latticearc 0.7.1

#![deny(unsafe_code)]
#![deny(missing_docs)]
#![deny(clippy::unwrap_used)]
#![deny(clippy::panic)]

//! Serialization utilities for cryptographic types.
//!
//! Provides JSON serialization for encrypted data, signed data, and key pairs
//! using Base64 encoding for binary fields.

use base64::{Engine, engine::general_purpose::STANDARD as BASE64_ENGINE};
use serde::{Deserialize, Serialize};
use subtle::ConstantTimeEq;
use zeroize::Zeroize;

use crate::unified_api::crypto_types::{EncryptedOutput, EncryptionScheme, HybridComponents};
use crate::unified_api::{
    error::{CoreError, Result},
    types::{KeyPair, SignedData},
};

/// Serializable form of signed data
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SerializableSignedData {
    /// Base64-encoded original data
    pub data: String,
    /// Signature metadata
    pub metadata: SerializableSignedMetadata,
    /// Signature scheme identifier
    pub scheme: String,
    /// Timestamp of signing
    pub timestamp: u64,
}

/// Serializable signed data metadata
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SerializableSignedMetadata {
    /// Base64-encoded signature
    pub signature: String,
    /// Signature algorithm
    pub signature_algorithm: String,
    /// Base64-encoded public key
    pub public_key: String,
    /// Key identifier (optional)
    pub key_id: Option<String>,
}

/// Serializable form of a key pair.
///
/// `SerializableKeyPair` deliberately does NOT implement `Clone`. Duplicating
/// a serialized keypair would transiently double the number of base64-encoded
/// private-key copies in memory. When two independent instances are genuinely
/// needed (e.g., for serialization roundtrip tests), construct them separately
/// from the same source key via [`SerializableKeyPair::from`].
#[derive(Serialize, Deserialize)]
pub struct SerializableKeyPair {
    /// Base64-encoded public key.
    public_key: String,
    /// Base64-encoded private key.
    private_key: String,
}

impl SerializableKeyPair {
    /// Create a new `SerializableKeyPair` from base64-encoded key strings.
    #[must_use]
    pub fn new(public_key: String, private_key: String) -> Self {
        Self { public_key, private_key }
    }

    /// Returns the base64-encoded public key.
    #[must_use]
    pub fn public_key(&self) -> &str {
        &self.public_key
    }

    /// Returns the base64-encoded private key.
    #[must_use]
    pub fn private_key(&self) -> &str {
        &self.private_key
    }
}

impl std::fmt::Debug for SerializableKeyPair {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("SerializableKeyPair")
            .field("public_key", &self.public_key)
            .field("private_key", &"[REDACTED]")
            .finish()
    }
}

impl ConstantTimeEq for SerializableKeyPair {
    fn ct_eq(&self, other: &Self) -> subtle::Choice {
        self.private_key.as_bytes().ct_eq(other.private_key.as_bytes())
    }
}

impl Drop for SerializableKeyPair {
    fn drop(&mut self) {
        // Zeroize private key string bytes before deallocation to prevent
        // sensitive key material from lingering in freed heap memory.
        self.private_key.zeroize();
    }
}

impl From<&SignedData> for SerializableSignedData {
    fn from(signed: &SignedData) -> Self {
        Self {
            data: BASE64_ENGINE.encode(&signed.data),
            metadata: SerializableSignedMetadata {
                signature: BASE64_ENGINE.encode(&signed.metadata.signature),
                signature_algorithm: signed.metadata.signature_algorithm.clone(),
                public_key: BASE64_ENGINE.encode(&signed.metadata.public_key),
                key_id: signed.metadata.key_id.clone(),
            },
            scheme: signed.scheme.clone(),
            timestamp: signed.timestamp,
        }
    }
}

impl TryFrom<SerializableSignedData> for SignedData {
    type Error = CoreError;

    fn try_from(serializable: SerializableSignedData) -> Result<Self> {
        let data = BASE64_ENGINE
            .decode(&serializable.data)
            .map_err(|e| CoreError::SerializationError(e.to_string()))?;

        let signature = BASE64_ENGINE
            .decode(&serializable.metadata.signature)
            .map_err(|e| CoreError::SerializationError(e.to_string()))?;

        let public_key = BASE64_ENGINE
            .decode(&serializable.metadata.public_key)
            .map_err(|e| CoreError::SerializationError(e.to_string()))?;

