mithril_common/crypto_helper/cardano/
codec.rs

1//! Module to provide functions to (de)serialise JSON data structures as used in Shelley,
2//! which have the following format:
3//! ```json
4//! {
5//!      "type": <NAME OF SERIALISED STRUCTURE>,
6//!      "description": <DESCRIPTION OF SERIALISED STRUCTURE>,
7//!      "cborHex": <CBOR HEX REPRESENTATION OF SERIALISED STRUCTURE>
8//!  }
9//! ```
10//!
11//! The trait `SerDeShelleyFileFormat` can be implemented for any structure that implements
12//! `Serialize` and `Deserialize`.
13
14use anyhow::{anyhow, Context};
15use hex::FromHex;
16use kes_summed_ed25519::kes::Sum6Kes;
17use kes_summed_ed25519::traits::KesSk;
18use serde::de::DeserializeOwned;
19use serde::{Deserialize, Serialize};
20use serde_with::{As, Bytes};
21use std::fs;
22use std::io::Write;
23use std::path::Path;
24use thiserror::Error;
25
26use crate::StdError;
27
28/// We need to create this struct because the design of Sum6Kes takes
29/// a reference to a mutable pointer. It is therefore not possible to
30/// implement Ser/Deser using serde.
31// We need this helper structure, because we are currently getting the key
32// from a file, instead of directly consuming a buffer.
33// todo: create the KES key directly from a buffer instead of deserialising from disk
34#[derive(Clone, Serialize, Deserialize)]
35pub struct Sum6KesBytes(#[serde(with = "As::<Bytes>")] pub [u8; 612]);
36
37/// Parse error
38#[derive(Error, Debug)]
39#[error("Codec parse error")]
40pub struct CodecParseError(#[source] StdError);
41
42/// Fields for a shelley formatted file (holds for vkeys, skeys or certs)
43#[derive(Clone, Debug, Default, Serialize, Deserialize)]
44struct ShelleyFileFormat {
45    #[serde(rename = "type")]
46    file_type: String,
47    description: String,
48    #[serde(rename = "cborHex")]
49    cbor_hex: String,
50}
51
52/// Trait that allows any structure that implements Serialize and DeserializeOwned to
53/// be serialized and deserialized following the Shelly json format.
54pub trait SerDeShelleyFileFormat: Serialize + DeserializeOwned {
55    /// The type of Cardano key
56    const TYPE: &'static str;
57
58    /// The description of the Cardano key
59    const DESCRIPTION: &'static str;
60
61    /// Deserialize a type `T: Serialize + DeserializeOwned` from file following Cardano
62    /// Shelley file format.
63    fn from_file<P: AsRef<Path>>(path: P) -> Result<Self, CodecParseError> {
64        let data = fs::read_to_string(path)
65            .with_context(|| "SerDeShelleyFileFormat can not read data from file {}")
66            .map_err(|e| CodecParseError(anyhow!(e)))?;
67        let file: ShelleyFileFormat = serde_json::from_str(&data)
68            .with_context(|| "SerDeShelleyFileFormat can not unserialize json data")
69            .map_err(|e| CodecParseError(anyhow!(e)))?;
70        let hex_vector = Vec::from_hex(file.cbor_hex)
71            .with_context(|| "SerDeShelleyFileFormat can not unserialize hex data")
72            .map_err(|e| CodecParseError(anyhow!(e)))?;
73        let mut cursor = std::io::Cursor::new(&hex_vector);
74        let a: Self = ciborium::de::from_reader(&mut cursor)
75            .with_context(|| "SerDeShelleyFileFormat can not unserialize cbor data")
76            .map_err(|e| CodecParseError(anyhow!(e)))?;
77
78        Ok(a)
79    }
80
81    /// Serialize a type `T: Serialize + DeserializeOwned` to file following Cardano
82    /// Shelley file format.
