diff --git a/Sources/WebAuthn/Ceremonies/Authentication/AuthenticationCredential.swift b/Sources/WebAuthn/Ceremonies/Authentication/AuthenticationCredential.swift
index 6237cc6..744423e 100644
--- a/Sources/WebAuthn/Ceremonies/Authentication/AuthenticationCredential.swift
+++ b/Sources/WebAuthn/Ceremonies/Authentication/AuthenticationCredential.swift
@@ -34,7 +34,7 @@ public struct AuthenticationCredential: Sendable {
     public let type: CredentialType
 }
 
-extension AuthenticationCredential: Decodable {
+extension AuthenticationCredential: Codable {
     public init(from decoder: any Decoder) throws {
         let container = try decoder.container(keyedBy: CodingKeys.self)
 
@@ -44,6 +44,17 @@ extension AuthenticationCredential: Decodable {
         authenticatorAttachment = try container.decodeIfPresent(AuthenticatorAttachment.self, forKey: .authenticatorAttachment)
         type = try container.decode(CredentialType.self, forKey: .type)
     }
+    
+    public func encode(to encoder: any Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+
+        try container.encode(id, forKey: .id)
+        try container.encode(rawID.base64URLEncodedString(), forKey: .rawID)
+        try container.encode(response, forKey: .response)
+        try container.encodeIfPresent(authenticatorAttachment, forKey: .authenticatorAttachment)
+        try container.encode(type, forKey: .type)
+    }
+
 
     private enum CodingKeys: String, CodingKey {
         case id
diff --git a/Sources/WebAuthn/Ceremonies/Authentication/AuthenticatorAssertionResponse.swift b/Sources/WebAuthn/Ceremonies/Authentication/AuthenticatorAssertionResponse.swift
index cf9580b..2daa5df 100644
--- a/Sources/WebAuthn/Ceremonies/Authentication/AuthenticatorAssertionResponse.swift
+++ b/Sources/WebAuthn/Ceremonies/Authentication/AuthenticatorAssertionResponse.swift
@@ -48,7 +48,7 @@ public struct AuthenticatorAssertionResponse: Sendable {
     public let attestationObject: [UInt8]?
 }
 
-extension AuthenticatorAssertionResponse: Decodable {
+extension AuthenticatorAssertionResponse: Codable {
     public init(from decoder: any Decoder) throws {
         let container = try decoder.container(keyedBy: CodingKeys.self)
 
@@ -58,6 +58,17 @@ extension AuthenticatorAssertionResponse: Decodable {
         userHandle = try container.decodeBytesFromURLEncodedBase64IfPresent(forKey: .userHandle)
         attestationObject = try container.decodeBytesFromURLEncodedBase64IfPresent(forKey: .attestationObject)
     }
+    
+    public func encode(to encoder: any Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+
+        try container.encode(clientDataJSON.base64URLEncodedString(), forKey: .clientDataJSON)
+        try container.encode(authenticatorData.base64URLEncodedString(), forKey: .authenticatorData)
+        try container.encode(signature.base64URLEncodedString(), forKey: .signature)
+        try container.encodeIfPresent(userHandle?.base64URLEncodedString(), forKey: .userHandle)
+        try container.encodeIfPresent(attestationObject?.base64URLEncodedString(), forKey: .attestationObject)
+    }
+
 
     private enum CodingKeys: String, CodingKey {
         case clientDataJSON
diff --git a/Sources/WebAuthn/Ceremonies/Authentication/PublicKeyCredentialRequestOptions.swift b/Sources/WebAuthn/Ceremonies/Authentication/PublicKeyCredentialRequestOptions.swift
index 737d905..afe8980 100644
--- a/Sources/WebAuthn/Ceremonies/Authentication/PublicKeyCredentialRequestOptions.swift
+++ b/Sources/WebAuthn/Ceremonies/Authentication/PublicKeyCredentialRequestOptions.swift
@@ -18,30 +18,30 @@ import Foundation
 /// When encoding using `Encodable`, the byte arrays are encoded as base64url.
 ///
 /// - SeeAlso: https://www.w3.org/TR/webauthn-2/#dictionary-assertion-options
-public struct PublicKeyCredentialRequestOptions: Encodable, Sendable {
+public struct PublicKeyCredentialRequestOptions: Codable, Sendable {
     /// A challenge that the authenticator signs, along with other data, when producing an authentication assertion
     ///
     /// When encoding using `Encodable` this is encoded as base64url.
-    public let challenge: [UInt8]
+    public var challenge: [UInt8]
 
