diff --git a/sodium.php b/sodium.php
index d8727b0..709b21b 100644
--- a/sodium.php
+++ b/sodium.php
@@ -1,23 +1,48 @@
 <?php
+use Gt\Cipher\EncryptionFailureException;
+use Gt\Cipher\Message\DecryptionFailureException;
+
+require("vendor/autoload.php");
+
 $messageToTransmit = "Cipher test!";
 $sharedKey = random_bytes(SODIUM_CRYPTO_SECRETBOX_KEYBYTES);
 $iv = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
 
-$encryptedBytes = sodium_crypto_secretbox(
-	$messageToTransmit,
-	$iv,
-	$sharedKey
-);
+try {
+	$encryptedBytes = sodium_crypto_secretbox(
+		$messageToTransmit,
+		$iv,
+		$sharedKey
+	);
+}
+catch(Throwable $throwable) {
+	throw new EncryptionFailureException(
+		"Error encrypting cipher message",
+		previous: $throwable,
+	);
+}
 $cipher = base64_encode($encryptedBytes);
 
 echo "Shared key: ", base64_encode($sharedKey), PHP_EOL;
 echo "IV: ", base64_encode($iv), PHP_EOL;
 echo "Cipher: ", base64_encode($cipher), PHP_EOL;
 
-$decrypted = sodium_crypto_secretbox_open(
-	$encryptedBytes,
-	$iv,
-	$sharedKey,
-);
+try {
+	$decrypted = sodium_crypto_secretbox_open(
+		$encryptedBytes,
+		$iv,
+		$sharedKey,
+	);
+}
+catch(Throwable $throwable) {
+	throw new DecryptionFailureException(
+		"Error decrypting cipher message",
+		previous: $throwable,
+	);
+}
+
+if($decrypted === false) {
+	throw new DecryptionFailureException("Error decrypting cipher message");
+}
 
 echo "Decrypted: $decrypted", PHP_EOL;
diff --git a/src/CipherText.php b/src/CipherText.php
index 29e9318..1652656 100644
--- a/src/CipherText.php
+++ b/src/CipherText.php
@@ -4,6 +4,7 @@
 use Gt\Http\Uri;
 use Psr\Http\Message\UriInterface;
 use Stringable;
+use Throwable;
 
 class CipherText implements Stringable {
 	private string $bytes;
@@ -13,12 +14,19 @@ public function __construct(
 		private InitVector $iv,
 		private Key $key,
 	) {
-
-		$this->bytes = sodium_crypto_secretbox(
-			$data,
-			$this->iv->getBytes(),
-			$this->key->getBytes(),
-		);
+		try {
+			$this->bytes = sodium_crypto_secretbox(
+				$data,
+				$this->iv->getBytes(),
+				$this->key->getBytes(),
+			);
+		}
+		catch(Throwable $throwable) {
+			throw new EncryptionFailureException(
+				"Error encrypting cipher message",
+				previous: $throwable,
+			);
+		}
 	}
 
 	public function __toString():string {
diff --git a/src/EncryptedUri.php b/src/EncryptedUri.php
index 911d1c2..38abda8 100644
--- a/src/EncryptedUri.php
+++ b/src/EncryptedUri.php
@@ -1,10 +1,10 @@
 <?php
 namespace Gt\Cipher;
 
-use Gt\Cipher\Message\DecryptionFailureException;
 use Gt\Cipher\Message\PlainTextMessage;
 use Gt\Http\Uri;
 use Psr\Http\Message\UriInterface;
+use Throwable;
 
 class EncryptedUri {
 	private string $encryptedBytes;
@@ -39,13 +39,21 @@ public function __construct(
 	}
 
