Develop own “Hash” algorithm

So I got a integer variable between 1 and 10,000.

I'd like to convert every number to a unique! hash value that has a fixed length and has a custom charset (includes all alphabetic lowercase and uppercase characters).

So:

n=10 could get to result="AVduujANNiO"

n=4507 could get to result="BciidEPpaEo"

I do not really know how to develop an algorithm like this so this is all I got so far. I think the algorithm should work but of course I get a integer value as hash - not a alphabetic value. No idea how to fix this and how to pad the result to give it a fixed length.

I really hope somebody is able to help me.

let value = "3325";





var getHash = function(value) {

  let hash = 0;

  for (let i = 0; i < value.length; i++) {

    let char = value.charCodeAt(i);

    hash = (hash << 6) + char + (char << 14);

    hash=-hash

  } return hash;

};



console.log(getHash(value))

edited Nov 12 '18 at 20:11

asked Nov 12 '18 at 19:54

jonas00

8931619

1

May I ask why you want to do this? It seems pretty wasteful to use an 11 byte string to represent a 14 bit number.
– hager
Nov 12 '18 at 20:04

1

Easy enough, as long as you have at least 10000 possible hash values to choose from. That depends on your fixed length and chosen charset. If your charset includes only the 62 alphanumeric chars then you need at least 3 characters. Will that do? Note that this is "base conversion", not "hashing".
– Matt Timmermans
Nov 12 '18 at 20:04

3

Use your integer to seed a PRNG, then simply use it to fetch N "random" chars from alphabet string.
– Sergio Tulentsev
Nov 12 '18 at 20:04

2

Why are you trying to make your own hash algorithm? (I hope you're not trying to roll your own crypto). Also what properties should your hash function have?
– Bergi
Nov 12 '18 at 20:07

4

I wouldn't call this hashing at all. It sounds like you really want to convert to an arbitrary base using arbitrary characters as digits.
– TKK
Nov 12 '18 at 20:20

|
show 10 more comments

So I got a integer variable between 1 and 10,000.

I'd like to convert every number to a unique! hash value that has a fixed length and has a custom charset (includes all alphabetic lowercase and uppercase characters).

So:

n=10 could get to result="AVduujANNiO"

n=4507 could get to result="BciidEPpaEo"

I really hope somebody is able to help me.

let value = "3325";





var getHash = function(value) {

  let hash = 0;

  for (let i = 0; i < value.length; i++) {

    let char = value.charCodeAt(i);

    hash = (hash << 6) + char + (char << 14);

    hash=-hash

  } return hash;

};



console.log(getHash(value))

edited Nov 12 '18 at 20:11

asked Nov 12 '18 at 19:54

jonas00

8931619

1

May I ask why you want to do this? It seems pretty wasteful to use an 11 byte string to represent a 14 bit number.
– hager
Nov 12 '18 at 20:04

1

Easy enough, as long as you have at least 10000 possible hash values to choose from. That depends on your fixed length and chosen charset. If your charset includes only the 62 alphanumeric chars then you need at least 3 characters. Will that do? Note that this is "base conversion", not "hashing".
– Matt Timmermans
Nov 12 '18 at 20:04

3

Use your integer to seed a PRNG, then simply use it to fetch N "random" chars from alphabet string.
– Sergio Tulentsev
Nov 12 '18 at 20:04

2

Why are you trying to make your own hash algorithm? (I hope you're not trying to roll your own crypto). Also what properties should your hash function have?
– Bergi
Nov 12 '18 at 20:07

4

I wouldn't call this hashing at all. It sounds like you really want to convert to an arbitrary base using arbitrary characters as digits.
– TKK
Nov 12 '18 at 20:20

|
show 10 more comments

So I got a integer variable between 1 and 10,000.

I'd like to convert every number to a unique! hash value that has a fixed length and has a custom charset (includes all alphabetic lowercase and uppercase characters).

