diff --git a/crypto/src/encdec/tests.rs b/crypto/src/encdec/tests.rs
index 1258ace1..0d3fd5ef 100644
--- a/crypto/src/encdec/tests.rs
+++ b/crypto/src/encdec/tests.rs
@@ -1,14 +1,299 @@
 use crate::{decrypt_data, encrypt_data};
 
 const PASSWORD: &[u8] = "test_password".as_bytes();
+const LONG_PASSWORD: &[u8] = "very_long_password_with_many_characters_for_testing_purposes_123456789".as_bytes();
+const EMPTY_PASSWORD: &[u8] = b"";
 
 #[test_case::test_case("hello world".as_bytes())]
 #[test_case::test_case(&[])]
 #[test_case::test_case(&[1, 2, 3])]
 #[test_case::test_case(&[3, 2, 1])]
-fn test(input: &[u8]) -> Result<(), crate::Error> {
+fn test_basic_encrypt_decrypt_roundtrip(input: &[u8]) -> Result<(), crate::Error> {
     let encrypted = encrypt_data(PASSWORD, input)?;
     let decrypted = decrypt_data(PASSWORD, &encrypted)?;
     assert_eq!(input, decrypted, "input is not equal output");
     Ok(())
 }
+
+#[test]
+fn test_encrypt_decrypt_with_different_passwords() -> Result<(), crate::Error> {
+    let data = b"sensitive data";
+    let password1 = b"password1";
+    let password2 = b"password2";
+
+    let encrypted = encrypt_data(password1, data)?;
+
+    // Decrypting with correct password should work
+    let decrypted = decrypt_data(password1, &encrypted)?;
+    assert_eq!(data, decrypted.as_slice());
+
+    // Decrypting with wrong password should fail
+    let result = decrypt_data(password2, &encrypted);
+    assert!(result.is_err(), "Decryption with wrong password should fail");
+
+    Ok(())
+}
+
+#[test]
+fn test_encrypt_decrypt_empty_data() -> Result<(), crate::Error> {
+    let empty_data = b"";
+    let encrypted = encrypt_data(PASSWORD, empty_data)?;
+    let decrypted = decrypt_data(PASSWORD, &encrypted)?;
+    assert_eq!(empty_data, decrypted.as_slice());
+    Ok(())
+}
+
+#[test]
+fn test_encrypt_decrypt_large_data() -> Result<(), crate::Error> {
+    // Test with 1MB of data
+    let large_data = vec![0xAB; 1024 * 1024];
+    let encrypted = encrypt_data(PASSWORD, &large_data)?;
+    let decrypted = decrypt_data(PASSWORD, &encrypted)?;
+    assert_eq!(large_data, decrypted);
+    Ok(())
+}
+
+#[test]
+fn test_encrypt_decrypt_with_empty_password() -> Result<(), crate::Error> {
+    let data = b"test data";
+    let encrypted = encrypt_data(EMPTY_PASSWORD, data)?;
+    let decrypted = decrypt_data(EMPTY_PASSWORD, &encrypted)?;
+    assert_eq!(data, decrypted.as_slice());
+    Ok(())
+}
+
+#[test]
+fn test_encrypt_decrypt_with_long_password() -> Result<(), crate::Error> {
+    let data = b"test data with long password";
+    let encrypted = encrypt_data(LONG_PASSWORD, data)?;
+    let decrypted = decrypt_data(LONG_PASSWORD, &encrypted)?;
+    assert_eq!(data, decrypted.as_slice());
+    Ok(())
+}
+
+#[test]
+fn test_encrypt_decrypt_binary_data() -> Result<(), crate::Error> {
+    // Test with various binary patterns
+    let binary_patterns = [
+        vec![0x00; 100],                    // All zeros
+        vec![0xFF; 100],                    // All ones
+        (0..=255u8).cycle().take(1000).collect::<Vec<u8>>(), // Sequential pattern
+        vec![0xAA, 0x55].repeat(500),       // Alternating pattern
+    ];
+
+    for pattern in &binary_patterns {
+        let encrypted = encrypt_data(PASSWORD, pattern)?;
+        let decrypted = decrypt_data(PASSWORD, &encrypted)?;
+        assert_eq!(pattern, &decrypted, "Binary pattern mismatch");
+    }
+    Ok(())
+}
+
+#[test]
+fn test_encrypt_decrypt_unicode_data() -> Result<(), crate::Error> {
+    let unicode_strings = [
+        "Hello, 世界! 🌍",
+        "Тест на русском языке",
+        "العربية اختبار",
+        "🚀🔐💻🌟⭐",
+        "Mixed: ASCII + 中文 + العربية + 🎉",
+    ];
+
+    for text in &unicode_strings {