 	public function decryptMessage(Key $key):PlainTextMessage {
-		$decrypted = sodium_crypto_secretbox_open(
-			$this->encryptedBytes,
-			$this->iv->getBytes(),
-			$key->getBytes(),
-		);
+		try {
+			$decrypted = sodium_crypto_secretbox_open(
+				$this->encryptedBytes,
+				$this->iv->getBytes(),
+				$key->getBytes(),
+			);
+		}
+		catch(Throwable $throwable) {
+			throw new UriDecryptionFailureException(
+				"Error decrypting cipher URI",
+				previous: $throwable,
+			);
+		}
 		if($decrypted === false) {
-			throw new DecryptionFailureException("Error decrypting cipher message");
+			throw new UriDecryptionFailureException("Error decrypting cipher URI");
 		}
 		return new PlainTextMessage(
 			$decrypted,
diff --git a/src/EncryptionFailureException.php b/src/EncryptionFailureException.php
new file mode 100644
index 0000000..9abf0d6
--- /dev/null
+++ b/src/EncryptionFailureException.php
@@ -0,0 +1,4 @@
+<?php
+namespace Gt\Cipher;
+
+class EncryptionFailureException extends CipherException {}
diff --git a/src/Message/EncryptedMessage.php b/src/Message/EncryptedMessage.php
index 7d82eb2..dccf8bc 100644
--- a/src/Message/EncryptedMessage.php
+++ b/src/Message/EncryptedMessage.php
@@ -2,14 +2,23 @@
 namespace Gt\Cipher\Message;
 
 use Gt\Cipher\Key;
+use Throwable;
 
 class EncryptedMessage extends AbstractMessage {
 	public function decrypt(Key $key):PlainTextMessage {
-		$decrypted = sodium_crypto_secretbox_open(
-			base64_decode($this->data),
-			$this->iv->getBytes(),
-			$key->getBytes(),
-		);
+		try {
+			$decrypted = sodium_crypto_secretbox_open(
+				base64_decode($this->data),
+				$this->iv->getBytes(),
+				$key->getBytes(),
+			);
+		}
+		catch(Throwable $throwable) {
+			throw new DecryptionFailureException(
+				"Error decrypting cipher message",
+				previous: $throwable,
+			);
+		}
 		if($decrypted === false) {
 			throw new DecryptionFailureException("Error decrypting cipher message");
 		}
diff --git a/src/UriDecryptionFailureException.php b/src/UriDecryptionFailureException.php
new file mode 100644
index 0000000..056fa56
--- /dev/null
+++ b/src/UriDecryptionFailureException.php
@@ -0,0 +1,4 @@
+<?php
+namespace Gt\Cipher;
+
+class UriDecryptionFailureException extends CipherException {}
diff --git a/test/phpunit/CipherTextTest.php b/test/phpunit/CipherTextTest.php
index 5ad85cc..87e7bba 100644
--- a/test/phpunit/CipherTextTest.php
+++ b/test/phpunit/CipherTextTest.php
@@ -2,6 +2,7 @@
 namespace Gt\Cipher\Test;
 
 use Gt\Cipher\CipherText;
+use Gt\Cipher\EncryptionFailureException;
 use Gt\Cipher\InitVector;
 use Gt\Cipher\Key;
 use PHPUnit\Framework\TestCase;
@@ -51,4 +52,17 @@ public function testGetUri():void {
 		self::assertSame($baseUri, $uri->getScheme() . "://" . $uri->getAuthority());
 		self::assertSame(http_build_query($expectedQueryParts), $uri->getQuery());
 	}
+
+	public function testConstruct_wrapsSodiumFailure():void {
+		$data = "test data";
+		$iv = self::createMock(InitVector::class);
+		$iv->method("getBytes")
+			->willReturn(str_repeat("0", SODIUM_CRYPTO_SECRETBOX_NONCEBYTES));
+		$key = self::createMock(Key::class);
+		$key->method("getBytes")
+			->willReturn("bad");
+
+		self::expectException(EncryptionFailureException::class);
+		new CipherText($data, $iv, $key);
+	}
 }
diff --git a/test/phpunit/EncryptedUriTest.php b/test/phpunit/EncryptedUriTest.php
index 29f3b1d..801446d 100644
--- a/test/phpunit/EncryptedUriTest.php
+++ b/test/phpunit/EncryptedUriTest.php
@@ -4,8 +4,8 @@
 use Gt\Cipher\EncryptedUri;
 use Gt\Cipher\InitVector;
 use Gt\Cipher\Key;
-use Gt\Cipher\Message\DecryptionFailureException;
 use Gt\Cipher\MissingQueryStringException;
+use Gt\Cipher\UriDecryptionFailureException;
 use PHPUnit\Framework\TestCase;
 