So:

n=10 could get to result="AVduujANNiO"

n=4507 could get to result="BciidEPpaEo"

I really hope somebody is able to help me.

let value = "3325";





var getHash = function(value) {

  let hash = 0;

  for (let i = 0; i < value.length; i++) {

    let char = value.charCodeAt(i);

    hash = (hash << 6) + char + (char << 14);

    hash=-hash

  } return hash;

};



console.log(getHash(value))

edited Nov 12 '18 at 20:11

asked Nov 12 '18 at 19:54

jonas00

8931619

So I got a integer variable between 1 and 10,000.

I'd like to convert every number to a unique! hash value that has a fixed length and has a custom charset (includes all alphabetic lowercase and uppercase characters).

So:

n=10 could get to result="AVduujANNiO"

n=4507 could get to result="BciidEPpaEo"

I really hope somebody is able to help me.

let value = "3325";





var getHash = function(value) {

  let hash = 0;

  for (let i = 0; i < value.length; i++) {

    let char = value.charCodeAt(i);

    hash = (hash << 6) + char + (char << 14);

    hash=-hash

  } return hash;

};



console.log(getHash(value))

let value = "3325";





var getHash = function(value) {

  let hash = 0;

  for (let i = 0; i < value.length; i++) {

    let char = value.charCodeAt(i);

    hash = (hash << 6) + char + (char << 14);

    hash=-hash

  } return hash;

};



console.log(getHash(value))

let value = "3325";





var getHash = function(value) {

  let hash = 0;

  for (let i = 0; i < value.length; i++) {

    let char = value.charCodeAt(i);

    hash = (hash << 6) + char + (char << 14);

    hash=-hash

  } return hash;

};



console.log(getHash(value))

javascript string algorithm math hash

edited Nov 12 '18 at 20:11

asked Nov 12 '18 at 19:54

jonas00

8931619

edited Nov 12 '18 at 20:11

asked Nov 12 '18 at 19:54

jonas00

8931619

edited Nov 12 '18 at 20:11

asked Nov 12 '18 at 19:54

jonas00

8931619

asked Nov 12 '18 at 19:54

jonas00

8931619

asked Nov 12 '18 at 19:54

jonas00

8931619

1

May I ask why you want to do this? It seems pretty wasteful to use an 11 byte string to represent a 14 bit number.
– hager
Nov 12 '18 at 20:04

1

Easy enough, as long as you have at least 10000 possible hash values to choose from. That depends on your fixed length and chosen charset. If your charset includes only the 62 alphanumeric chars then you need at least 3 characters. Will that do? Note that this is "base conversion", not "hashing".
– Matt Timmermans
Nov 12 '18 at 20:04

3

Use your integer to seed a PRNG, then simply use it to fetch N "random" chars from alphabet string.
– Sergio Tulentsev
Nov 12 '18 at 20:04

2

Why are you trying to make your own hash algorithm? (I hope you're not trying to roll your own crypto). Also what properties should your hash function have?
– Bergi
Nov 12 '18 at 20:07

4

I wouldn't call this hashing at all. It sounds like you really want to convert to an arbitrary base using arbitrary characters as digits.
– TKK
Nov 12 '18 at 20:20

|
show 10 more comments

1

May I ask why you want to do this? It seems pretty wasteful to use an 11 byte string to represent a 14 bit number.
– hager
Nov 12 '18 at 20:04

1

Easy enough, as long as you have at least 10000 possible hash values to choose from. That depends on your fixed length and chosen charset. If your charset includes only the 62 alphanumeric chars then you need at least 3 characters. Will that do? Note that this is "base conversion", not "hashing".
– Matt Timmermans
Nov 12 '18 at 20:04

3

Use your integer to seed a PRNG, then simply use it to fetch N "random" chars from alphabet string.
– Sergio Tulentsev
Nov 12 '18 at 20:04

2

Why are you trying to make your own hash algorithm? (I hope you're not trying to roll your own crypto). Also what properties should your hash function have?
– Bergi
Nov 12 '18 at 20:07

4

I wouldn't call this hashing at all. It sounds like you really want to convert to an arbitrary base using arbitrary characters as digits.
– TKK
Nov 12 '18 at 20:20

May I ask why you want to do this? It seems pretty wasteful to use an 11 byte string to represent a 14 bit number.
– hager
Nov 12 '18 at 20:04

