\8ڒ4BN7$IҀj V]n18H$IYFBj3̵̚ja pp $Is/3R Ӻ-Yj+L;.0ŔI$Av? #!5"aʄj}UKmɽH$IjCYs?h$IDl843.v}m7UiI=&=0Lg0$I4: embe` eQbm0u? $IT!Sƍ'-sv)s#C0:XB2a w I$zbww{."pPzO =Ɔ\[ o($Iaw]`E).Kvi:L*#gР7[$IyGPI=@R 4yR~̮´cg I$I/<tPͽ hDgo 94Z^k盇΄8I56^W$I^0̜N?4*H`237}g+hxoq)SJ@p|` $I%>-hO0eO>\ԣNߌZD6R=K ~n($I$y3D>o4b#px2$yڪtzW~a $I~?x'BwwpH$IZݑnC㧄Pc_9sO gwJ=l1:mKB>Ab<4Lp$Ib o1ZQ@85b̍ S'F,Fe,^I$IjEdù{l4 8Ys_s Z8.x m"+{~?q,Z D!I$ϻ'|XhB)=…']M>5 rgotԎ 獽PH$IjIPhh)n#cÔqA'ug5qwU&rF|1E%I$%]!'3AFD/;Ck_`9 v!ٴtPV;x`'*bQa w I$Ix5 FC3D_~A_#O݆DvV?<qw+I$I{=Z8".#RIYyjǪ=fDl9%M,a8$I$Ywi[7ݍFe$s1ՋBVA?`]#!oz4zjLJo8$I$%@3jAa4(o ;p,,dya=F9ً[LSPH$IJYЉ+3> 5"39aZ<ñh!{TpBGkj}Sp $IlvF.F$I z< '\K*qq.f<2Y!S"-\I$IYwčjF$ w9 \ߪB.1v!Ʊ?+r:^!I$BϹB H"B;L'G[ 4U#5>੐)|#o0aڱ$I>}k&1`U#V?YsV x>{t1[I~D&(I$I/{H0fw"q"y%4 IXyE~M3 8XψL}qE$I[> nD?~sf ]o΁ cT6"?'_Ἣ $I>~.f|'!N?⟩0G KkXZE]ޡ;/&?k OۘH$IRۀwXӨ<7@PnS04aӶp.:@\IWQJ6sS%I$e5ڑv`3:x';wq_vpgHyXZ 3gЂ7{{EuԹn±}$I$8t;b|591nءQ"P6O5i }iR̈́%Q̄p!I䮢]O{H$IRϻ9s֧ a=`- aB\X0"+5"C1Hb?߮3x3&gşggl_hZ^,`5?ߎvĸ%̀M!OZC2#0x LJ0 Gw$I$I}<{Eb+y;iI,`ܚF:5ܛA8-O-|8K7s|#Z8a&><a&/VtbtLʌI$I$I$I$I$I$IRjDD%tEXtdate:create2022-05-31T04:40:26+00:00!Î%tEXtdate:modify2022-05-31T04:40:26+00:00|{2IENDB`Mini Shell

HOME


Mini Shell 1.0
DIR:/opt/cpanel/ea-openssl11/share/doc/openssl/html/man3/
Upload File :
Current File : //opt/cpanel/ea-openssl11/share/doc/openssl/html/man3/SSL_CTX_set_tlsext_ticket_key_cb.html
<?xml version="1.0" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>SSL_CTX_set_tlsext_ticket_key_cb</title>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<link rev="made" href="mailto:root@localhost" />
</head>

<body style="background-color: white">



<ul id="index">
  <li><a href="#NAME">NAME</a></li>
  <li><a href="#SYNOPSIS">SYNOPSIS</a></li>
  <li><a href="#DESCRIPTION">DESCRIPTION</a></li>
  <li><a href="#NOTES">NOTES</a></li>
  <li><a href="#RETURN-VALUES">RETURN VALUES</a></li>
  <li><a href="#EXAMPLES">EXAMPLES</a></li>
  <li><a href="#SEE-ALSO">SEE ALSO</a></li>
  <li><a href="#COPYRIGHT">COPYRIGHT</a></li>
</ul>

<h1 id="NAME">NAME</h1>

<p>SSL_CTX_set_tlsext_ticket_key_cb - set a callback for session ticket processing</p>

