1  import * as forge from 'node-forge'
 2  
 3  const rsa = forge.pki.rsa
 4  
 5  function scrambleModulus( values: Array<number> ) : Buffer {
 6      let scrambledMod = Buffer.from( values )
 7  
 8      if ( ( scrambledMod.length === 0x81 ) && ( scrambledMod[ 0 ] === 0x00 ) ) {
 9          scrambledMod = scrambledMod.subarray( 1 )
10      }
11      // step 1 : 0x4d-0x50 <-> 0x00-0x04
12      for ( let i = 0; i < 4; i++ ) {
13          let temp = scrambledMod[ i ]
14          scrambledMod[ i ] = scrambledMod[ 0x4d + i ]
15          scrambledMod[ 0x4d + i ] = temp
16      }
17      // step 2 : xor first 0x40 bytes with last 0x40 bytes
18      for ( let i = 0; i < 0x40; i++ ) {
19          scrambledMod[ i ] = scrambledMod[ i ] ^ scrambledMod[ 0x40 + i ]
20      }
21      // step 3 : xor bytes 0x0d-0x10 with bytes 0x34-0x38
22      for ( let i = 0; i < 4; i++ ) {
23          scrambledMod[ 0x0d + i ] = scrambledMod[ 0x0d + i ] ^ scrambledMod[ 0x34 + i ]
24      }
25      // step 4 : xor last 0x40 bytes with first 0x40 bytes
26      for ( let i = 0; i < 0x40; i++ ) {
27          scrambledMod[ 0x40 + i ] = scrambledMod[ 0x40 + i ] ^ scrambledMod[ i ]
28      }
29  
30      return scrambledMod
31  }
32  
33  export interface L2KeyPair {
34      value: any
35      modulus: Buffer
36  }
37  
38  
39  export function createKeyPair() :L2KeyPair {
40      let value = rsa.generateKeyPair( { bits: 1024, e: 0x10001 } )
41      return {
42          value,
43          modulus: scrambleModulus( value.publicKey.n.toByteArray() )
44      }
45  }