bsv 2.1.1

A Bitcoin stdlib
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171

use crate::get_hash_digest;
use crate::hash::sha256d_digest::Sha256d;
use crate::BSVErrors;
use crate::DigestBytes;
use crate::PrivateKey;
use crate::RecoveryInfo;
use crate::Sha256r;
use crate::Signature;
use crate::SigningHash;
use crate::ECDSA;
use digest::generic_array::GenericArray;
use digest::{Digest, FixedOutput};
use ecdsa::hazmat::{rfc6979_generate_k, SignPrimitive};
use ecdsa::RecoveryId;
use elliptic_curve::ops::Reduce;
use k256::ecdsa::{recoverable, Signature as SecpSignature};
use k256::{FieldBytes, Scalar, SecretKey, U256};
use rand_core::OsRng;
use rand_core::RngCore;
use sha2::Sha256;

impl ECDSA {
    fn sign_preimage_deterministic_k<D>(priv_key: &SecretKey, digest: D, reverse_endian_k: bool) -> Result<(SecpSignature, Option<RecoveryId>), BSVErrors>
    where
        D: FixedOutput<OutputSize = digest::consts::U32> + digest::BlockInput + Clone + Default + digest::Reset + digest::Update + crate::ReversibleDigest,
    {
        let priv_scalar = priv_key.to_nonzero_scalar();
        let final_digest = digest.finalize_fixed();
        let k_digest = match reverse_endian_k {
            true => <Scalar as Reduce<U256>>::from_le_bytes_reduced(final_digest),
            false => <Scalar as Reduce<U256>>::from_be_bytes_reduced(final_digest),
        };

        let k = rfc6979_generate_k::<_, D>(&priv_scalar, &k_digest, &[]);

        let msg_scalar = <Scalar as Reduce<U256>>::from_be_bytes_reduced(final_digest);
        let (signature, recid) = priv_scalar.try_sign_prehashed(**k, msg_scalar)?;
        let recoverable_id = recid.ok_or_else(ecdsa::Error::new)?.try_into()?;
        let rec_sig = recoverable::Signature::new(&signature, recoverable_id)?;

        let id = rec_sig.recovery_id();
        let sig = SecpSignature::from(rec_sig);

        Ok((sig, Some(id.into())))
    }

    fn sign_digest_bytes_deterministic_k(priv_key: &SecretKey, digest_bytes: DigestBytes) -> Result<(SecpSignature, Option<RecoveryId>), BSVErrors> {
        let priv_scalar = priv_key.to_nonzero_scalar();
        let msg_scalar = <Scalar as Reduce<U256>>::from_be_bytes_reduced(digest_bytes);

        let k = rfc6979_generate_k::<_, Sha256r>(&priv_scalar, &msg_scalar, &[]);

        let (signature, recid) = priv_scalar.try_sign_prehashed(**k, msg_scalar)?;
        let recoverable_id = recid.ok_or_else(ecdsa::Error::new)?.try_into()?;
        let rec_sig = recoverable::Signature::new(&signature, recoverable_id)?;

        let id = rec_sig.recovery_id();
        let sig = SecpSignature::from(rec_sig);

        Ok((sig, Some(id.into())))
    }

    fn sign_preimage_random_k(priv_key: &SecretKey, digest: &[u8], reverse_endian_k: bool, hash_algo: SigningHash) -> Result<(SecpSignature, Option<RecoveryId>), ecdsa::Error> {
        let mut added_entropy = FieldBytes::default();
        let rng = &mut OsRng;
        rng.fill_bytes(&mut added_entropy);

        let priv_scalar = priv_key.to_nonzero_scalar();
        let k_digest = match reverse_endian_k {
            true => {
                let mut reversed_digest = digest.to_vec();
                reversed_digest.reverse();

                // TODO: Does this need to be from_be_slice ?
                let scalar_uint = U256::from_le_slice(&reversed_digest);
                Scalar::from_uint_reduced(scalar_uint)
            }
            false => Scalar::from_uint_reduced(U256::from_le_slice(digest)),
        };

        let k = match hash_algo {
            SigningHash::Sha256 => **rfc6979_generate_k::<_, Sha256>(&priv_scalar, &k_digest, &added_entropy),
            SigningHash::Sha256d => **rfc6979_generate_k::<_, Sha256d>(&priv_scalar, &k_digest, &added_entropy),
        };

        let msg_scalar = Scalar::from_uint_reduced(U256::from_le_slice(digest));
        priv_scalar.try_sign_prehashed(k, msg_scalar)
    }