<h1 id="SYNOPSIS">SYNOPSIS</h1>

<pre><code> #include &lt;openssl/tls1.h&gt;

 long SSL_CTX_set_tlsext_ticket_key_cb(SSL_CTX sslctx,
     int (*cb)(SSL *s, unsigned char key_name[16],
               unsigned char iv[EVP_MAX_IV_LENGTH],
               EVP_CIPHER_CTX *ctx, HMAC_CTX *hctx, int enc));</code></pre>

<h1 id="DESCRIPTION">DESCRIPTION</h1>

<p>SSL_CTX_set_tlsext_ticket_key_cb() sets a callback function <i>cb</i> for handling session tickets for the ssl context <i>sslctx</i>. Session tickets, defined in RFC5077 provide an enhanced session resumption capability where the server implementation is not required to maintain per session state. It only applies to TLS and there is no SSLv3 implementation.</p>

<p>The callback function <i>cb</i> will be called for every client instigated TLS session when session ticket extension is presented in the TLS hello message. It is the responsibility of this function to create or retrieve the cryptographic parameters and to maintain their state.</p>

<p>The OpenSSL library uses your callback function to help implement a common TLS ticket construction state according to RFC5077 Section 4 such that per session state is unnecessary and a small set of cryptographic variables needs to be maintained by the callback function implementation.</p>

<p>In order to reuse a session, a TLS client must send the a session ticket extension to the server. The client can only send exactly one session ticket. The server, through the callback function, either agrees to reuse the session ticket information or it starts a full TLS handshake to create a new session ticket.</p>

<p>Before the callback function is started <i>ctx</i> and <i>hctx</i> have been initialised with <a href="../man3/EVP_CIPHER_CTX_reset.html">EVP_CIPHER_CTX_reset(3)</a> and <a href="../man3/HMAC_CTX_reset.html">HMAC_CTX_reset(3)</a> respectively.</p>

<p>For new sessions tickets, when the client doesn&#39;t present a session ticket, or an attempted retrieval of the ticket failed, or a renew option was indicated, the callback function will be called with <i>enc</i> equal to 1. The OpenSSL library expects that the function will set an arbitrary <i>name</i>, initialize <i>iv</i>, and set the cipher context <i>ctx</i> and the hash context <i>hctx</i>.</p>

<p>The <i>name</i> is 16 characters long and is used as a key identifier.</p>

<p>The <i>iv</i> length is the length of the IV of the corresponding cipher. The maximum IV length is <b>EVP_MAX_IV_LENGTH</b> bytes defined in <b>evp.h</b>.</p>

<p>The initialization vector <i>iv</i> should be a random value. The cipher context <i>ctx</i> should use the initialisation vector <i>iv</i>. The cipher context can be set using <a href="../man3/EVP_EncryptInit_ex.html">EVP_EncryptInit_ex(3)</a>. The hmac context can be set using <a href="../man3/HMAC_Init_ex.html">HMAC_Init_ex(3)</a>.</p>

<p>When the client presents a session ticket, the callback function with be called with <i>enc</i> set to 0 indicating that the <i>cb</i> function should retrieve a set of parameters. In this case <i>name</i> and <i>iv</i> have already been parsed out of the session ticket. The OpenSSL library expects that the <i>name</i> will be used to retrieve a cryptographic parameters and that the cryptographic context <i>ctx</i> will be set with the retrieved parameters and the initialization vector <i>iv</i>. using a function like <a href="../man3/EVP_DecryptInit_ex.html">EVP_DecryptInit_ex(3)</a>. The <i>hctx</i> needs to be set using <a href="../man3/HMAC_Init_ex.html">HMAC_Init_ex(3)</a>.</p>

<p>If the <i>name</i> is still valid but a renewal of the ticket is required the callback function should return 2. The library will call the callback again with an argument of enc equal to 1 to set the new ticket.</p>

<p>The return value of the <i>cb</i> function is used by OpenSSL to determine what further processing will occur. The following return values have meaning:</p>

<dl>

<dt id="pod2">2</dt>
<dd>

<p>This indicates that the <i>ctx</i> and <i>hctx</i> have been set and the session can continue on those parameters. Additionally it indicates that the session ticket is in a renewal period and should be replaced. The OpenSSL library will call <i>cb</i> again with an enc argument of 1 to set the new ticket (see RFC5077 3.3 paragraph 2).</p>

</dd>
<dt id="pod1">1</dt>
<dd>

<p>This indicates that the <i>ctx</i> and <i>hctx</i> have been set and the session can continue on those parameters.</p>

</dd>
<dt id="pod0">0</dt>
<dd>

<p>This indicates that it was not possible to set/retrieve a session ticket and the SSL/TLS session will continue by negotiating a set of cryptographic parameters or using the alternate SSL/TLS resumption mechanism, session ids.</p>

