diff --git a/src/main/java/org/qortal/api/Security.java b/src/main/java/org/qortal/api/Security.java
index 2449f781..448f951a 100644
--- a/src/main/java/org/qortal/api/Security.java
+++ b/src/main/java/org/qortal/api/Security.java
@@ -5,10 +5,20 @@ import java.net.UnknownHostException;
 
 import javax.servlet.http.HttpServletRequest;
 
-public class Security {
+import org.qortal.settings.Settings;
+
+public abstract class Security {
+
+	public static final String API_KEY_HEADER = "X-API-KEY";
 
-	// TODO: replace with proper authentication
 	public static void checkApiCallAllowed(HttpServletRequest request) {
+		String expectedApiKey = Settings.getInstance().getApiKey();
+		String passedApiKey = request.getHeader(API_KEY_HEADER);
+
+		if ((expectedApiKey != null && !expectedApiKey.equals(passedApiKey)) ||
+				(passedApiKey != null && !passedApiKey.equals(expectedApiKey)))
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.UNAUTHORIZED);
+
 		InetAddress remoteAddr;
 		try {
 			remoteAddr = InetAddress.getByName(request.getRemoteAddr());
@@ -19,4 +29,5 @@ public class Security {
 		if (!remoteAddr.isLoopbackAddress())
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.UNAUTHORIZED);
 	}
+
 }
diff --git a/src/main/java/org/qortal/api/resource/AddressesResource.java b/src/main/java/org/qortal/api/resource/AddressesResource.java
index 39b4bd71..20e4da5a 100644
--- a/src/main/java/org/qortal/api/resource/AddressesResource.java
+++ b/src/main/java/org/qortal/api/resource/AddressesResource.java
@@ -7,6 +7,7 @@ import io.swagger.v3.oas.annotations.media.Content;
 import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.parameters.RequestBody;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.security.SecurityRequirement;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
 import java.math.BigDecimal;
@@ -473,6 +474,7 @@ public class AddressesResource {
 		}
 	)
 	@ApiErrors({ApiError.TRANSACTION_INVALID, ApiError.INVALID_DATA, ApiError.TRANSFORMATION_ERROR, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String computePublicize(String rawBytes58) {
 		Security.checkApiCallAllowed(request);
 
diff --git a/src/main/java/org/qortal/api/resource/AdminResource.java b/src/main/java/org/qortal/api/resource/AdminResource.java
index 6fbadb96..fc761501 100644
--- a/src/main/java/org/qortal/api/resource/AdminResource.java
+++ b/src/main/java/org/qortal/api/resource/AdminResource.java
@@ -8,6 +8,7 @@ import io.swagger.v3.oas.annotations.media.Content;
 import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.parameters.RequestBody;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.security.SecurityRequirement;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
 import java.io.IOException;
@@ -133,6 +134,7 @@ public class AdminResource {
 			)
 		}
 	)
+	@SecurityRequirement(name = "apiKey")
 	public NodeStatus status() {
 		Security.checkApiCallAllowed(request);
 
@@ -153,6 +155,7 @@ public class AdminResource {
 			)
 		}
 	)
+	@SecurityRequirement(name = "apiKey")
 	public String shutdown() {
 		Security.checkApiCallAllowed(request);
 
@@ -181,6 +184,7 @@ public class AdminResource {
 		}
 	)
 	@ApiErrors({ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public ActivitySummary summary() {
 		Security.checkApiCallAllowed(request);
 
@@ -226,6 +230,7 @@ public class AdminResource {
 			)
 		}
 	)
+	@SecurityRequirement(name = "apiKey")
 	public Controller.StatsSnapshot getEngineStats() {
 		Security.checkApiCallAllowed(request);
 
@@ -244,6 +249,7 @@ public class AdminResource {
 		}
 	)
 	@ApiErrors({ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public List<MintingAccountData> getMintingAccounts() {
 		Security.checkApiCallAllowed(request);
 