     /// A time, in seconds, that the caller is willing to wait for the call to complete. This is treated as a
     /// hint, and may be overridden by the client.
     ///
     /// - Note: When encoded, this value is represented in milleseconds as a ``UInt32``.
     /// See https://www.w3.org/TR/webauthn-2/#dictionary-assertion-options
-    public let timeout: Duration?
+    public var timeout: Duration?
 
     /// The ID of the Relying Party making the request.
     ///
     /// This is configured on ``WebAuthnManager`` before its ``WebAuthnManager/beginAuthentication(timeout:allowCredentials:userVerification:)`` method is called.
     /// - Note: When encoded, this field appears as `rpId` to match the expectations of `navigator.credentials.get()`.
-    public let relyingPartyID: String
+    public var relyingPartyID: String
 
     /// Optionally used by the client to find authenticators eligible for this authentication ceremony.
-    public let allowCredentials: [PublicKeyCredentialDescriptor]?
+    public var allowCredentials: [PublicKeyCredentialDescriptor]?
 
     /// Specifies whether the user should be verified during the authentication ceremony.
-    public let userVerification: UserVerificationRequirement?
+    public var userVerification: UserVerificationRequirement?
 
     // let extensions: [String: Any]
 
@@ -50,15 +50,42 @@ public struct PublicKeyCredentialRequestOptions: Encodable, Sendable {
 
         try container.encode(challenge.base64URLEncodedString(), forKey: .challenge)
         try container.encodeIfPresent(timeout?.milliseconds, forKey: .timeout)
-        try container.encode(relyingPartyID, forKey: .rpID)
+        try container.encode(relyingPartyID, forKey: .relyingPartyID)
         try container.encodeIfPresent(allowCredentials, forKey: .allowCredentials)
         try container.encodeIfPresent(userVerification, forKey: .userVerification)
     }
+    
+    public init(
+        challenge: [UInt8],
+        timeout: Duration?,
+        relyingPartyID: String,
+        allowCredentials: [PublicKeyCredentialDescriptor]?,
+        userVerification: UserVerificationRequirement?
+    ) {
+        self.challenge = challenge
+        self.timeout = timeout
+        self.relyingPartyID = relyingPartyID
+        self.allowCredentials = allowCredentials
+        self.userVerification = userVerification
+    }
+
+    public init(from decoder: any Decoder) throws {
+        let values = try decoder.container(keyedBy: CodingKeys.self)
+
+        self.challenge = try values.decodeBytesFromURLEncodedBase64(forKey: .challenge)
+
+        if let timeout = try values.decodeIfPresent(UInt32.self, forKey: .timeout) {
+            self.timeout = .milliseconds(timeout)
+        }
+        self.relyingPartyID = try values.decode(String.self, forKey: .relyingPartyID)
+        self.allowCredentials = try values.decodeIfPresent([PublicKeyCredentialDescriptor].self, forKey: .allowCredentials)
+        self.userVerification = try values.decodeIfPresent(UserVerificationRequirement.self, forKey: .userVerification)
+    }
 