<p>If called with enc equal to 0 the library will call the <i>cb</i> again to get a new set of parameters.</p>

</dd>
<dt id="less-than-0">less than 0</dt>
<dd>

<p>This indicates an error.</p>

</dd>
</dl>

<h1 id="NOTES">NOTES</h1>

<p>Session resumption shortcuts the TLS so that the client certificate negotiation don&#39;t occur. It makes up for this by storing client certificate an all other negotiated state information encrypted within the ticket. In a resumed session the applications will have all this state information available exactly as if a full negotiation had occurred.</p>

<p>If an attacker can obtain the key used to encrypt a session ticket, they can obtain the master secret for any ticket using that key and decrypt any traffic using that session: even if the cipher suite supports forward secrecy. As a result applications may wish to use multiple keys and avoid using long term keys stored in files.</p>

<p>Applications can use longer keys to maintain a consistent level of security. For example if a cipher suite uses 256 bit ciphers but only a 128 bit ticket key the overall security is only 128 bits because breaking the ticket key will enable an attacker to obtain the session keys.</p>

<h1 id="RETURN-VALUES">RETURN VALUES</h1>

<p>Returns 1 to indicate the callback function was set and 0 otherwise.</p>

<h1 id="EXAMPLES">EXAMPLES</h1>

<p>Reference Implementation:</p>

<pre><code> SSL_CTX_set_tlsext_ticket_key_cb(SSL, ssl_tlsext_ticket_key_cb);
 ...

 static int ssl_tlsext_ticket_key_cb(SSL *s, unsigned char key_name[16],
                                     unsigned char *iv, EVP_CIPHER_CTX *ctx,
                                     HMAC_CTX *hctx, int enc)
 {
     your_type_t *key; /* something that you need to implement */

     if (enc) { /* create new session */
         if (RAND_bytes(iv, EVP_MAX_IV_LENGTH) &lt;= 0)
             return -1; /* insufficient random */

         key = currentkey(); /* something that you need to implement */
         if (key == NULL) {
             /* current key doesn&#39;t exist or isn&#39;t valid */
             key = createkey(); /*
                                 * Something that you need to implement.
                                 * createkey needs to initialise a name,
                                 * an aes_key, a hmac_key and optionally
                                 * an expire time.
                                 */
             if (key == NULL) /* key couldn&#39;t be created */
                 return 0;
         }
         memcpy(key_name, key-&gt;name, 16);

         EVP_EncryptInit_ex(&amp;ctx, EVP_aes_256_cbc(), NULL, key-&gt;aes_key, iv);
         HMAC_Init_ex(&amp;hctx, key-&gt;hmac_key, 32, EVP_sha256(), NULL);

         return 1;

     } else { /* retrieve session */
         time_t t = time(NULL);
         key = findkey(key_name); /* something that you need to implement */

         if (key == NULL || key-&gt;expire &lt; t)
             return 0;

         HMAC_Init_ex(&amp;hctx, key-&gt;hmac_key, 32, EVP_sha256(), NULL);
         EVP_DecryptInit_ex(&amp;ctx, EVP_aes_256_cbc(), NULL, key-&gt;aes_key, iv);

         if (key-&gt;expire &lt; t - RENEW_TIME) { /* RENEW_TIME: implement */
             /*
              * return 2 - This session will get a new ticket even though the
              * current one is still valid.
              */
             return 2;
         }
         return 1;
     }
 }</code></pre>

<h1 id="SEE-ALSO">SEE ALSO</h1>

<p><a href="../man7/ssl.html">ssl(7)</a>, <a href="../man3/SSL_set_session.html">SSL_set_session(3)</a>, <a href="../man3/SSL_session_reused.html">SSL_session_reused(3)</a>, <a href="../man3/SSL_CTX_add_session.html">SSL_CTX_add_session(3)</a>, <a href="../man3/SSL_CTX_sess_number.html">SSL_CTX_sess_number(3)</a>, <a href="../man3/SSL_CTX_sess_set_get_cb.html">SSL_CTX_sess_set_get_cb(3)</a>, <a href="../man3/SSL_CTX_set_session_id_context.html">SSL_CTX_set_session_id_context(3)</a>,</p>

<h1 id="COPYRIGHT">COPYRIGHT</h1>

<p>Copyright 2014-2021 The OpenSSL Project Authors. All Rights Reserved.</p>

<p>Licensed under the OpenSSL license (the &quot;License&quot;). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p>


</body>

</html>