 class EncryptedUriTest extends TestCase {
@@ -38,19 +38,38 @@ public function testConstruct_missingCipherValue():void {
 	}
 
 	public function testDecryptMessage_error():void {
-		$ivString = base64_encode(str_repeat("0", SODIUM_CRYPTO_SECRETBOX_NONCEBYTES));
+		$ivString = base64_encode(
+			str_repeat("0", SODIUM_CRYPTO_SECRETBOX_NONCEBYTES)
+		);
 		$uri = "https://example.com/test/?cipher=0000&iv=$ivString";
 		$sut = new EncryptedUri($uri);
 
 		$key = self::createMock(Key::class);
 		$key->method("getBytes")
 			->willReturn(str_repeat("0", SODIUM_CRYPTO_SECRETBOX_KEYBYTES));
-		self::expectException(DecryptionFailureException::class);
+		self::expectException(UriDecryptionFailureException::class);
+		$sut->decryptMessage($key);
+	}
+
+	public function testDecryptMessage_wrapsSodiumFailure():void {
+		$ivString = base64_encode(
+			str_repeat("0", SODIUM_CRYPTO_SECRETBOX_NONCEBYTES)
+		);
+		$uri = "https://example.com/test/?cipher=0000&iv=$ivString";
+		$sut = new EncryptedUri($uri);
+
+		$key = self::createMock(Key::class);
+		$key->method("getBytes")
+			->willReturn("bad");
+
+		self::expectException(UriDecryptionFailureException::class);
 		$sut->decryptMessage($key);
 	}
 
 	public function testDecryptMessage():void {
-		$uri = "https://example.com/?cipher=lmEClve%2FuhmK32ghM0%2BA%2FI%2Btysm00AL37YD6eg%3D%3D&iv=UVunn3laPVnK4CfHZuS2AnvJ1KfsPM1r";
+		$uri = "https://example.com/"
+			. "?cipher=lmEClve%2FuhmK32ghM0%2BA%2FI%2Btysm00AL37YD6eg%3D%3D"
+			. "&iv=UVunn3laPVnK4CfHZuS2AnvJ1KfsPM1r";
 		$sut = new EncryptedUri($uri);
 
 		$key = self::createMock(Key::class);
diff --git a/test/phpunit/Message/EncryptedMessageTest.php b/test/phpunit/Message/EncryptedMessageTest.php
index 7bf97df..57df7ac 100644
--- a/test/phpunit/Message/EncryptedMessageTest.php
+++ b/test/phpunit/Message/EncryptedMessageTest.php
@@ -41,4 +41,18 @@ public function testDecrypt_failure():void {
 		self::expectException(DecryptionFailureException::class);
 		$sut->decrypt($key);
 	}
+
+	public function testDecrypt_wrapsSodiumFailure():void {
+		$iv = self::createMock(InitVector::class);
+		$iv->method("getBytes")
+			->willReturn(str_repeat("0", SODIUM_CRYPTO_SECRETBOX_NONCEBYTES));
+		$sut = new EncryptedMessage("badly formed data", $iv);
+
+		$key = self::createMock(Key::class);
+		$key->method("getBytes")
+			->willReturn("bad");
+
+		self::expectException(DecryptionFailureException::class);
+		$sut->decrypt($key);
+	}
 }