        Ok(SignedData {
            data,
            metadata: crate::types::SignedMetadata {
                signature,
                signature_algorithm: serializable.metadata.signature_algorithm,
                public_key,
                key_id: serializable.metadata.key_id,
            },
            scheme: serializable.scheme,
            timestamp: serializable.timestamp,
        })
    }
}

impl From<&KeyPair> for SerializableKeyPair {
    fn from(keypair: &KeyPair) -> Self {
        Self {
            public_key: BASE64_ENGINE.encode(keypair.public_key().as_slice()),
            private_key: BASE64_ENGINE.encode(keypair.private_key().as_slice()),
        }
    }
}

impl TryFrom<SerializableKeyPair> for KeyPair {
    type Error = CoreError;

    fn try_from(serializable: SerializableKeyPair) -> Result<Self> {
        let public_key_bytes = BASE64_ENGINE
            .decode(&serializable.public_key)
            .map_err(|e| CoreError::SerializationError(e.to_string()))?;

        let private_key_bytes = BASE64_ENGINE
            .decode(&serializable.private_key)
            .map_err(|e| CoreError::SerializationError(e.to_string()))?;

        let public_key = crate::types::PublicKey::new(public_key_bytes);
        let private_key = crate::types::PrivateKey::new(private_key_bytes);

        Ok(KeyPair::new(public_key, private_key))
    }
}

/// Serializes signed data to a JSON string.
///
/// # Errors
///
/// Returns an error if JSON serialization fails.
pub fn serialize_signed_data(signed: &SignedData) -> Result<String> {
    let serializable = SerializableSignedData::from(signed);
    serde_json::to_string(&serializable).map_err(|e| CoreError::SerializationError(e.to_string()))
}

/// Deserializes signed data from a JSON string.
///
/// # Errors
///
/// Returns an error if:
/// - JSON parsing fails
/// - Base64 decoding of the data, signature, or public key fails
pub fn deserialize_signed_data(data: &str) -> Result<SignedData> {
    let serializable: SerializableSignedData =
        serde_json::from_str(data).map_err(|e| CoreError::SerializationError(e.to_string()))?;
    serializable.try_into()
}

/// Serializes a keypair to a JSON string.
///
/// # Errors
///
/// Returns an error if JSON serialization fails.
pub fn serialize_keypair(keypair: &KeyPair) -> Result<String> {
    let serializable = SerializableKeyPair::from(keypair);
    serde_json::to_string(&serializable).map_err(|e| CoreError::SerializationError(e.to_string()))
}

/// Deserializes a keypair from a JSON string.
///
/// # Errors
///
/// Returns an error if:
/// - JSON parsing fails
/// - Base64 decoding of the public key or private key fails
pub fn deserialize_keypair(data: &str) -> Result<KeyPair> {
    let serializable: SerializableKeyPair =
        serde_json::from_str(data).map_err(|e| CoreError::SerializationError(e.to_string()))?;
    serializable.try_into()
}

// ============================================================================
// EncryptedOutput serialization (with hybrid support)
// ============================================================================

/// Serializable form of `EncryptedOutput`.
///
/// Includes hybrid component support (KEM ciphertext + ephemeral ECDH key).
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SerializableEncryptedOutput {
    /// Format version (`2` for `EncryptedOutput`)
    pub version: u8,
    /// Encryption scheme identifier (e.g., `"aes-256-gcm"`)
    pub scheme: String,
    /// Base64-encoded ciphertext
    pub ciphertext: String,
    /// Base64-encoded AEAD nonce (12 bytes)
    pub nonce: String,
    /// Base64-encoded AEAD authentication tag (16 bytes)
    pub tag: String,
    /// Hybrid components (present only for hybrid schemes)
    #[serde(skip_serializing_if = "Option::is_none")]
    pub hybrid_data: Option<SerializableHybridComponents>,
    /// Unix timestamp when encryption was performed
    pub timestamp: u64,
    /// Optional key identifier for key management
    #[serde(skip_serializing_if = "Option::is_none")]
    pub key_id: Option<String>,
}