     private enum CodingKeys: String, CodingKey {
         case challenge
         case timeout
-        case rpID = "rpId"
+        case relyingPartyID = "rpId"
         case allowCredentials
         case userVerification
     }
@@ -67,7 +94,7 @@ public struct PublicKeyCredentialRequestOptions: Encodable, Sendable {
 /// Information about a generated credential.
 ///
 /// When encoding using `Encodable`, `id` is encoded as base64url.
-public struct PublicKeyCredentialDescriptor: Equatable, Encodable, Sendable {
+public struct PublicKeyCredentialDescriptor: Equatable, Codable, Sendable {
     /// Defines hints as to how clients might communicate with a particular authenticator in order to obtain an
     /// assertion for a specific credential
     public struct AuthenticatorTransport: UnreferencedStringEnumeration, Sendable {
@@ -119,6 +146,14 @@ public struct PublicKeyCredentialDescriptor: Equatable, Encodable, Sendable {
         try container.encode(id.base64URLEncodedString(), forKey: .id)
         try container.encodeIfPresent(transports, forKey: .transports)
     }
+    
+    public init(from decoder: any Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+
+        self.type = try container.decode(CredentialType.self, forKey: .type)
+        self.id = try container.decodeBytesFromURLEncodedBase64(forKey: .id)
+        self.transports = try container.decodeIfPresent([AuthenticatorTransport].self, forKey: .transports) ?? []
+    }
 
     private enum CodingKeys: String, CodingKey {
         case type
diff --git a/Sources/WebAuthn/Ceremonies/Registration/AuthenticatorAttestationResponse.swift b/Sources/WebAuthn/Ceremonies/Registration/AuthenticatorAttestationResponse.swift
index b12d3b7..343dc31 100644
--- a/Sources/WebAuthn/Ceremonies/Registration/AuthenticatorAttestationResponse.swift
+++ b/Sources/WebAuthn/Ceremonies/Registration/AuthenticatorAttestationResponse.swift
@@ -29,13 +29,21 @@ public struct AuthenticatorAttestationResponse: Sendable {
     public let attestationObject: [UInt8]
 }
 
-extension AuthenticatorAttestationResponse: Decodable {
+extension AuthenticatorAttestationResponse: Codable {
     public init(from decoder: any Decoder) throws {
         let container = try decoder.container(keyedBy: CodingKeys.self)
 
         clientDataJSON = try container.decodeBytesFromURLEncodedBase64(forKey: .clientDataJSON)
         attestationObject = try container.decodeBytesFromURLEncodedBase64(forKey: .attestationObject)
     }
+    
+    public func encode(to encoder: any Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+
+        try container.encode(clientDataJSON.base64URLEncodedString(), forKey: .clientDataJSON)
+        try container.encode(attestationObject.base64URLEncodedString(), forKey: .attestationObject)
+    }
+
 
     private enum CodingKeys: String, CodingKey {
         case clientDataJSON
diff --git a/Sources/WebAuthn/Ceremonies/Registration/PublicKeyCredentialCreationOptions.swift b/Sources/WebAuthn/Ceremonies/Registration/PublicKeyCredentialCreationOptions.swift
index 9fdfabf..2d0976b 100644
--- a/Sources/WebAuthn/Ceremonies/Registration/PublicKeyCredentialCreationOptions.swift
+++ b/Sources/WebAuthn/Ceremonies/Registration/PublicKeyCredentialCreationOptions.swift
@@ -19,7 +19,7 @@ import Foundation
 /// `Encodable` byte arrays are base64url encoded.
 ///
 /// - SeeAlso: https://www.w3.org/TR/webauthn-2/#dictionary-makecredentialoptions
-public struct PublicKeyCredentialCreationOptions: Encodable, Sendable {
+public struct PublicKeyCredentialCreationOptions: Codable, Sendable {
     /// A byte array randomly generated by the Relying Party. Should be at least 16 bytes long to ensure sufficient
     /// entropy.
     ///
@@ -28,24 +28,24 @@ public struct PublicKeyCredentialCreationOptions: Encodable, Sendable {
     public let challenge: [UInt8]
 
     /// Contains names and an identifier for the user account performing the registration
-    public let user: PublicKeyCredentialUserEntity
+    public var user: PublicKeyCredentialUserEntity
 
     /// Contains a name and an identifier for the Relying Party responsible for the request
-    public let relyingParty: PublicKeyCredentialRelyingPartyEntity
+    public var relyingParty: PublicKeyCredentialRelyingPartyEntity
 
     /// A list of key types and signature algorithms the Relying Party supports. Ordered from most preferred to least
     /// preferred.
-    public let publicKeyCredentialParameters: [PublicKeyCredentialParameters]
+    public var publicKeyCredentialParameters: [PublicKeyCredentialParameters]
 
     /// A time, in seconds, that the caller is willing to wait for the call to complete. This is treated as a
     /// hint, and may be overridden by the client.
     ///
     /// - Note: When encoded, this value is represented in milleseconds as a ``UInt32``.
-    public let timeout: Duration?
+    public var timeout: Duration?
 