+        let data = text.as_bytes();
+        let encrypted = encrypt_data(PASSWORD, data)?;
+        let decrypted = decrypt_data(PASSWORD, &encrypted)?;
+        assert_eq!(data, decrypted.as_slice(), "Unicode data mismatch for: {}", text);
+    }
+    Ok(())
+}
+
+#[test]
+fn test_decrypt_with_corrupted_data() {
+    let data = b"test data";
+    let encrypted = encrypt_data(PASSWORD, data).expect("Encryption should succeed");
+
+    // Test various corruption scenarios
+    let corruption_tests = [
+        (0, "Corrupt first byte"),
+        (encrypted.len() - 1, "Corrupt last byte"),
+        (encrypted.len() / 2, "Corrupt middle byte"),
+    ];
+
+    for (corrupt_index, description) in &corruption_tests {
+        let mut corrupted = encrypted.clone();
+        corrupted[*corrupt_index] ^= 0xFF; // Flip all bits
+
+        let result = decrypt_data(PASSWORD, &corrupted);
+        assert!(result.is_err(), "{} should cause decryption to fail", description);
+    }
+}
+
+#[test]
+fn test_decrypt_with_truncated_data() {
+    let data = b"test data for truncation";
+    let encrypted = encrypt_data(PASSWORD, data).expect("Encryption should succeed");
+
+    // Test truncation at various lengths
+    let truncation_lengths = [
+        0,                          // Empty data
+        10,                         // Very short
+        32,                         // Salt length
+        44,                         // Just before nonce
+        encrypted.len() - 1,        // Missing last byte
+    ];
+
+    for &length in &truncation_lengths {
+        let truncated = &encrypted[..length.min(encrypted.len())];
+        let result = decrypt_data(PASSWORD, truncated);
+        assert!(result.is_err(), "Truncated data (length {}) should cause decryption to fail", length);
+    }
+}
+
+#[test]
+fn test_decrypt_with_invalid_header() {
+    let data = b"test data";
+    let mut encrypted = encrypt_data(PASSWORD, data).expect("Encryption should succeed");
+
+    // Corrupt the algorithm ID (byte 32)
+    if encrypted.len() > 32 {
+        encrypted[32] = 0xFF; // Invalid algorithm ID
+        let result = decrypt_data(PASSWORD, &encrypted);
+        assert!(result.is_err(), "Invalid algorithm ID should cause decryption to fail");
+    }
+}
+
+#[test]
+fn test_encryption_produces_different_outputs() -> Result<(), crate::Error> {
+    let data = b"same data";
+
+    // Encrypt the same data multiple times
+    let encrypted1 = encrypt_data(PASSWORD, data)?;
+    let encrypted2 = encrypt_data(PASSWORD, data)?;
+
+    // Encrypted outputs should be different due to random salt and nonce
+    assert_ne!(encrypted1, encrypted2, "Encryption should produce different outputs for same input");
+
+    // But both should decrypt to the same original data
+    let decrypted1 = decrypt_data(PASSWORD, &encrypted1)?;
+    let decrypted2 = decrypt_data(PASSWORD, &encrypted2)?;
+    assert_eq!(decrypted1, decrypted2);
+    assert_eq!(data, decrypted1.as_slice());
+
+    Ok(())
+}
+
+#[test]
+fn test_encrypted_data_structure() -> Result<(), crate::Error> {
+    let data = b"test data";
+    let encrypted = encrypt_data(PASSWORD, data)?;
+
+    // Encrypted data should be longer than original (due to salt, nonce, tag)
+    assert!(encrypted.len() > data.len(), "Encrypted data should be longer than original");
+
+    // Should have at least: 32 bytes salt + 1 byte ID + 12 bytes nonce + data + 16 bytes tag
+    let min_expected_length = 32 + 1 + 12 + data.len() + 16;
+    assert!(encrypted.len() >= min_expected_length,
+        "Encrypted data length {} should be at least {}", encrypted.len(), min_expected_length);
+
+    Ok(())
+}
+
+#[test]
+fn test_password_variations() -> Result<(), crate::Error> {