@@ -290,6 +296,7 @@ public class AdminResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PRIVATE_KEY, ApiError.REPOSITORY_ISSUE, ApiError.CANNOT_MINT})
+	@SecurityRequirement(name = "apiKey")
 	public String addMintingAccount(String seed58) {
 		Security.checkApiCallAllowed(request);
 
@@ -342,6 +349,7 @@ public class AdminResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PRIVATE_KEY, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String deleteMintingAccount(String key58) {
 		Security.checkApiCallAllowed(request);
 
@@ -441,6 +449,7 @@ public class AdminResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_HEIGHT, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String orphan(String targetHeightString) {
 		Security.checkApiCallAllowed(request);
 
@@ -482,6 +491,7 @@ public class AdminResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_DATA, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String forceSync(String targetPeerAddress) {
 		Security.checkApiCallAllowed(request);
 
@@ -527,6 +537,7 @@ public class AdminResource {
 		description = "Requires enough free space to rebuild repository. This will pause your node for a while."
 	)
 	@ApiErrors({ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public void performRepositoryMaintenance() {
 		Security.checkApiCallAllowed(request);
 
diff --git a/src/main/java/org/qortal/api/resource/ApiDefinition.java b/src/main/java/org/qortal/api/resource/ApiDefinition.java
index ae7de00c..f9ec7459 100644
--- a/src/main/java/org/qortal/api/resource/ApiDefinition.java
+++ b/src/main/java/org/qortal/api/resource/ApiDefinition.java
@@ -1,11 +1,17 @@
 package org.qortal.api.resource;
 
 import io.swagger.v3.oas.annotations.OpenAPIDefinition;
+import io.swagger.v3.oas.annotations.enums.SecuritySchemeIn;
+import io.swagger.v3.oas.annotations.enums.SecuritySchemeType;
 import io.swagger.v3.oas.annotations.extensions.Extension;
 import io.swagger.v3.oas.annotations.extensions.ExtensionProperty;
 import io.swagger.v3.oas.annotations.info.Info;
+import io.swagger.v3.oas.annotations.security.SecurityScheme;
+import io.swagger.v3.oas.annotations.security.SecuritySchemes;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
+import org.qortal.api.Security;
+
 @OpenAPIDefinition(
 		info = @Info( title = "Qortal API", description = "NOTE: byte-arrays are encoded in Base58" ),
 		tags = {
@@ -30,5 +36,9 @@ import io.swagger.v3.oas.annotations.tags.Tag;
 			})
 		}
 )
+@SecuritySchemes({
+	@SecurityScheme(name = "basicAuth", type = SecuritySchemeType.HTTP, scheme = "basic"),
+	@SecurityScheme(name = "apiKey", type = SecuritySchemeType.APIKEY, in = SecuritySchemeIn.HEADER, paramName = Security.API_KEY_HEADER)
+})
 public class ApiDefinition {
 }
\ No newline at end of file
diff --git a/src/main/java/org/qortal/api/resource/ChatResource.java b/src/main/java/org/qortal/api/resource/ChatResource.java
index 9a8fc8d5..6ad7d6ea 100644
--- a/src/main/java/org/qortal/api/resource/ChatResource.java
+++ b/src/main/java/org/qortal/api/resource/ChatResource.java
@@ -7,6 +7,7 @@ import io.swagger.v3.oas.annotations.media.Content;
 import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.parameters.RequestBody;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.security.SecurityRequirement;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
 import java.util.List;
@@ -156,6 +157,7 @@ public class ChatResource {
 		}
 	)
 	@ApiErrors({ApiError.TRANSACTION_INVALID, ApiError.TRANSFORMATION_ERROR, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String buildChat(ChatTransactionData transactionData) {
 		Security.checkApiCallAllowed(request);
 