     /// Sets the Relying Party's preference for attestation conveyance. At the time of writing only `none` is
     /// supported.
-    public let attestation: AttestationConveyancePreference
+    public var attestation: AttestationConveyancePreference
 
     public func encode(to encoder: any Encoder) throws {
         var container = encoder.container(keyedBy: CodingKeys.self)
@@ -57,6 +57,35 @@ public struct PublicKeyCredentialCreationOptions: Encodable, Sendable {
         try container.encodeIfPresent(timeout?.milliseconds, forKey: .timeout)
         try container.encode(attestation, forKey: .attestation)
     }
+    
+    public init(from decoder: any Decoder) throws {
+        let values = try decoder.container(keyedBy: CodingKeys.self)
+        
+        self.challenge = try values.decodeBytesFromURLEncodedBase64(forKey: .challenge)
+        self.user = try values.decode(PublicKeyCredentialUserEntity.self, forKey: .user)
+        self.relyingParty = try values.decode(PublicKeyCredentialRelyingPartyEntity.self, forKey: .relyingParty)
+        self.publicKeyCredentialParameters =  try values.decode([PublicKeyCredentialParameters].self, forKey: .publicKeyCredentialParameters)
+        if let timeout = try values.decodeIfPresent(UInt32.self, forKey: .timeout) {
+            self.timeout = .milliseconds(timeout)
+        }
+        self.attestation = try values.decode(AttestationConveyancePreference.self, forKey: .attestation)
+    }
+    
+    public init(
+        challenge: [UInt8],
+        user: PublicKeyCredentialUserEntity,
+        relyingParty: PublicKeyCredentialRelyingPartyEntity,
+        publicKeyCredentialParameters: [PublicKeyCredentialParameters],
+        timeout: Duration?,
+        attestation: AttestationConveyancePreference
+    ) {
+        self.challenge = challenge
+        self.user = user
+        self.relyingParty = relyingParty
+        self.publicKeyCredentialParameters = publicKeyCredentialParameters
+        self.timeout = timeout
+        self.attestation = attestation
+    }
 
     private enum CodingKeys: String, CodingKey {
         case challenge
@@ -70,7 +99,7 @@ public struct PublicKeyCredentialCreationOptions: Encodable, Sendable {
 
 // MARK: - Credential parameters
 /// From §5.3 (https://w3c.github.io/TR/webauthn/#dictionary-credential-params)
-public struct PublicKeyCredentialParameters: Equatable, Encodable, Sendable {
+public struct PublicKeyCredentialParameters: Equatable, Codable, Sendable {
     /// The type of credential to be created. At the time of writing always ``CredentialType/publicKey``.
     public let type: CredentialType
     /// The cryptographic signature algorithm with which the newly generated credential will be used, and thus also
@@ -87,6 +116,13 @@ public struct PublicKeyCredentialParameters: Equatable, Encodable, Sendable {
         self.type = type
         self.alg = alg
     }
+    
+    public init(from decoder: any Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+
+        self.type = try container.decode(CredentialType.self, forKey: .type)
+        self.alg = try container.decode(COSEAlgorithmIdentifier.self, forKey: .alg)
+    }
 }
 
 extension Array where Element == PublicKeyCredentialParameters {
@@ -103,14 +139,18 @@ extension Array where Element == PublicKeyCredentialParameters {
 /// From §5.4.2 (https://www.w3.org/TR/webauthn/#sctn-rp-credential-params).
 /// The PublicKeyCredentialRelyingPartyEntity dictionary is used to supply additional Relying Party attributes when
 /// creating a new credential.
-public struct PublicKeyCredentialRelyingPartyEntity: Encodable, Sendable {
+public struct PublicKeyCredentialRelyingPartyEntity: Codable, Sendable {
     /// A unique identifier for the Relying Party entity.
-    public let id: String
+    public var id: String
 