+    let data = b"test data";
+
+    let password_variations = [
+        b"a".as_slice(),                    // Single character
+        b"12345".as_slice(),                // Numeric
+        b"!@#$%^&*()".as_slice(),          // Special characters
+        b"\x00\x01\x02\x03".as_slice(),    // Binary password
+        "密码测试".as_bytes(),               // Unicode password
+        &[0xFF; 64],                        // Long binary password
+    ];
+
+    for password in &password_variations {
+        let encrypted = encrypt_data(password, data)?;
+        let decrypted = decrypt_data(password, &encrypted)?;
+        assert_eq!(data, decrypted.as_slice(), "Failed with password: {:?}", password);
+    }
+
+    Ok(())
+}
+
+#[test]
+fn test_deterministic_with_same_salt_and_nonce() {
+    // Note: This test is more for understanding the behavior
+    // In real implementation, salt and nonce should be random
+    let data = b"test data";
+
+    let encrypted1 = encrypt_data(PASSWORD, data).expect("Encryption should succeed");
+    let encrypted2 = encrypt_data(PASSWORD, data).expect("Encryption should succeed");
+
+    // Due to random salt and nonce, outputs should be different
+    assert_ne!(encrypted1, encrypted2, "Encryption should use random salt/nonce");
+}
+
+#[test]
+fn test_cross_platform_compatibility() -> Result<(), crate::Error> {
+    // Test data that might behave differently on different platforms
+    let test_cases = [
+        vec![0x00, 0x01, 0x02, 0x03],      // Low values
+        vec![0xFC, 0xFD, 0xFE, 0xFF],      // High values
+        (0..256u16).map(|x| (x % 256) as u8).collect::<Vec<u8>>(), // Full byte range
+    ];
+
+    for test_data in &test_cases {
+        let encrypted = encrypt_data(PASSWORD, test_data)?;
+        let decrypted = decrypt_data(PASSWORD, &encrypted)?;
+        assert_eq!(test_data, &decrypted, "Cross-platform compatibility failed");
+    }
+
+    Ok(())
+}
+
+#[test]
+fn test_memory_safety_with_large_passwords() -> Result<(), crate::Error> {
+    let data = b"test data";
+
+    // Test with very large passwords
+    let large_passwords = [
+        vec![b'a'; 1024],           // 1KB password
+        vec![b'x'; 10 * 1024],      // 10KB password
+        (0..=255u8).cycle().take(5000).collect::<Vec<u8>>(), // 5KB varied password
+    ];
+
+    for password in &large_passwords {
+        let encrypted = encrypt_data(password, data)?;
+        let decrypted = decrypt_data(password, &encrypted)?;
+        assert_eq!(data, decrypted.as_slice(), "Failed with large password of size {}", password.len());
+    }
+
+    Ok(())
+}
+
+#[test]
+fn test_concurrent_encryption_safety() -> Result<(), crate::Error> {
+    use std::sync::Arc;
+    use std::thread;
+
+    let data = Arc::new(b"concurrent test data".to_vec());
+    let password = Arc::new(b"concurrent_password".to_vec());
+
+    let handles: Vec<_> = (0..10).map(|i| {
+        let data = Arc::clone(&data);
+        let password = Arc::clone(&password);
+
+        thread::spawn(move || {
+            let encrypted = encrypt_data(&password, &data).expect("Encryption should succeed");
+            let decrypted = decrypt_data(&password, &encrypted).expect("Decryption should succeed");
+            assert_eq!(**data, decrypted, "Thread {} failed", i);
+        })
+    }).collect();
+
+    for handle in handles {
+        handle.join().expect("Thread should complete successfully");
+    }
+
+    Ok(())
+}
diff --git a/crypto/src/jwt/tests.rs b/crypto/src/jwt/tests.rs
index 627e8802..04cd0222 100644
--- a/crypto/src/jwt/tests.rs
+++ b/crypto/src/jwt/tests.rs
@@ -1,19 +1,337 @@
 use time::OffsetDateTime;
+use serde_json::json;
 
 use super::{decode::decode, encode::encode};
 