/// Serializable hybrid components (KEM ciphertext + ephemeral ECDH key).
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SerializableHybridComponents {
    /// Base64-encoded ML-KEM ciphertext (1088 bytes for ML-KEM-768)
    pub ml_kem_ciphertext: String,
    /// Base64-encoded X25519 ephemeral public key (32 bytes)
    pub ecdh_ephemeral_pk: String,
}

impl From<&EncryptedOutput> for SerializableEncryptedOutput {
    fn from(output: &EncryptedOutput) -> Self {
        Self {
            version: 2,
            scheme: output.scheme().as_str().to_string(),
            ciphertext: BASE64_ENGINE.encode(output.ciphertext()),
            nonce: BASE64_ENGINE.encode(output.nonce()),
            tag: BASE64_ENGINE.encode(output.tag()),
            hybrid_data: output.hybrid_data().map(|hd| SerializableHybridComponents {
                ml_kem_ciphertext: BASE64_ENGINE.encode(hd.ml_kem_ciphertext()),
                ecdh_ephemeral_pk: BASE64_ENGINE.encode(hd.ecdh_ephemeral_pk()),
            }),
            timestamp: output.timestamp(),
            key_id: output.key_id().map(str::to_owned),
        }
    }
}

impl TryFrom<SerializableEncryptedOutput> for EncryptedOutput {
    type Error = CoreError;

    fn try_from(ser: SerializableEncryptedOutput) -> Result<Self> {
        // Defense-in-depth: reject excessively large serialized payloads before
        // base64 decode.
        const MAX_SERIALIZED_SIZE: usize = 10 * 1024 * 1024; // 10 MiB
        if ser.ciphertext.len() > MAX_SERIALIZED_SIZE {
            return Err(CoreError::SerializationError(format!(
                "Serialized ciphertext size {} exceeds maximum of {} bytes",
                ser.ciphertext.len(),
                MAX_SERIALIZED_SIZE
            )));
        }

        let scheme = EncryptionScheme::parse_str(&ser.scheme).ok_or_else(|| {
            CoreError::SerializationError(format!("Unknown encryption scheme: '{}'", ser.scheme))
        })?;

        let ciphertext = BASE64_ENGINE.decode(&ser.ciphertext).map_err(|e| {
            CoreError::SerializationError(format!("Invalid ciphertext base64: {}", e))
        })?;

        let nonce = BASE64_ENGINE
            .decode(&ser.nonce)
            .map_err(|e| CoreError::SerializationError(format!("Invalid nonce base64: {}", e)))?;

        let tag = BASE64_ENGINE
            .decode(&ser.tag)
            .map_err(|e| CoreError::SerializationError(format!("Invalid tag base64: {}", e)))?;

        let hybrid_data = ser
            .hybrid_data
            .map(|hd| -> Result<HybridComponents> {
                let ml_kem_ciphertext =
                    BASE64_ENGINE.decode(&hd.ml_kem_ciphertext).map_err(|e| {
                        CoreError::SerializationError(format!(
                            "Invalid KEM ciphertext base64: {}",
                            e
                        ))
                    })?;
                let ecdh_ephemeral_pk =
                    BASE64_ENGINE.decode(&hd.ecdh_ephemeral_pk).map_err(|e| {
                        CoreError::SerializationError(format!(
                            "Invalid ECDH ephemeral PK base64: {}",
                            e
                        ))
                    })?;
                Ok(HybridComponents::new(ml_kem_ciphertext, ecdh_ephemeral_pk))
            })
            .transpose()?;

        Ok(EncryptedOutput::new(
            scheme,
            ciphertext,
            nonce,
            tag,
            hybrid_data,
            ser.timestamp,
            ser.key_id,
        ))
    }
}

/// Serializes `EncryptedOutput` to a JSON string.
///
/// This is the canonical serialization for data encrypted with the unified API.
/// It supports hybrid encryption components (ML-KEM ciphertext + X25519
/// ephemeral key).
///
/// # Errors
///
/// Returns an error if JSON serialization fails.
pub fn serialize_encrypted_output(output: &EncryptedOutput) -> Result<String> {
    let serializable = SerializableEncryptedOutput::from(output);
    serde_json::to_string(&serializable).map_err(|e| CoreError::SerializationError(e.to_string()))
}

/// Deserializes `EncryptedOutput` from a JSON string.
///
/// # Errors
///
/// Returns an error if:
/// - JSON parsing fails
/// - Base64 decoding of any binary field fails
/// - The scheme string is unrecognized
pub fn deserialize_encrypted_output(data: &str) -> Result<EncryptedOutput> {
    let serializable: SerializableEncryptedOutput =
        serde_json::from_str(data).map_err(|e| CoreError::SerializationError(e.to_string()))?;
    serializable.try_into()
}