Easy enough, as long as you have at least 10000 possible hash values to choose from. That depends on your fixed length and chosen charset. If your charset includes only the 62 alphanumeric chars then you need at least 3 characters. Will that do? Note that this is "base conversion", not "hashing".
– Matt Timmermans
Nov 12 '18 at 20:04

Use your integer to seed a PRNG, then simply use it to fetch N "random" chars from alphabet string.
– Sergio Tulentsev
Nov 12 '18 at 20:04

Why are you trying to make your own hash algorithm? (I hope you're not trying to roll your own crypto). Also what properties should your hash function have?
– Bergi
Nov 12 '18 at 20:07

I wouldn't call this hashing at all. It sounds like you really want to convert to an arbitrary base using arbitrary characters as digits.
– TKK
Nov 12 '18 at 20:20

|
show 10 more comments

1 Answer
1

active

oldest

votes

Here's a hash function that seems to do what you are asking for :) As a bonus, it offers no collisions til 100,000.

function h(n){

  let s = [

    '0101000', '1011010', '0011111',

    '1100001', '1100101', '1011001',

    '1110011', '1010101', '1000111',

    '0001100', '1001000'].map(x => parseInt(x, 2));

    

  let m = parseInt('101', 2);

  

  s = s.map(x => {

    n ^= m;

    m <<= 1;

    return (x ^ n) % 52;

  });



  return s.map(x =>

    String.fromCharCode(x > 25 ? 71 + x : 65 + x)

  ).join('');

}



const s = {};



for (let j=1; j <=10000; j++){

  let hash = h(j);

  

  if (s[hash])

    console.log('Collision! ' + j + ' <-> ' + s[hash]);

    

  s[hash] = j;

}



console.log('Done. No collisions below 10000.');



for (let j=1; j <11; j++)

  console.log(j, h(j));

edited Nov 13 '18 at 6:16

answered Nov 13 '18 at 3:09

גלעד ברקן

12.3k21439

add a comment |

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1 Answer
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oldest

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1 Answer
1

active

oldest

votes

Here's a hash function that seems to do what you are asking for :) As a bonus, it offers no collisions til 100,000.

function h(n){

  let s = [

    '0101000', '1011010', '0011111',

    '1100001', '1100101', '1011001',

    '1110011', '1010101', '1000111',

    '0001100', '1001000'].map(x => parseInt(x, 2));

    

  let m = parseInt('101', 2);

  

  s = s.map(x => {

    n ^= m;

    m <<= 1;

    return (x ^ n) % 52;

  });



  return s.map(x =>

    String.fromCharCode(x > 25 ? 71 + x : 65 + x)

  ).join('');

}



const s = {};



for (let j=1; j <=10000; j++){

  let hash = h(j);

  

  if (s[hash])

    console.log('Collision! ' + j + ' <-> ' + s[hash]);

    

  s[hash] = j;

}



console.log('Done. No collisions below 10000.');



for (let j=1; j <11; j++)

  console.log(j, h(j));

edited Nov 13 '18 at 6:16

answered Nov 13 '18 at 3:09

גלעד ברקן

12.3k21439

add a comment |

Here's a hash function that seems to do what you are asking for :) As a bonus, it offers no collisions til 100,000.

function h(n){

  let s = [

    '0101000', '1011010', '0011111',

    '1100001', '1100101', '1011001',

    '1110011', '1010101', '1000111',

    '0001100', '1001000'].map(x => parseInt(x, 2));

    

  let m = parseInt('101', 2);

  

  s = s.map(x => {

    n ^= m;

    m <<= 1;

    return (x ^ n) % 52;

  });



  return s.map(x =>

    String.fromCharCode(x > 25 ? 71 + x : 65 + x)

  ).join('');

}



const s = {};



for (let j=1; j <=10000; j++){

  let hash = h(j);

  

  if (s[hash])

    console.log('Collision! ' + j + ' <-> ' + s[hash]);

    

  s[hash] = j;

}



console.log('Done. No collisions below 10000.');



for (let j=1; j <11; j++)

  console.log(j, h(j));

edited Nov 13 '18 at 6:16

answered Nov 13 '18 at 3:09

גלעד ברקן

12.3k21439

add a comment |

Here's a hash function that seems to do what you are asking for :) As a bonus, it offers no collisions til 100,000.