@@ -203,6 +205,7 @@ public class ChatResource {
 		}
 	)
 	@ApiErrors({ApiError.TRANSACTION_INVALID, ApiError.INVALID_DATA, ApiError.TRANSFORMATION_ERROR, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String buildChat(String rawBytes58) {
 		Security.checkApiCallAllowed(request);
 
diff --git a/src/main/java/org/qortal/api/resource/CrossChainResource.java b/src/main/java/org/qortal/api/resource/CrossChainResource.java
index c8ab6527..9e46b245 100644
--- a/src/main/java/org/qortal/api/resource/CrossChainResource.java
+++ b/src/main/java/org/qortal/api/resource/CrossChainResource.java
@@ -7,6 +7,7 @@ import io.swagger.v3.oas.annotations.media.Content;
 import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.parameters.RequestBody;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.security.SecurityRequirement;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
 import java.math.BigDecimal;
@@ -155,6 +156,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_DATA, ApiError.INVALID_REFERENCE, ApiError.TRANSFORMATION_ERROR, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String buildTrade(CrossChainBuildRequest tradeRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -250,6 +252,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.INVALID_CRITERIA, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String buildTradeMessage(CrossChainTradeRequest tradeRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -333,6 +336,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.INVALID_DATA, ApiError.INVALID_CRITERIA, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String buildRedeemMessage(CrossChainSecretRequest secretRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -404,6 +408,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.INVALID_CRITERIA, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String buildCancelMessage(CrossChainCancelRequest cancelRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -459,6 +464,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String deriveP2shA(CrossChainBitcoinTemplateRequest templateRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -485,6 +491,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String deriveP2shB(CrossChainBitcoinTemplateRequest templateRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -542,6 +549,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public CrossChainBitcoinP2SHStatus checkP2shA(CrossChainBitcoinTemplateRequest templateRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -568,6 +576,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public CrossChainBitcoinP2SHStatus checkP2shB(CrossChainBitcoinTemplateRequest templateRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -656,6 +665,7 @@ public class CrossChainResource {
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN,
 		ApiError.BTC_TOO_SOON, ApiError.BTC_BALANCE_ISSUE, ApiError.BTC_NETWORK_ISSUE, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String refundP2shA(CrossChainBitcoinRefundRequest refundRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -683,6 +693,7 @@ public class CrossChainResource {
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN,
 		ApiError.BTC_TOO_SOON, ApiError.BTC_BALANCE_ISSUE, ApiError.BTC_NETWORK_ISSUE, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String refundP2shB(CrossChainBitcoinRefundRequest refundRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -793,6 +804,7 @@ public class CrossChainResource {
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN,
 		ApiError.BTC_TOO_SOON, ApiError.BTC_BALANCE_ISSUE, ApiError.BTC_NETWORK_ISSUE, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String redeemP2shA(CrossChainBitcoinRedeemRequest redeemRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -821,6 +833,7 @@ public class CrossChainResource {
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.ADDRESS_UNKNOWN,
 		ApiError.BTC_TOO_SOON, ApiError.BTC_BALANCE_ISSUE, ApiError.BTC_NETWORK_ISSUE, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String redeemP2shB(CrossChainBitcoinRedeemRequest redeemRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -935,6 +948,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PRIVATE_KEY})
+	@SecurityRequirement(name = "apiKey")
 	public String getBitcoinWalletBalance(String xprv58) {
 		Security.checkApiCallAllowed(request);
 
@@ -969,6 +983,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PRIVATE_KEY, ApiError.INVALID_CRITERIA, ApiError.INVALID_ADDRESS, ApiError.BTC_BALANCE_ISSUE, ApiError.BTC_NETWORK_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String sendBitcoin(BitcoinSendRequest bitcoinSendRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -1019,6 +1034,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public List<TradeBotData> getTradeBotStates() {
 		Security.checkApiCallAllowed(request);
 
@@ -1049,6 +1065,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String tradeBotCreator(TradeBotCreateRequest tradeBotCreateRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -1104,6 +1121,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_PUBLIC_KEY, ApiError.INVALID_ADDRESS, ApiError.INVALID_CRITERIA, ApiError.BTC_BALANCE_ISSUE, ApiError.BTC_NETWORK_ISSUE, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String tradeBotResponder(TradeBotRespondRequest tradeBotRespondRequest) {
 		Security.checkApiCallAllowed(request);
 