#[cfg(test)]
#[allow(clippy::unwrap_used, clippy::expect_used, clippy::indexing_slicing)]
mod tests {
    use super::*;
    use crate::types::{CryptoPayload, PrivateKey, SignedMetadata};
    use crate::unified_api::crypto_types::{EncryptedOutput, EncryptionScheme, HybridComponents};

    fn make_signed_data() -> SignedData {
        CryptoPayload {
            data: vec![1, 2, 3, 4],
            metadata: SignedMetadata {
                signature: vec![0xBB; 64],
                signature_algorithm: "ML-DSA-65".to_string(),
                public_key: vec![0xCC; 32],
                key_id: Some("sig-key-001".to_string()),
            },
            scheme: "ML-DSA-65+Ed25519".to_string(),
            timestamp: 1700000002,
        }
    }

    fn make_keypair() -> KeyPair {
        KeyPair::new(crate::types::PublicKey::new(vec![1u8; 32]), PrivateKey::new(vec![2u8; 64]))
    }

    // --- SignedData serialization ---

    #[test]
    fn test_signed_data_roundtrip() {
        let original = make_signed_data();
        let json = serialize_signed_data(&original).unwrap();
        let deserialized = deserialize_signed_data(&json).unwrap();

        assert_eq!(original.data, deserialized.data);
        assert_eq!(original.metadata.signature, deserialized.metadata.signature);
        assert_eq!(
            original.metadata.signature_algorithm,
            deserialized.metadata.signature_algorithm
        );
        assert_eq!(original.metadata.public_key, deserialized.metadata.public_key);
        assert_eq!(original.metadata.key_id, deserialized.metadata.key_id);
        assert_eq!(original.scheme, deserialized.scheme);
        assert_eq!(original.timestamp, deserialized.timestamp);
    }

    #[test]
    fn test_signed_data_from_trait_succeeds() {
        let original = make_signed_data();
        let serializable = SerializableSignedData::from(&original);
        assert!(!serializable.data.is_empty());
        assert_eq!(serializable.metadata.signature_algorithm, "ML-DSA-65");
    }

    #[test]
    fn test_signed_data_try_from_invalid_base64_fails() {
        let bad = SerializableSignedData {
            data: "not-valid!!!".to_string(),
            metadata: SerializableSignedMetadata {
                signature: BASE64_ENGINE.encode(b"sig"),
                signature_algorithm: "test".to_string(),
                public_key: BASE64_ENGINE.encode(b"pk"),
                key_id: None,
            },
            scheme: "test".to_string(),
            timestamp: 0,
        };
        let result: std::result::Result<SignedData, _> = bad.try_into();
        assert!(result.is_err());
    }

    #[test]
    fn test_signed_data_try_from_invalid_signature_fails() {
        let bad = SerializableSignedData {
            data: BASE64_ENGINE.encode(b"data"),
            metadata: SerializableSignedMetadata {
                signature: "not-valid!!!".to_string(),
                signature_algorithm: "test".to_string(),
                public_key: BASE64_ENGINE.encode(b"pk"),
                key_id: None,
            },
            scheme: "test".to_string(),
            timestamp: 0,
        };
        let result: std::result::Result<SignedData, _> = bad.try_into();
        assert!(result.is_err());
    }

    #[test]
    fn test_signed_data_try_from_invalid_public_key_fails() {
        let bad = SerializableSignedData {
            data: BASE64_ENGINE.encode(b"data"),
            metadata: SerializableSignedMetadata {
                signature: BASE64_ENGINE.encode(b"sig"),
                signature_algorithm: "test".to_string(),
                public_key: "not-valid!!!".to_string(),
                key_id: None,
            },
            scheme: "test".to_string(),
            timestamp: 0,
        };
        let result: std::result::Result<SignedData, _> = bad.try_into();
        assert!(result.is_err());
    }

    #[test]
    fn test_deserialize_signed_data_invalid_json_fails() {
        let result = deserialize_signed_data("not json");
        assert!(result.is_err());
    }

    // --- KeyPair serialization ---

    #[test]
    fn test_keypair_roundtrip() {
        let original = make_keypair();
        let json = serialize_keypair(&original).unwrap();
        let deserialized = deserialize_keypair(&json).unwrap();

        assert_eq!(original.public_key(), deserialized.public_key());
        assert_eq!(original.private_key().as_slice(), deserialized.private_key().as_slice());
    }

    #[test]
    fn test_keypair_from_trait_succeeds() {
        let original = make_keypair();
        let serializable = SerializableKeyPair::from(&original);
        assert!(!serializable.public_key.is_empty());
        assert!(!serializable.private_key.is_empty());
    }

