diff --git a/mft.xcodeproj/project.pbxproj b/mft.xcodeproj/project.pbxproj
index eb047ec..6b39b9b 100644
--- a/mft.xcodeproj/project.pbxproj
+++ b/mft.xcodeproj/project.pbxproj
@@ -7,6 +7,8 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		570DF26CE3885F940F090C90 /* MFTKeyGenerator.swift in Sources */ = {isa = PBXBuildFile; fileRef = 19C24E153DFC07E24B3B2A85 /* MFTKeyGenerator.swift */; };
+		A7C81C84D7DA6BFD1E7B9CEE /* MFTKeyGenerator.swift in Sources */ = {isa = PBXBuildFile; fileRef = 19C24E153DFC07E24B3B2A85 /* MFTKeyGenerator.swift */; };
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@@ -45,6 +47,7 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
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@@ -141,6 +144,7 @@
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 				C116CC2C2CC182200053B71A /* Localizable.xcstrings */,
 				C1E0728C2DCD2E0900FDADF5 /* PrivacyInfo.xcprivacy */,
+				19C24E153DFC07E24B3B2A85 /* MFTKeyGenerator.swift */,
 			);
 			path = mft;
 			sourceTree = "<group>";
@@ -335,6 +339,7 @@
 				C10B3EB227A7D05200A19857 /* NSString+iconv.m in Sources */,
 				C10B3EB327A7D05200A19857 /* MFTSftpItem.swift in Sources */,
 				C10B3EB427A7D05200A19857 /* MFTSftpConnection.swift in Sources */,
+				A7C81C84D7DA6BFD1E7B9CEE /* MFTKeyGenerator.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
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@@ -345,6 +350,7 @@
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 				C1D2B33127A42788004D9ACE /* MFTSftpItem.swift in Sources */,
 				C1D2B2D727A3EE58004D9ACE /* MFTSftpConnection.swift in Sources */,
+				570DF26CE3885F940F090C90 /* MFTKeyGenerator.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/mft/MFTKeyGenerator.swift b/mft/MFTKeyGenerator.swift
new file mode 100644
index 0000000..1586b50
--- /dev/null
+++ b/mft/MFTKeyGenerator.swift
@@ -0,0 +1,128 @@
+//
+//  MFTKeyGenerator.swift
+//  mft
+//
+//  Copyright © 2026 Marcin Labenski. All rights reserved.
+//
+
+import Foundation
+@_implementationOnly import libssh
+
+/// A newly generated SSH key pair.
+///
+/// The private half is what the client keeps and must be protected. The
+/// public half is what goes in the server's authorized_keys.
+@objcMembers public class MFTKeyPair: NSObject {
+    /// The private key, PEM wrapped and encrypted when a passphrase was given.
+    /// Ed25519 keys come out in OpenSSH format, RSA and ECDSA keys in PKCS#8.
+    public let privateKey: String
+    /// One authorized_keys line, without a trailing comment.
+    public let publicKey: String
+    /// The algorithm, as named on the wire, such as "ssh-ed25519".
+    public let keyType: String
+
+    init(privateKey: String, publicKey: String, keyType: String) {
+        self.privateKey = privateKey
+        self.publicKey = publicKey
+        self.keyType = keyType
+    }
+}
+
+/// Which kind of key to generate.
+@objc public enum MFTKeyType: Int {
+    /// Small, fast, and the sensible default for a new key.
+    case ed25519
+    case rsa4096
+    case ecdsa256
+
+    var sshType: ssh_keytypes_e {
+        switch self {
+        case .ed25519: return SSH_KEYTYPE_ED25519
+        case .rsa4096: return SSH_KEYTYPE_RSA
+        case .ecdsa256: return SSH_KEYTYPE_ECDSA_P256
+        }
+    }
+
+    /// The RSA modulus size to ask for, where the type does not already imply
+    /// the key size. libssh defaults to 3072 bits, so 4096 has to be requested.
+    var rsaKeySize: Int32? {
+        switch self {
+        case .rsa4096: return 4096
+        case .ed25519, .ecdsa256: return nil
+        }
+    }
+}
+
+@objcMembers public class MFTKeyGenerator: NSObject {
+
+    /// Generates an SSH key pair.
+    ///
+    /// Needs no connection: this is local key material, made before there is
+    /// anything to connect to.
+    /// - Parameters:
+    ///     - type: The algorithm to use.
+    ///     - passphrase: Encrypts the private half. Pass nil or a blank string
+    ///       to leave it unencrypted.
+    /// - Returns: The generated pair.
+    /// - Throws: NSError on error.
+    public static func generate(type: MFTKeyType, passphrase: String? = nil) throws -> MFTKeyPair {
+        var context: ssh_pki_ctx?
+        if var bits = type.rsaKeySize {
+            context = ssh_pki_ctx_new()
+            guard let context,
+                  ssh_pki_ctx_options_set(context, SSH_PKI_OPTION_RSA_KEY_SIZE, &bits) == SSH_OK
+            else {
+                throw NSError(
+                    domain: "mft",
+                    code: MFTErrorCode.wrong_keyfile.rawValue,
+                    userInfo: [NSLocalizedDescriptionKey: "Could not set the key size."]
+                )
+            }
+        }
+        defer { if let context { ssh_pki_ctx_free(context) } }
+
+        var key: ssh_key?
+        guard ssh_pki_generate_key(type.sshType, context, &key) == SSH_OK, let key else {
+            throw NSError(
+                domain: "mft",
+                code: MFTErrorCode.wrong_keyfile.rawValue,
+                userInfo: [NSLocalizedDescriptionKey: "Could not generate a key."]
+            )
+        }
+        defer { ssh_key_free(key) }
+
+        var privateBuffer: UnsafeMutablePointer<CChar>?
+        let secret = (passphrase?.isEmpty == false) ? passphrase : nil
+        guard ssh_pki_export_privkey_base64(key, secret, nil, nil, &privateBuffer) == SSH_OK,
+              let privateBuffer
+        else {
+            throw NSError(
+                domain: "mft",
+                code: MFTErrorCode.wrong_keyfile.rawValue,
+                userInfo: [NSLocalizedDescriptionKey: "Could not export the generated private key."]
+            )
+        }
+        defer { ssh_string_free_char(privateBuffer) }
+
+        var publicBuffer: UnsafeMutablePointer<CChar>?
+        guard ssh_pki_export_pubkey_base64(key, &publicBuffer) == SSH_OK, let publicBuffer else {
+            throw NSError(
+                domain: "mft",
+                code: MFTErrorCode.wrong_keyfile.rawValue,
+                userInfo: [NSLocalizedDescriptionKey: "Could not export the generated public key."]
+            )
+        }
+        defer { ssh_string_free_char(publicBuffer) }
+
+        let typeName = String(cString: ssh_key_type_to_char(ssh_key_type(key)))
+        // ssh_pki_export_pubkey_base64 returns the payload alone, while
+        // authorized_keys wants the algorithm in front of it.
+        let publicLine = "\(typeName) \(String(cString: publicBuffer))"
+
+        return MFTKeyPair(
+            privateKey: String(cString: privateBuffer),
+            publicKey: publicLine,
+            keyType: typeName
+        )
+    }
+}