@@ -1168,6 +1186,7 @@ public class CrossChainResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_ADDRESS, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public String tradeBotDelete(String tradePrivateKey58) {
 		Security.checkApiCallAllowed(request);
 
diff --git a/src/main/java/org/qortal/api/resource/PeersResource.java b/src/main/java/org/qortal/api/resource/PeersResource.java
index a66fef4a..70f0e3e9 100644
--- a/src/main/java/org/qortal/api/resource/PeersResource.java
+++ b/src/main/java/org/qortal/api/resource/PeersResource.java
@@ -6,6 +6,7 @@ import io.swagger.v3.oas.annotations.media.Content;
 import io.swagger.v3.oas.annotations.media.Schema;
 import io.swagger.v3.oas.annotations.parameters.RequestBody;
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.security.SecurityRequirement;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
 import java.net.InetSocketAddress;
@@ -131,6 +132,7 @@ public class PeersResource {
 			)
 		}
 	)
+	@SecurityRequirement(name = "apiKey")
 	public ExecuteProduceConsume.StatsSnapshot getEngineStats() {
 		Security.checkApiCallAllowed(request);
 
@@ -168,6 +170,7 @@ public class PeersResource {
 	@ApiErrors({
 		ApiError.INVALID_NETWORK_ADDRESS, ApiError.REPOSITORY_ISSUE
 	})
+	@SecurityRequirement(name = "apiKey")
 	public String addPeer(String address) {
 		Security.checkApiCallAllowed(request);
 
@@ -222,6 +225,7 @@ public class PeersResource {
 	@ApiErrors({
 		ApiError.INVALID_NETWORK_ADDRESS, ApiError.REPOSITORY_ISSUE
 	})
+	@SecurityRequirement(name = "apiKey")
 	public String removePeer(String address) {
 		Security.checkApiCallAllowed(request);
 
@@ -257,6 +261,7 @@ public class PeersResource {
 	@ApiErrors({
 		ApiError.REPOSITORY_ISSUE
 	})
+	@SecurityRequirement(name = "apiKey")
 	public String removeKnownPeers(String address) {
 		Security.checkApiCallAllowed(request);
 
@@ -296,6 +301,7 @@ public class PeersResource {
 		}
 	)
 	@ApiErrors({ApiError.INVALID_DATA, ApiError.REPOSITORY_ISSUE})
+	@SecurityRequirement(name = "apiKey")
 	public List<BlockSummaryData> commonBlock(String targetPeerAddress) {
 		Security.checkApiCallAllowed(request);
 
diff --git a/src/main/java/org/qortal/settings/Settings.java b/src/main/java/org/qortal/settings/Settings.java
index 1a989c2e..1d33dcb7 100644
--- a/src/main/java/org/qortal/settings/Settings.java
+++ b/src/main/java/org/qortal/settings/Settings.java
@@ -65,6 +65,7 @@ public class Settings {
 		"::1", "127.0.0.1"
 	};
 	private Boolean apiRestricted;
+	private String apiKey = null;
 	private boolean apiLoggingEnabled = false;
 	private boolean apiDocumentationEnabled = false;
 	// Both of these need to be set for API to use SSL
@@ -275,6 +276,9 @@ public class Settings {
 		// Validation goes here
 		if (this.minBlockchainPeers < 1)
 			throwValidationError("minBlockchainPeers must be at least 1");
+
+		if (this.apiKey != null && this.apiKey.trim().length() < 8)
+			throwValidationError("apiKey must be at least 8 characters");
 	}
 
 	// Getters / setters
@@ -323,6 +327,10 @@ public class Settings {
 		return !BlockChain.getInstance().isTestChain();
 	}
 
+	public String getApiKey() {
+		return this.apiKey;
+	}
+
 	public boolean isApiLoggingEnabled() {
 		return this.apiLoggingEnabled;
 	}