    #[test]
    fn test_keypair_try_from_invalid_public_key_fails() {
        let bad = SerializableKeyPair {
            public_key: "not-valid!!!".to_string(),
            private_key: BASE64_ENGINE.encode(b"secret"),
        };
        let result: std::result::Result<KeyPair, _> = bad.try_into();
        assert!(result.is_err());
    }

    #[test]
    fn test_keypair_try_from_invalid_private_key_fails() {
        let bad = SerializableKeyPair {
            public_key: BASE64_ENGINE.encode(b"public"),
            private_key: "not-valid!!!".to_string(),
        };
        let result: std::result::Result<KeyPair, _> = bad.try_into();
        assert!(result.is_err());
    }

    #[test]
    fn test_deserialize_keypair_invalid_json_fails() {
        let result = deserialize_keypair("not json");
        assert!(result.is_err());
    }

    // --- EncryptedOutput serialization ---

    fn make_encrypted_output_symmetric() -> EncryptedOutput {
        EncryptedOutput::new(
            EncryptionScheme::Aes256Gcm,
            vec![0xDE, 0xAD, 0xBE, 0xEF],
            vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12],
            vec![0xAA; 16],
            None,
            1_700_000_000,
            Some("key-001".to_string()),
        )
    }

    fn make_encrypted_output_hybrid() -> EncryptedOutput {
        EncryptedOutput::new(
            EncryptionScheme::HybridMlKem768Aes256Gcm,
            vec![0xBE, 0xEF, 0xCA, 0xFE],
            vec![0u8; 12],
            vec![0xBB; 16],
            Some(HybridComponents::new(vec![0xCC; 1088], vec![0xDD; 32])),
            1_700_000_001,
            None,
        )
    }

    #[test]
    fn test_encrypted_output_symmetric_roundtrip() {
        let original = make_encrypted_output_symmetric();
        let json = serialize_encrypted_output(&original).unwrap();
        let deserialized = deserialize_encrypted_output(&json).unwrap();

        assert_eq!(original.scheme(), deserialized.scheme());
        assert_eq!(original.ciphertext(), deserialized.ciphertext());
        assert_eq!(original.nonce(), deserialized.nonce());
        assert_eq!(original.tag(), deserialized.tag());
        assert!(deserialized.hybrid_data().is_none());
        assert_eq!(original.timestamp(), deserialized.timestamp());
        assert_eq!(original.key_id(), deserialized.key_id());
    }

    #[test]
    fn test_encrypted_output_hybrid_roundtrip() {
        let original = make_encrypted_output_hybrid();
        let json = serialize_encrypted_output(&original).unwrap();
        let deserialized = deserialize_encrypted_output(&json).unwrap();

        assert_eq!(original.scheme(), deserialized.scheme());
        assert_eq!(original.ciphertext(), deserialized.ciphertext());
        assert_eq!(original.nonce(), deserialized.nonce());
        assert_eq!(original.tag(), deserialized.tag());
        assert_eq!(original.timestamp(), deserialized.timestamp());
        assert_eq!(original.key_id(), deserialized.key_id());

        let orig_hd = original.hybrid_data().unwrap();
        let deser_hd = deserialized.hybrid_data().unwrap();
        assert_eq!(orig_hd.ml_kem_ciphertext(), deser_hd.ml_kem_ciphertext());
        assert_eq!(orig_hd.ecdh_ephemeral_pk(), deser_hd.ecdh_ephemeral_pk());
    }

    #[test]
    fn test_encrypted_output_version_field_succeeds() {
        let output = make_encrypted_output_symmetric();
        let json = serialize_encrypted_output(&output).unwrap();
        let raw: serde_json::Value = serde_json::from_str(&json).unwrap();
        assert_eq!(raw["version"], 2);
    }

    #[test]
    fn test_encrypted_output_scheme_as_string_succeeds() {
        let output = make_encrypted_output_hybrid();
        let json = serialize_encrypted_output(&output).unwrap();
        let raw: serde_json::Value = serde_json::from_str(&json).unwrap();
        assert_eq!(raw["scheme"], "hybrid-ml-kem-768-aes-256-gcm");
    }

    #[test]
    fn test_encrypted_output_hybrid_data_omitted_when_none_succeeds() {
        let output = make_encrypted_output_symmetric();
        let json = serialize_encrypted_output(&output).unwrap();
        let raw: serde_json::Value = serde_json::from_str(&json).unwrap();
        assert!(raw.get("hybrid_data").is_none());
    }