 #[test]
-fn test() {
-    let claims = serde_json::json!({
+fn test_jwt_encode_decode_basic() {
+    let claims = json!({
         "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
-        "aaa": 1,
-        "bbb": "bbb"
+        "sub": "user123",
+        "iat": OffsetDateTime::now_utc().unix_timestamp(),
+        "role": "admin"
     });
 
-    let jwt_token = encode(b"aaaa", &claims).unwrap_or_default();
-    let new_claims = match decode(&jwt_token, b"aaaa") {
-        Ok(res) => Some(res.claims),
-        Err(_errr) => None,
-    };
-    assert_eq!(new_claims, Some(claims));
+    let secret = b"test_secret_key";
+    let jwt_token = encode(secret, &claims).expect("Failed to encode JWT");
+
+    let decoded = decode(&jwt_token, secret).expect("Failed to decode JWT");
+    assert_eq!(decoded.claims, claims);
+}
+
+#[test]
+fn test_jwt_encode_decode_with_complex_claims() {
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 3600,
+        "sub": "user456",
+        "iat": OffsetDateTime::now_utc().unix_timestamp(),
+        "permissions": ["read", "write", "delete"],
+        "metadata": {
+            "department": "engineering",
+            "level": 5,
+            "active": true
+        },
+        "custom_field": null
+    });
+
+    let secret = b"complex_secret_key_123";
+    let jwt_token = encode(secret, &claims).expect("Failed to encode complex JWT");
+
+    let decoded = decode(&jwt_token, secret).expect("Failed to decode complex JWT");
+    assert_eq!(decoded.claims, claims);
+}
+
+#[test]
+fn test_jwt_decode_with_wrong_secret() {
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
+        "sub": "user123"
+    });
+
+    let correct_secret = b"correct_secret";
+    let wrong_secret = b"wrong_secret";
+
+    let jwt_token = encode(correct_secret, &claims).expect("Failed to encode JWT");
+
+    // Decoding with wrong secret should fail
+    let result = decode(&jwt_token, wrong_secret);
+    assert!(result.is_err(), "Decoding with wrong secret should fail");
+}
+
+#[test]
+fn test_jwt_decode_invalid_token_format() {
+    let secret = b"test_secret";
+
+    // Test various invalid token formats
+    let invalid_tokens = [
+        "",                           // Empty token
+        "invalid",                    // Not a JWT format
+        "header.payload",             // Missing signature
+        "header.payload.signature.extra", // Too many parts
+        "invalid.header.signature",   // Invalid base64
+        "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.invalid.signature", // Invalid payload
+    ];
+
+    for invalid_token in &invalid_tokens {
+        let result = decode(invalid_token, secret);
+        assert!(result.is_err(), "Invalid token '{}' should fail to decode", invalid_token);
+    }
+}
+
+#[test]
+fn test_jwt_with_expired_token() {
+    let expired_claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() - 1000, // Expired 1000 seconds ago
+        "sub": "user123",
+        "iat": OffsetDateTime::now_utc().unix_timestamp() - 2000
+    });
+
+    let secret = b"test_secret";
+    let jwt_token = encode(secret, &expired_claims).expect("Failed to encode expired JWT");
+
+    // Decoding expired token should fail
+    let result = decode(&jwt_token, secret);
+    assert!(result.is_err(), "Expired token should fail to decode");
+}
+
+#[test]
+fn test_jwt_with_future_issued_at() {
+    let future_claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 3600,
+        "sub": "user123",
+        "iat": OffsetDateTime::now_utc().unix_timestamp() + 1000 // Issued in future
+    });
+
+    let secret = b"test_secret";
+    let jwt_token = encode(secret, &future_claims).expect("Failed to encode future JWT");
+