     /// A human-readable identifier for the Relying Party, intended only for display. For example, "ACME Corporation",
     /// "Wonderful Widgets, Inc." or "ОАО Примертех".
-    public let name: String
+    public var name: String
 
+    public init(id: String, name: String) {
+        self.id = id
+        self.name = name
+    }
 }
 
  /// From §5.4.3 (https://www.w3.org/TR/webauthn/#dictionary-user-credential-params)
@@ -118,7 +158,7 @@ public struct PublicKeyCredentialRelyingPartyEntity: Encodable, Sendable {
  /// creating a new credential.
  ///
  /// When encoding using `Encodable`, `id` is base64url encoded.
-public struct PublicKeyCredentialUserEntity: Encodable, Sendable {
+public struct PublicKeyCredentialUserEntity: Codable, Sendable {
     /// Generated by the Relying Party, unique to the user account, and must not contain personally identifying
     /// information about the user.
     ///
@@ -149,6 +189,15 @@ public struct PublicKeyCredentialUserEntity: Encodable, Sendable {
         try container.encode(name, forKey: .name)
         try container.encode(displayName, forKey: .displayName)
     }
+    
+    public init(from decoder: any Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+
+        self.id = try container.decodeBytesFromURLEncodedBase64(forKey: .id)
+        self.name = try container.decode(String.self, forKey: .name)
+        self.displayName = try container.decode(String.self, forKey: .displayName)
+    }
+
 
     private enum CodingKeys: String, CodingKey {
         case id
diff --git a/Sources/WebAuthn/Ceremonies/Registration/RegistrationCredential.swift b/Sources/WebAuthn/Ceremonies/Registration/RegistrationCredential.swift
index 2bc3f9f..02beecd 100644
--- a/Sources/WebAuthn/Ceremonies/Registration/RegistrationCredential.swift
+++ b/Sources/WebAuthn/Ceremonies/Registration/RegistrationCredential.swift
@@ -31,7 +31,7 @@ public struct RegistrationCredential: Sendable {
     public let attestationResponse: AuthenticatorAttestationResponse
 }
 
-extension RegistrationCredential: Decodable {
+extension RegistrationCredential: Codable {
     public init(from decoder: any Decoder) throws {
         let container = try decoder.container(keyedBy: CodingKeys.self)
 
@@ -47,6 +47,15 @@ extension RegistrationCredential: Decodable {
         self.rawID = rawID
         attestationResponse = try container.decode(AuthenticatorAttestationResponse.self, forKey: .attestationResponse)
     }
+    
+    public func encode(to encoder: any Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+
+        try container.encode(id, forKey: .id)
+        try container.encode(rawID.base64URLEncodedString(), forKey: .rawID)
+        try container.encode(attestationResponse, forKey: .attestationResponse)
+    }
+
 
     private enum CodingKeys: String, CodingKey {
         case id
diff --git a/Sources/WebAuthn/Ceremonies/Shared/COSE/COSEAlgorithmIdentifier.swift b/Sources/WebAuthn/Ceremonies/Shared/COSE/COSEAlgorithmIdentifier.swift
index adf2c2d..c25b2b6 100644
--- a/Sources/WebAuthn/Ceremonies/Shared/COSE/COSEAlgorithmIdentifier.swift
+++ b/Sources/WebAuthn/Ceremonies/Shared/COSE/COSEAlgorithmIdentifier.swift
@@ -17,7 +17,7 @@ import Crypto
 /// COSEAlgorithmIdentifier From §5.10.5. A number identifying a cryptographic algorithm. The algorithm
 /// identifiers SHOULD be values registered in the IANA COSE Algorithms registry
 /// [https://www.w3.org/TR/webauthn/#biblio-iana-cose-algs-reg], for instance, -7 for "ES256" and -257 for "RS256".
-public enum COSEAlgorithmIdentifier: Int, RawRepresentable, CaseIterable, Encodable, Sendable {
+public enum COSEAlgorithmIdentifier: Int, RawRepresentable, CaseIterable, Codable, Sendable {
     /// AlgES256 ECDSA with SHA-256
     case algES256 = -7
     /// AlgES384 ECDSA with SHA-384