function h(n){

  let s = [

    '0101000', '1011010', '0011111',

    '1100001', '1100101', '1011001',

    '1110011', '1010101', '1000111',

    '0001100', '1001000'].map(x => parseInt(x, 2));

    

  let m = parseInt('101', 2);

  

  s = s.map(x => {

    n ^= m;

    m <<= 1;

    return (x ^ n) % 52;

  });



  return s.map(x =>

    String.fromCharCode(x > 25 ? 71 + x : 65 + x)

  ).join('');

}



const s = {};



for (let j=1; j <=10000; j++){

  let hash = h(j);

  

  if (s[hash])

    console.log('Collision! ' + j + ' <-> ' + s[hash]);

    

  s[hash] = j;

}



console.log('Done. No collisions below 10000.');



for (let j=1; j <11; j++)

  console.log(j, h(j));

edited Nov 13 '18 at 6:16

answered Nov 13 '18 at 3:09

גלעד ברקן

12.3k21439

Here's a hash function that seems to do what you are asking for :) As a bonus, it offers no collisions til 100,000.

function h(n){

  let s = [

    '0101000', '1011010', '0011111',

    '1100001', '1100101', '1011001',

    '1110011', '1010101', '1000111',

    '0001100', '1001000'].map(x => parseInt(x, 2));

    

  let m = parseInt('101', 2);

  

  s = s.map(x => {

    n ^= m;

    m <<= 1;

    return (x ^ n) % 52;

  });



  return s.map(x =>

    String.fromCharCode(x > 25 ? 71 + x : 65 + x)

  ).join('');

}



const s = {};



for (let j=1; j <=10000; j++){

  let hash = h(j);

  

  if (s[hash])

    console.log('Collision! ' + j + ' <-> ' + s[hash]);

    

  s[hash] = j;

}



console.log('Done. No collisions below 10000.');



for (let j=1; j <11; j++)

  console.log(j, h(j));

function h(n){

  let s = [

    '0101000', '1011010', '0011111',

    '1100001', '1100101', '1011001',

    '1110011', '1010101', '1000111',

    '0001100', '1001000'].map(x => parseInt(x, 2));

    

  let m = parseInt('101', 2);

  

  s = s.map(x => {

    n ^= m;

    m <<= 1;

    return (x ^ n) % 52;

  });



  return s.map(x =>

    String.fromCharCode(x > 25 ? 71 + x : 65 + x)

  ).join('');

}



const s = {};



for (let j=1; j <=10000; j++){

  let hash = h(j);

  

  if (s[hash])

    console.log('Collision! ' + j + ' <-> ' + s[hash]);

    

  s[hash] = j;

}



console.log('Done. No collisions below 10000.');



for (let j=1; j <11; j++)

  console.log(j, h(j));

function h(n){

  let s = [

    '0101000', '1011010', '0011111',

    '1100001', '1100101', '1011001',

    '1110011', '1010101', '1000111',

    '0001100', '1001000'].map(x => parseInt(x, 2));

    

  let m = parseInt('101', 2);

  

  s = s.map(x => {

    n ^= m;

    m <<= 1;

    return (x ^ n) % 52;

  });



  return s.map(x =>

    String.fromCharCode(x > 25 ? 71 + x : 65 + x)

  ).join('');

}



const s = {};



for (let j=1; j <=10000; j++){

  let hash = h(j);

  

  if (s[hash])

    console.log('Collision! ' + j + ' <-> ' + s[hash]);

    

  s[hash] = j;

}



console.log('Done. No collisions below 10000.');



for (let j=1; j <11; j++)

  console.log(j, h(j));

edited Nov 13 '18 at 6:16

answered Nov 13 '18 at 3:09

גלעד ברקן

12.3k21439

edited Nov 13 '18 at 6:16

answered Nov 13 '18 at 3:09

גלעד ברקן

12.3k21439

answered Nov 13 '18 at 3:09

גלעד ברקן

12.3k21439

answered Nov 13 '18 at 3:09

גלעד ברקן

12.3k21439

add a comment |

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