+    // Note: The current JWT implementation may not validate iat by default
+    // This test documents the current behavior - future iat tokens may still decode successfully
+    let result = decode(&jwt_token, secret);
+    // For now, we just verify the token can be decoded, but in a production system
+    // you might want to add custom validation for iat claims
+    assert!(result.is_ok(), "Token decoding should succeed, but iat validation should be handled separately");
+}
+
+#[test]
+fn test_jwt_with_empty_claims() {
+    let empty_claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000, // Add required exp claim
+    });
+    let secret = b"test_secret";
+
+    let jwt_token = encode(secret, &empty_claims).expect("Failed to encode empty claims JWT");
+    let decoded = decode(&jwt_token, secret).expect("Failed to decode empty claims JWT");
+
+    assert_eq!(decoded.claims, empty_claims);
+}
+
+#[test]
+fn test_jwt_with_different_secret_lengths() {
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
+        "sub": "user123"
+    });
+
+    // Test with various secret lengths
+    let secrets = [
+        b"a".as_slice(),                    // Very short
+        b"short_key".as_slice(),            // Short
+        b"medium_length_secret_key".as_slice(), // Medium
+        b"very_long_secret_key_with_many_characters_for_testing_purposes".as_slice(), // Long
+    ];
+
+    for secret in &secrets {
+        let jwt_token = encode(secret, &claims)
+            .expect(&format!("Failed to encode JWT with secret length {}", secret.len()));
+
+        let decoded = decode(&jwt_token, secret)
+            .expect(&format!("Failed to decode JWT with secret length {}", secret.len()));
+
+        assert_eq!(decoded.claims, claims);
+    }
+}
+
+#[test]
+fn test_jwt_with_special_characters_in_claims() {
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
+        "sub": "user@example.com",
+        "name": "John Doe",
+        "description": "User with special chars: !@#$%^&*()_+-=[]{}|;':\",./<>?",
+        "unicode": "测试用户 🚀 émojis",
+        "newlines": "line1\nline2\r\nline3",
+        "quotes": "He said \"Hello\" and she replied 'Hi'"
+    });
+
+    let secret = b"test_secret";
+    let jwt_token = encode(secret, &claims).expect("Failed to encode JWT with special characters");
+
+    let decoded = decode(&jwt_token, secret).expect("Failed to decode JWT with special characters");
+    assert_eq!(decoded.claims, claims);
+}
+
+#[test]
+fn test_jwt_with_large_payload() {
+    // Create a large payload to test size limits
+    let large_data = "x".repeat(10000); // 10KB of data
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
+        "sub": "user123",
+        "large_field": large_data
+    });
+
+    let secret = b"test_secret";
+    let jwt_token = encode(secret, &claims).expect("Failed to encode large JWT");
+
+    let decoded = decode(&jwt_token, secret).expect("Failed to decode large JWT");
+    assert_eq!(decoded.claims, claims);
+}
+
+#[test]
+fn test_jwt_token_structure() {
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
+        "sub": "user123"
+    });
+
+    let secret = b"test_secret";
+    let jwt_token = encode(secret, &claims).expect("Failed to encode JWT");
+
+    // JWT should have exactly 3 parts separated by dots
+    let parts: Vec<&str> = jwt_token.split('.').collect();
+    assert_eq!(parts.len(), 3, "JWT should have exactly 3 parts");
+
+    // Each part should be non-empty
+    for (i, part) in parts.iter().enumerate() {
+        assert!(!part.is_empty(), "JWT part {} should not be empty", i);
+    }
+}
+
+#[test]
+fn test_jwt_deterministic_encoding() {
+    let claims = json!({
+        "exp": 1234567890,  // Fixed timestamp for deterministic test
