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Implemented Checksum
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@qkniep
qkniep committed Apr 29, 2021
1 parent 3ccc8ae commit b97384d
Showing 1 changed file with 78 additions and 49 deletions.
127 changes: 78 additions & 49 deletions src/wots.rs
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Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
use blake2_rfc::blake2b::{Blake2b, blake2b};
use hex;
use blake2_rfc::blake2b::{blake2b, Blake2b};
use getrandom;

use hex;

/// # W-OTS Keypair
/// This struct contains the W-OTS Keypair, including:
Expand Down Expand Up @@ -32,25 +31,24 @@ pub struct WotsSignature {
impl Wots {
/// # Signature Function
/// This function will let you sign an input hexadecimal string of up to 256bits.
pub fn sign (&self, input: String) -> WotsSignature {
pub fn sign(&self, input: String) -> WotsSignature {
// Create Empty Signature and Cycle Vector
let mut signature: Vec<String> = vec![];
let mut sig_cycles: Vec<usize> = vec![];

// Input Formatting
let input_uppercase = input.to_ascii_uppercase().clone();
let input_vector = input_uppercase.clone().into_bytes();

// Get Length of String and Assert It Is Not Longer Than PK
let length: usize = input_vector.len();
assert!(self.pk.len() >= length);

// The Loop Itself
for i in 0..length {

// Turn Into Byte From Vector
let byte = input_vector[i];

// HEX: 0-9 (0-9)
if byte >= 48 && byte <= 57 {
let x: u8 = byte - 48u8;
Expand All @@ -65,12 +63,28 @@ impl Wots {
else if byte >= 97 && byte <= 102 {
let x: u8 = byte - 87u8;
sig_cycles.push(x as usize);
}
else {
} else {
panic!("The Input Is Not Supported Because Of Invalid Characters.")
}
// TODO: Remove Clone
let sig: String = blake_hash(self.sk[i].clone(),sig_cycles[i]);
let sig: String = blake_hash(self.sk[i].clone(), sig_cycles[i]);
signature.push(sig);
}

// Calculate Checksum
let mut checksum = 0;
for i in 0..length {
checksum += self.w - 1 - sig_cycles[i];
}

// Convert Checksum to base w and sign as well
let log_2_w = f64::log2(self.w as f64).round() as usize;
let max_cksum_value = f64::log2((length * (self.w - 1)) as f64).round();
let len_2 = f64::floor(max_cksum_value / log_2_w as f64) as usize + 1;
checksum = checksum << (8 - ((len_2 * log_2_w) % 8));
for i in 0..len_2 {
let symbol = (checksum >> (log_2_w * (len_2 - 1 - i))) % self.w;
let sig: String = blake_hash(self.sk[length + i].clone(), symbol);
signature.push(sig);
}

Expand Down Expand Up @@ -101,10 +115,10 @@ impl Wots {
if digest > 64usize || digest == 0usize {
panic!("Digest Provided Is Either Too Small Or Too Large. It should be between 1 and 64 bytes.");
}

// Get Length Of Public Key
let pk_length = self.pk.len();

// Create Blake2B Hashing Context
let mut pk_hash = Blake2b::new(digest);

Expand All @@ -113,7 +127,7 @@ impl Wots {
let s = self.pk[i].clone();
pk_hash.update(&hex::decode(s).unwrap());
}

// Finalize Result As Blake2bResult and then convert into bytes which is encoded in hexadecimal
let result = pk_hash.finalize();
let output: String = hex::encode_upper(result.as_bytes());
Expand All @@ -129,14 +143,14 @@ impl WotsSignature {
// Input Formatting
let input_uppercase = input.to_ascii_uppercase().clone();
let input_vector = input_uppercase.clone().into_bytes();

// Get Length of String and Assert It Is Not Longer Than PK
let length: usize = input_vector.len();

for i in 0..length {
for i in 0..length {
// Turn Into Byte From Vector
let byte = input_vector[i];

// HEX: 0-9 (0-9)
if byte >= 48 && byte <= 57 {
let x: u8 = byte - 48u8;
Expand All @@ -151,37 +165,54 @@ impl WotsSignature {
else if byte >= 97 && byte <= 102 {
let x: u8 = byte - 87u8;
sig_cycles.push(x as usize);
}
else {
} else {
panic!("The Input Is Not Supported Because Of Invalid Characters.")
}
}
return sig_cycles;
}
/// # Verification of Signature
/// This function allows you to verify the signature against the public key.
pub fn verify (&self) -> bool {
pub fn verify(&self) -> bool {
let signature_cycles: Vec<usize> = self.cycle(self.input.clone());
let length: usize = signature_cycles.len();

for i in 0..length {
let cycle: usize = 16usize - signature_cycles[i];
let blake: String = blake_hash(self.signature[i].clone(),cycle);
assert_eq!(self.pk[i],blake)
let blake: String = blake_hash(self.signature[i].clone(), cycle);
assert_eq!(self.pk[i], blake)
}

