diff --git a/Cargo.lock b/Cargo.lock
index 432943f..5d741aa 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -98,6 +98,21 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d0d27fb6b6f1e43147af148af49d49329413ba781aa0d5e10979831c210173b5"
 
+[[package]]
+name = "bit-set"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e11e16035ea35e4e5997b393eacbf6f63983188f7a2ad25bfb13465f5ad59de"
+dependencies = [
+ "bit-vec",
+]
+
+[[package]]
+name = "bit-vec"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "349f9b6a179ed607305526ca489b34ad0a41aed5f7980fa90eb03160b69598fb"
+
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -793,6 +808,18 @@ version = "2.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
 
+[[package]]
+name = "memoize"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb49e4361c7534fd1fd1d4a1da51b1bb4b254c5ebc519fc4e5dce578fd69f5d9"
+dependencies = [
+ "lazy_static 1.4.0",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "mime"
 version = "0.3.16"
@@ -1148,6 +1175,26 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "proptest"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e0d9cc07f18492d879586c92b485def06bc850da3118075cd45d50e9c95b0e5"
+dependencies = [
+ "bit-set",
+ "bitflags",
+ "byteorder",
+ "lazy_static 1.4.0",
+ "num-traits",
+ "quick-error 2.0.1",
+ "rand 0.8.4",
+ "rand_chacha 0.3.0",
+ "rand_xorshift",
+ "regex-syntax",
+ "rusty-fork",
+ "tempfile",
+]
+
 [[package]]
 name = "publicsuffix"
 version = "1.5.6"
@@ -1158,6 +1205,18 @@ dependencies = [
  "url",
 ]
 
+[[package]]
+name = "quick-error"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
+
+[[package]]
+name = "quick-error"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a993555f31e5a609f617c12db6250dedcac1b0a85076912c436e6fc9b2c8e6a3"
+
 [[package]]
 name = "quote"
 version = "1.0.9"
@@ -1286,6 +1345,15 @@ dependencies = [
  "rand_core 0.5.1",
 ]
 
+[[package]]
+name = "rand_xorshift"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d25bf25ec5ae4a3f1b92f929810509a2f53d7dca2f50b794ff57e3face536c8f"
+dependencies = [
+ "rand_core 0.6.2",
+]
+
 [[package]]
 name = "rdrand"
 version = "0.4.0"
@@ -1452,6 +1520,18 @@ dependencies = [
  "semver 0.11.0",
 ]
 
+[[package]]
+name = "rusty-fork"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb3dcc6e454c328bb824492db107ab7c0ae8fcffe4ad210136ef014458c1bc4f"
+dependencies = [
+ "fnv",
+ "quick-error 1.2.3",
+ "tempfile",
+ "wait-timeout",
+]
+
 [[package]]
 name = "ryu"
 version = "1.0.5"
@@ -1783,6 +1863,8 @@ dependencies = [
  "hmac-sha1",
  "lazy_static 1.4.0",
  "log",
+ "memoize",
+ "proptest",
  "rand 0.8.4",
  "regex",
  "reqwest",
@@ -2210,6 +2292,15 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
 
+[[package]]
+name = "wait-timeout"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f200f5b12eb75f8c1ed65abd4b2db8a6e1b138a20de009dacee265a2498f3f6"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "want"
 version = "0.3.0"
diff --git a/Cargo.toml b/Cargo.toml
index 2e1daea..d85bacd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -38,6 +38,8 @@ ring = "0.16.20"
 aes = "0.7.4"
 block-modes = "0.8.1"
 thiserror = "1.0.26"
+memoize = "0.1.9"
 
 [dev-dependencies]
 tempdir = "0.3"
+proptest = "1"
diff --git a/src/encryption.rs b/src/encryption.rs
index f31a343..07fbdfc 100644
--- a/src/encryption.rs
+++ b/src/encryption.rs
@@ -182,6 +182,7 @@ impl From<std::io::Error> for EntryEncryptionError {
 #[cfg(test)]
 mod tests {
 	use super::*;
+	use proptest::prelude::*;
 
 	/// This test ensures compatibility with SteamDesktopAuthenticator and with previous versions of steamguard-cli
 	#[test]
@@ -202,4 +203,45 @@ mod tests {
 				.as_slice()
 		);
 	}
+
+	#[test]
+	fn test_ensure_encryption_symmetric() -> anyhow::Result<()> {
+		let passkey = "password";
+		let params = EntryEncryptionParams::generate();
+		let orig = "{{tactical glizzy}}".as_bytes().to_vec();
+		let encrypted =
+			LegacySdaCompatible::encrypt(&passkey.clone().into(), &params, orig.clone()).unwrap();
+		let result = LegacySdaCompatible::decrypt(&passkey.into(), &params, encrypted).unwrap();
+		assert_eq!(orig, result.to_vec());
+		return Ok(());
+	}
+
+	prop_compose! {
+		/// An insecure but reproducible strategy for generating encryption params.
+		fn encryption_params()(salt in any::<[u8; SALT_LENGTH]>(), iv in any::<[u8; IV_LENGTH]>()) -> EntryEncryptionParams {
+			EntryEncryptionParams {
+				salt: base64::encode(&salt),
+				iv: base64::encode(&iv),
+				scheme: EncryptionScheme::LegacySdaCompatible,
+			}
+		}
+	}
+
+	// proptest! {
+	// 	#[test]
+	// 	fn ensure_encryption_symmetric(
+	// 		passkey in ".{1,}",
+	// 		params in encryption_params(),
+	// 		data in any::<Vec<u8>>(),
+	// 	) {
+	// 		prop_assume!(data.len() >= 2);
+	// 		let mut orig = data;
+	// 		orig[0] = '{' as u8;
+	// 		let n = orig.len() - 1;
+	// 		orig[n] = '}' as u8;
+	// 		let encrypted = LegacySdaCompatible::encrypt(&passkey.clone().into(), &params, orig.clone()).unwrap();
+	// 		let result = LegacySdaCompatible::decrypt(&passkey.into(), &params, encrypted).unwrap();
+	// 		prop_assert_eq!(orig, result.to_vec());
+	// 	}
+	// }
 }
diff --git a/src/main.rs b/src/main.rs
index c4f3156..d6856bb 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -18,6 +18,8 @@ extern crate lazy_static;
 extern crate anyhow;
 extern crate base64;
 extern crate dirs;
+#[cfg(test)]
+extern crate proptest;
 extern crate ring;
 mod accountmanager;
 mod demos;