{VERSION 3 0 "SUN SPARC SOLARIS" "3.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 }{CSTYLE "2D Math" -1 2 "Times" 0 1 0 0 0 0 0 0 2 0 0 0 0 0 0 }{CSTYLE "2D Comment" 2 18 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 } {CSTYLE "2D Output" 2 20 "" 0 1 0 0 255 1 0 0 0 0 0 0 0 0 0 }{CSTYLE " " -1 256 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 257 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 264 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 265 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 266 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 267 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "Maple Output" 0 11 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 }3 3 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "" 0 256 1 {CSTYLE "" -1 -1 "" 1 14 0 0 0 0 0 0 0 0 0 0 0 0 0 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "" 0 257 1 {CSTYLE "" -1 -1 "" 1 14 0 0 0 0 0 0 0 0 0 0 0 0 0 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 256 "" 0 "" {TEXT -1 25 "1. An RSA public key has " }{TEXT 256 9 "n = 25021" }{TEXT -1 5 " and " }{TEXT 257 6 "a = 29" }{TEXT -1 38 ". Find the corresponding private key." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "n := 25021; a := 29;" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"nG\"&@]#" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"aG \"#H" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 11 "ifactor(n);" }} {PARA 11 "" 1 "" {XPPMATH 20 "6#*&-%!G6#\"$J\"\"\"\"-F%6#\"$\">F(" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "p := 131; q := 191;" }} {PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"pG\"$J\"" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"qG\"$\">" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "phi := (p-1)*(q-1);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%$phiG\"&+ Z#" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "x := modp(1/a, phi); " }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"xG\"%p$*" }}}{EXCHG {PARA 0 " " 0 "" {TEXT -1 30 "Therefore the private key has " }{TEXT 266 9 "n = \+ 25021" }{TEXT -1 5 " and " }{TEXT 267 8 "x = 9369" }{TEXT -1 1 "." }}} {EXCHG {PARA 257 "" 0 "" {TEXT -1 22 "2. Encode the integer " } {XPPEDIT 18 0 "beta;" "6#%%betaG" }{TEXT -1 1 " " }{TEXT 264 5 "= 271 " }{TEXT -1 97 " using the public key. What do you get? Decode this u sing the private key you found. Do you get " }{TEXT 265 3 "271" } {TEXT -1 6 " back?" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "beta \+ := 271;" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%%betaG\"$r#" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "m := modp(beta &^ a, n);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"mG\"%Jf" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "modp(m &^ x, n);" }}{PARA 11 "" 1 "" {XPPMATH 20 "6# \"$r#" }}}}{MARK "11" 0 }{VIEWOPTS 1 1 0 1 1 1803 }