83    fn to_file<P: AsRef<Path>>(&self, path: P) -> Result<(), CodecParseError> {
84        let mut cursor = std::io::Cursor::new(Vec::new());
85        ciborium::ser::into_writer(&self, &mut cursor)
86            .with_context(|| "SerDeShelleyFileFormat can not serialize data to cbor")
87            .map_err(|e| CodecParseError(anyhow!(e)))?;
88        let cbor_string = hex::encode(cursor.into_inner());
89
90        let file_format = ShelleyFileFormat {
91            file_type: Self::TYPE.to_string(),
92            description: Self::DESCRIPTION.to_string(),
93            cbor_hex: cbor_string,
94        };
95
96        let mut file = fs::File::create(path)
97            .with_context(|| "SerDeShelleyFileFormat can not create file")
98            .map_err(|e| CodecParseError(anyhow!(e)))?;
99        let json_str = serde_json::to_string(&file_format)
100            .with_context(|| "SerDeShelleyFileFormat can not serialize data to json")
101            .map_err(|e| CodecParseError(anyhow!(e)))?;
102
103        write!(file, "{json_str}")
104            .with_context(|| "SerDeShelleyFileFormat can not write data to file")
105            .map_err(|e| CodecParseError(anyhow!(e)))?;
106        Ok(())
107    }
108}
109
110impl SerDeShelleyFileFormat for Sum6KesBytes {
111    const TYPE: &'static str = "KesSigningKey_ed25519_kes_2^6";
112    const DESCRIPTION: &'static str = "KES Signing Key";
113
114    /// Deserialize a Cardano key from file. Cardano KES key Shelley format does not
115    /// contain the period (it is always zero). Therefore we need to include it in the
116    /// deserialisation.
117    fn from_file<P: AsRef<Path>>(path: P) -> Result<Self, CodecParseError> {
118        let data = fs::read_to_string(path)
119            .with_context(|| "Sum6KesBytes can not read data from file")
120            .map_err(|e| CodecParseError(anyhow!(e)))?;
121        let file: ShelleyFileFormat = serde_json::from_str(&data)
122            .with_context(|| "Sum6KesBytes can not unserialize json data")
123            .map_err(|e| CodecParseError(anyhow!(e)))?;
124        let mut hex_vector = Vec::from_hex(file.cbor_hex)
125            .with_context(|| "Sum6KesBytes can not unserialize hex data")
126            .map_err(|e| CodecParseError(anyhow!(e)))?;
127
128        // We check whether the serialisation was performed by the haskell library or the rust library
129        if (hex_vector[2] & 4u8) == 0 {
130            // First we need to change the cbor format to notify about the extra 4 bytes:
131            hex_vector[2] |= 4u8;
132            // Then we append the bytes representing the period = 0
133            hex_vector.extend_from_slice(&[0u8; 4]);
134        }
135
136        let mut cursor = std::io::Cursor::new(&hex_vector);
137        let a: Self = ciborium::from_reader(&mut cursor)
138            .with_context(|| "Sum6KesBytes can not unserialize cbor data")
139            .map_err(|e| CodecParseError(anyhow!(e)))?;
140        Ok(a)
141    }
142}
143
144impl<'a> TryFrom<&'a mut Sum6KesBytes> for Sum6Kes<'a> {
145    type Error = CodecParseError;
146
147    fn try_from(value: &'a mut Sum6KesBytes) -> Result<Self, Self::Error> {
148        Self::from_bytes(&mut value.0).map_err(|e| CodecParseError(anyhow!(format!("{e:?}"))))
149    }
150}
151
152#[cfg(test)]
153mod test {
154    use super::*;
155    use crate::test_utils::TempDir;
156
157    #[test]
158    fn compat_with_shelly_format() {
159        let temp_dir = TempDir::create("crypto_helper", "compat_with_shelly_format");
160        let sk_dir = temp_dir.join("dummy.skey");
161        let cbor_string = "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".to_string();
162
163        let file_format = ShelleyFileFormat {
164            file_type: Sum6KesBytes::TYPE.to_string(),
165            description: Sum6KesBytes::DESCRIPTION.to_string(),
166            cbor_hex: cbor_string,
167        };
168
169        let mut file =
170            fs::File::create(sk_dir.clone()).expect("Unexpected error with file creation.");
171        let json_str =
172            serde_json::to_string(&file_format).expect("Unexpected error with serialisation.");
173
174        write!(file, "{json_str}").expect("Unexpected error writing to file.");
175
176        let mut kes_sk_bytes =
177            Sum6KesBytes::from_file(&sk_dir).expect("Failure parsing Shelley file format.");
178
179        assert!(Sum6Kes::try_from(&mut kes_sk_bytes).is_ok());
180    }
181}
mithril_common/crypto_helper/cardano/codec.rs

mithril_common/crypto_helper/cardano/
codec.rs
