act-omega-grid.php

<?php

$input['HIP290'] = 'YMPZ PZ YVWXBHYBZ HGHSIVS DVWR VS LZYHGQPZMPSN H SLD STQH KPNBWLMLHI SV LCPZYPSN JHSIPIHYLZ MHAL ZBKKPJPLSY ZBUUVWY YV WLUQHJL YMLYH ZLALS MPZ THWYFWIVT DHZ LCULJYLI GBY MHZ BSKVWYBSHYLQF MHUULSLI HMLHI VK ZJMLIBQL KVW SVD JVSJLSYWHYL VS HAVPIPSN ILYLJYPVS YMLWL DPQQ GL VYMLW JMHSJLZ YV WLTVAL YML WLTHPSPSN IBAHQS';
$input['SAFFRON'] = '5GF5M1 2DF 1MW2GD4 1R13K Y45 Q1C2 D4 Q2MJ L2 3C2 M2SD V1J3D4M B3DQ LY S1L3MY D4 1C43T 33FF H52FD34K3KR BQ1D 3S DQ1D M1KT15 B4L1K G21MMY V1K VG1VN 45G 4L2R1 RG3T N1GM JG4L3F2T L2 DQ1D B1F 3LJ4FF3WM2 Y45 NK4B 3C2 1MB1YF W22K M4Y1M D4 Y45 1KT DQ2 4DQ2G M4GTF W5D 3 K2C2G TG21LD 45G B4GN V45MT 2ZJ4F2 L2 J2GF4K1MMY T4 F4L2DQ3KR';
$input['MAIDJIN'] = 'F2N2Q2N DT2FM T2R2TW2QJ W2 V2Q2W2T Q2TX2 Y2X2 K2G W2 G2VD2QG WK2 T2P22Q2QJ WT22Q2QJ F2PRV PB V2NG22TV F22JKW 2QG 2Z2F2W2G V2X2T2N 2FW 2J2QWV 2P2QJ WK2 N2W2VW 2QW2M2 2H B22 Y2QW 2V W2 F2QW2Q22 Y2TM2QJ H2T WK2 N2TGQ 2H T2VW2T2W22Q Y2 P2VW T2Q2J2W22T2 22T 2JT22P2QW WK2 F2TT2QW V2W22W22Q 2V Q2W V2VW22Q2DN2'

 
$keys['HIP290'] = [
'A' => 'H',
'B' => 'G',
'C' => 'J',
'E' => 'L',
'F' => 'K',
'L' => 'Q',
'M' => 'T',
'O' => 'V',
'P' => 'U',
'Q' => 'X',
'S' => 'Z',
'T' => 'Y',
'U' => 'B',
'V' => 'A',
'W' => 'D',
// found by me
 ' ' => ' ',
 'H' => 'M',
 'I' => 'P',
 'R' => 'W',
 'N' => 'S',
 'D' => 'I',
 'K' => 'R',
 'X' => 'C',
 'G' => 'N',
 'Y' => 'F',
];

$keys['SAFFRON'] = [
 'F'=>'S',
 'G'=>'R',
 'I'=>'3',
 'J'=>'P',
 'K'=>'N',
 'O'=>'4',
 'P'=>'J',
 'Q'=>'H',
 'R'=>'G',
 'U'=>'S',
 'V'=>'C',
 'W'=>'B',
 'X'=>'Z',
 'Y'=>'Y',
 // found by me
 ' ' => ' ',
 'U' => '5',
 'T' => 'D',
 'H' => 'Q',
 'A' => '1',
 'N' => 'K',
 'E' => '2',
 'L' => 'M',
 'M' => 'L',
 'C' => 'V',
 'S' => 'F',
 'D' => 'T',
 'B' => 'W',
    ];
    
$keys['MAIDJIN'] = [
'B' > 'D',
'C/CH' > 'F',
'D' > 'G',
'E' > '2',
'I' > '2',
'J' > 'L',
'K' > 'M',
'M' > 'P',
'O' > '2',
'QU' > 'R',
'R' > 'S',
'T/TH' > 'W',
'X' > 'Z',
'Y' > 'B',
// found by me
];

foreach( $input as $id => $message){
    $toParse = str_split($message);
    $output = '';
    $missing = '';
    foreach( $toParse as $letter){
        $replacement = array_searcH($letter, $keys[$id]);
        if( $replacement ){
            $output .= $replacement;
        } else {
            $output  .= '_';
            $missing .= $letter;
       }
    }

    echo $id.PHP_EOL.$message.PHP_EOL.$output.PHP_EOL.$missing.PHP_EOL;
}