// Calculate Checksum
let mut checksum = 0;
for i in 0..length {
checksum += 16 - 1 - signature_cycles[i];
}

// Convert Checksum to base w and compare with PK as well
let log_2_w = f64::log2(16 as f64).round() as usize;
let max_cksum_value = f64::log2((length * (16 - 1)) as f64).round();
let len_2 = f64::floor(max_cksum_value / log_2_w as f64) as usize + 1;
checksum = checksum << (8 - ((len_2 * log_2_w) % 8));
for i in 0..len_2 {
let cycle: usize = (checksum >> (log_2_w * (len_2 - 1 - i))) % 16;
let blake: String = blake_hash(self.signature[length + i].clone(), 16 - cycle);
assert_eq!(self.pk[length + i], blake);
}

return true;
}
/// # Verification of Public Key Hash
/// This function allows you to verify the hash of the public key. Only useful in a small amount of situations.
pub fn verify_public_key_hash (&self, mut input: String) -> bool {
pub fn verify_public_key_hash(&self, mut input: String) -> bool {
input = input.to_uppercase();

// Get Digest By Dividing The Hexadecimal Representation By 2
let digest = input.len() / 2usize;

// Get Length Of Public Key
let pk_length = self.pk.len();

// Create Blake2B Hashing Context
let mut pk_hash = Blake2b::new(digest);

Expand All @@ -190,16 +221,15 @@ impl WotsSignature {
let s = self.pk[i].clone();
pk_hash.update(&hex::decode(s).unwrap());
}

// Finalize Result As Blake2bResult and then convert into bytes which is encoded in hexadecimal
let result = pk_hash.finalize();
let output: String = hex::encode_upper(result.as_bytes());

if input == output {
return true
}
else {
return false
return true;
} else {
return false;
}
}
}
Expand All @@ -215,22 +245,18 @@ fn os_32() -> Result<[u8; 32], getrandom::Error> {
// s: Hexadecimal String To Be Hashed
// w: Cycles of Hash Iterations To Be Performed
#[allow(dead_code)]
fn blake_hash(s: String, w:usize) -> String {
fn blake_hash(s: String, w: usize) -> String {
let mut _is_generation: bool = false;
let mut _is_signing: bool = false;



if w == 0usize {
return s;
}
else if w == 16usize {
} else if w == 16usize {
// Does Not Mean Anything As You Can Do This From The Secret Key Provided (0000)
_is_generation = true;
}
else if w > 16usize {
} else if w > 16usize {
panic!("This Amount of Cycles is Not Supported")
}
else {
} else {
_is_signing = true;
}

Expand All @@ -239,15 +265,15 @@ fn blake_hash(s: String, w:usize) -> String {
// Turn Bytes Into An Array of Bytes
let mut _blake = blake2b(32, &[], bytes.as_slice());
let mut blake = _blake.as_bytes();

// Cycles (w - 1) because the hex is decoded into a Vector and then hashed once before the loop
let cycles = w - 1usize;

// If A Single Hash is Performed and the cycles counter reaches 0, then return the value
if cycles == 0usize {
return hex::encode_upper(&blake);
}

// MAIN: The Loop Cycle
for _i in 0..cycles {
_blake = blake2b(32, &[], &blake);
Expand All @@ -265,29 +291,32 @@ fn blake_hash(s: String, w:usize) -> String {
pub fn generate_wots() -> Wots {
let w: usize = 16; // Default Winternitz Parameter (signing 4 bits at a time)
let n: usize = 32; // Default Digest Size in Bytes (256bits)

// Create Secret Key and Public Key Pair
let mut sk: Vec<String> = vec![];
let mut pk: Vec<String> = vec![];


for _i in 0..64 {
let log_2_w = f64::log2(16 as f64).round() as usize;
let max_cksum_value = f64::log2((64 * (16 - 1)) as f64).round();
let len_2 = f64::floor(max_cksum_value / log_2_w as f64) as usize + 1;

for _i in 0..64 + len_2 {
// Generate Secret Key and Encode In Hexadecimal as a String
let secret: [u8;32] = os_32().unwrap();
let secret: [u8; 32] = os_32().unwrap();
let secret_hex: String = hex::encode_upper(secret);

sk.push(secret_hex.clone());

// Generate Public Key
let public = blake_hash(secret_hex, w);

pk.push(public)
}
let output = Wots {
w: w,
w: w,
n: n,
pk: pk,
sk: sk,
};
return output;
}
}

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