+        "sub": "user123",
+        "iat": 1234567800
+    });
+
+    let secret = b"test_secret";
+
+    // Encode the same claims multiple times
+    let token1 = encode(secret, &claims).expect("Failed to encode JWT 1");
+    let token2 = encode(secret, &claims).expect("Failed to encode JWT 2");
+
+    // Tokens should be identical for same input
+    assert_eq!(token1, token2, "JWT encoding should be deterministic");
+}
+
+#[test]
+fn test_jwt_cross_compatibility() {
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
+        "sub": "user123"
+    });
+
+    let secret1 = b"secret1";
+    let secret2 = b"secret2";
+
+    // Encode with secret1
+    let token1 = encode(secret1, &claims).expect("Failed to encode with secret1");
+
+    // Decode with secret1 should work
+    let decoded1 = decode(&token1, secret1).expect("Failed to decode with correct secret");
+    assert_eq!(decoded1.claims, claims);
+
+    // Decode with secret2 should fail
+    let result2 = decode(&token1, secret2);
+    assert!(result2.is_err(), "Decoding with different secret should fail");
+}
+
+#[test]
+fn test_jwt_header_algorithm() {
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
+        "sub": "user123"
+    });
+
+    let secret = b"test_secret";
+    let jwt_token = encode(secret, &claims).expect("Failed to encode JWT");
+
+    let decoded = decode(&jwt_token, secret).expect("Failed to decode JWT");
+
+    // Verify the algorithm in header is HS512
+    assert_eq!(decoded.header.alg, jsonwebtoken::Algorithm::HS512);
+    assert_eq!(decoded.header.typ, Some("JWT".to_string()));
+}
+
+#[test]
+fn test_jwt_claims_validation() {
+    let now = OffsetDateTime::now_utc().unix_timestamp();
+
+    let valid_claims = json!({
+        "exp": now + 3600,  // Expires in 1 hour
+        "iat": now - 60,    // Issued 1 minute ago
+        "nbf": now - 30,    // Not before 30 seconds ago
+        "sub": "user123"
+    });
+
+    let secret = b"test_secret";
+    let jwt_token = encode(secret, &valid_claims).expect("Failed to encode valid JWT");
+
+    let decoded = decode(&jwt_token, secret).expect("Failed to decode valid JWT");
+    assert_eq!(decoded.claims, valid_claims);
+}
+
+#[test]
+fn test_jwt_with_numeric_claims() {
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
+        "sub": "user123",
+        "age": 25,
+        "score": 95.5,
+        "count": 0,
+        "negative": -10
+    });
+
+    let secret = b"test_secret";
+    let jwt_token = encode(secret, &claims).expect("Failed to encode numeric JWT");
+
+    let decoded = decode(&jwt_token, secret).expect("Failed to decode numeric JWT");
+    assert_eq!(decoded.claims, claims);
+}
+
+#[test]
+fn test_jwt_with_boolean_claims() {
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
+        "sub": "user123",
+        "is_admin": true,
+        "is_active": false,
+        "email_verified": true
+    });
+
+    let secret = b"test_secret";
+    let jwt_token = encode(secret, &claims).expect("Failed to encode boolean JWT");
+
+    let decoded = decode(&jwt_token, secret).expect("Failed to decode boolean JWT");
+    assert_eq!(decoded.claims, claims);
+}
+
+#[test]
+fn test_jwt_with_array_claims() {
+    let claims = json!({
+        "exp": OffsetDateTime::now_utc().unix_timestamp() + 1000,
+        "sub": "user123",
+        "roles": ["admin", "user", "moderator"],
+        "permissions": [1, 2, 3, 4, 5],
+        "tags": [],
+        "mixed_array": ["string", 123, true, null]
+    });
+
+    let secret = b"test_secret";
+    let jwt_token = encode(secret, &claims).expect("Failed to encode array JWT");
+
+    let decoded = decode(&jwt_token, secret).expect("Failed to decode array JWT");
+    assert_eq!(decoded.claims, claims);
 }