    #[test]
    fn test_encrypted_output_key_id_omitted_when_none_succeeds() {
        let output = make_encrypted_output_hybrid(); // key_id is None
        let json = serialize_encrypted_output(&output).unwrap();
        let raw: serde_json::Value = serde_json::from_str(&json).unwrap();
        assert!(raw.get("key_id").is_none());
    }

    #[test]
    fn test_encrypted_output_unknown_scheme_rejected_fails() {
        let json = r#"{"version":2,"scheme":"fake-999","ciphertext":"AAAA","nonce":"AAAA","tag":"AAAA","timestamp":0}"#;
        let result = deserialize_encrypted_output(json);
        assert!(result.is_err());
        let err = format!("{}", result.unwrap_err());
        assert!(err.contains("Unknown encryption scheme"));
    }

    #[test]
    fn test_encrypted_output_invalid_ciphertext_base64_fails() {
        let json = r#"{"version":2,"scheme":"aes-256-gcm","ciphertext":"not-valid!!!","nonce":"AAAA","tag":"AAAA","timestamp":0}"#;
        let result = deserialize_encrypted_output(json);
        assert!(result.is_err());
    }

    #[test]
    fn test_encrypted_output_invalid_hybrid_base64_fails() {
        let json = r#"{"version":2,"scheme":"hybrid-ml-kem-768-aes-256-gcm","ciphertext":"AAAA","nonce":"AAAA","tag":"AAAA","hybrid_data":{"ml_kem_ciphertext":"not-valid!!!","ecdh_ephemeral_pk":"AAAA"},"timestamp":0}"#;
        let result = deserialize_encrypted_output(json);
        assert!(result.is_err());
    }

    #[test]
    fn test_encrypted_output_invalid_json_fails() {
        let result = deserialize_encrypted_output("not json");
        assert!(result.is_err());
    }

    #[test]
    fn test_encrypted_output_all_schemes_roundtrip() {
        let schemes = [
            EncryptionScheme::Aes256Gcm,
            EncryptionScheme::ChaCha20Poly1305,
            EncryptionScheme::HybridMlKem512Aes256Gcm,
            EncryptionScheme::HybridMlKem768Aes256Gcm,
            EncryptionScheme::HybridMlKem1024Aes256Gcm,
        ];
        for scheme in &schemes {
            let output = EncryptedOutput::new(
                scheme.clone(),
                vec![1, 2, 3],
                vec![0u8; 12],
                vec![0u8; 16],
                if scheme.requires_hybrid_key() {
                    Some(HybridComponents::new(vec![0xAA; 32], vec![0xBB; 32]))
                } else {
                    None
                },
                42,
                None,
            );
            let json = serialize_encrypted_output(&output).unwrap();
            let restored = deserialize_encrypted_output(&json).unwrap();
            assert_eq!(output.scheme(), restored.scheme(), "scheme mismatch for {:?}", scheme);
        }
    }

    #[test]
    fn test_serializable_encrypted_output_clone_debug_work_correctly_succeeds() {
        let output = make_encrypted_output_symmetric();
        let ser = SerializableEncryptedOutput::from(&output);
        let cloned = ser.clone();
        assert_eq!(cloned.scheme, ser.scheme);
        let debug = format!("{:?}", ser);
        assert!(debug.contains("SerializableEncryptedOutput"));
    }

    // --- Serializable struct debug/clone ---

    #[test]
    fn test_serializable_signed_data_clone_debug_work_correctly_succeeds() {
        let original = make_signed_data();
        let ser = SerializableSignedData::from(&original);
        let cloned = ser.clone();
        assert_eq!(cloned.scheme, ser.scheme);
        let debug = format!("{:?}", ser);
        assert!(debug.contains("SerializableSignedData"));
    }

    #[test]
    fn test_serializable_keypair_debug_succeeds() {
        let original = make_keypair();
        let ser = SerializableKeyPair::from(&original);
        let debug = format!("{:?}", ser);
        assert!(debug.contains("SerializableKeyPair"));
    }

    #[test]
    fn test_serializable_keypair_two_instances_from_same_source_are_equal() {
        // Replacement for the removed clone test: two independently-constructed
        // instances from the same source key serialize to the same bytes for
        // both public and private components.
        let original = make_keypair();
        let ser_a = SerializableKeyPair::from(&original);
        let ser_b = SerializableKeyPair::from(&original);
        assert_eq!(ser_a.public_key, ser_b.public_key);
        assert_eq!(ser_a.private_key, ser_b.private_key);
    }
}