    /**
     * Signs a message digest with a specific private and ephemeral key. I hope you know what you're doing!
     */
    pub(crate) fn sign_with_k_impl(private_key: &PrivateKey, ephemeral_key: &PrivateKey, preimage: &[u8], hash_algo: SigningHash) -> Result<Signature, BSVErrors> {
        let priv_scalar = *private_key.secret_key.to_nonzero_scalar();
        let k = *ephemeral_key.secret_key.to_nonzero_scalar();
        let digest = get_hash_digest(hash_algo, preimage);
        let digest_finalised = digest.finalize_fixed();
        let msg_scalar = <Scalar as Reduce<U256>>::from_be_bytes_reduced(digest_finalised);
        let (signature, recid) = priv_scalar.try_sign_prehashed(k, msg_scalar)?;
        let recoverable_id = recid.ok_or_else(ecdsa::Error::new)?.try_into()?;
        let rec_sig = recoverable::Signature::new(&signature, recoverable_id)?;
        let recovery: Option<RecoveryId> = Some(rec_sig.recovery_id().into());
        let sig = SecpSignature::from(rec_sig);
        Ok(Signature {
            sig,
            recovery: recovery.map(|x| RecoveryInfo::new(x.is_y_odd(), x.is_x_reduced(), private_key.is_pub_key_compressed)),
        })
    }

    /**
     * Signs the preimage hash digest directly. I hope you know what you're doing!
     */
    pub(crate) fn sign_digest_with_deterministic_k_impl(private_key: &PrivateKey, digest: &DigestBytes) -> Result<Signature, BSVErrors> {
        let (sig, recovery) = ECDSA::sign_digest_bytes_deterministic_k(&private_key.secret_key, *digest)?;

        Ok(Signature {
            sig,
            recovery: recovery.map(|x| RecoveryInfo::new(x.is_y_odd(), x.is_x_reduced(), private_key.is_pub_key_compressed)),
        })
    }

    /**
     * Hashes the preimage with the specified Hashing algorithm and then signs the specified message.
     * Secp256k1 signature inputs must be 32 bytes in length - SigningAlgo will output a 32 byte buffer.
     * HASH+HMAC can be reversed for K generation if necessary.
     */
    pub(crate) fn sign_with_deterministic_k_impl(private_key: &PrivateKey, preimage: &[u8], hash_algo: SigningHash, reverse_k: bool) -> Result<Signature, BSVErrors> {
        let digest = get_hash_digest(hash_algo, preimage);

        let (sig, recovery) = ECDSA::sign_preimage_deterministic_k(&private_key.secret_key, digest, reverse_k)?;

        Ok(Signature {
            sig,
            recovery: recovery.map(|x| RecoveryInfo::new(x.is_y_odd(), x.is_x_reduced(), private_key.is_pub_key_compressed)),
        })
    }

    /**
     * Hashes the preimage with the specified Hashing algorithm and then signs the specified message.
     * Secp256k1 signature inputs must be 32 bytes in length - SigningAlgo will output a 32 byte buffer.
     * HASH+HMAC can be reversed for K generation if necessary.
     */
    pub(crate) fn sign_with_random_k_impl(private_key: &PrivateKey, preimage: &[u8], hash_algo: SigningHash, reverse_k: bool) -> Result<Signature, BSVErrors> {
        let digest = get_hash_digest(hash_algo, preimage);

        let (sig, recovery) = ECDSA::sign_preimage_random_k(&private_key.secret_key, digest.finalize().as_slice(), reverse_k, hash_algo)?;

        Ok(Signature {
            sig,
            recovery: recovery.map(|x| RecoveryInfo::new(x.is_y_odd(), x.is_x_reduced(), private_key.is_pub_key_compressed)),
        })
    }
}

impl ECDSA {
    pub fn sign_with_random_k(private_key: &PrivateKey, preimage: &[u8], hash_algo: SigningHash, reverse_k: bool) -> Result<Signature, BSVErrors> {
        ECDSA::sign_with_random_k_impl(private_key, preimage, hash_algo, reverse_k)
    }

    pub fn sign_with_deterministic_k(private_key: &PrivateKey, preimage: &[u8], hash_algo: SigningHash, reverse_k: bool) -> Result<Signature, BSVErrors> {
        ECDSA::sign_with_deterministic_k_impl(private_key, preimage, hash_algo, reverse_k)
    }

    pub fn sign_with_k(private_key: &PrivateKey, ephemeral_key: &PrivateKey, preimage: &[u8], hash_algo: SigningHash) -> Result<Signature, BSVErrors> {
        ECDSA::sign_with_k_impl(private_key, ephemeral_key, preimage, hash_algo)
    }

    pub fn sign_digest_with_deterministic_k(private_key: &PrivateKey, digest: &[u8]) -> Result<Signature, BSVErrors> {
        ECDSA::sign_digest_with_deterministic_k_impl(private_key, GenericArray::from_slice(digest))
    }
}