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Vol. 1 · Ed. 2026
CyberGlossary
Entry № 612

iOS Keychain

iOS Keychain 是什么?

iOS KeychainApple's encrypted credential store on iOS, iPadOS, and macOS, backed by the Secure Enclave and graded by per-item accessibility classes that bind decryption to device unlock, passcode, biometric, or hardware-bound state.


The iOS Keychain is the OS-level encrypted credential and secret store used by iOS, iPadOS, macOS, watchOS, and tvOS, accessed via the SecItem* APIs. Items are encrypted with keys ultimately rooted in the Secure Enclave's hardware key and tied to the device's UID, so a Keychain database extracted off the device cannot be decrypted on different hardware. Each Keychain item carries an accessibility class that controls when it can be unlocked: `kSecAttrAccessibleWhenUnlocked`, `kSecAttrAccessibleAfterFirstUnlock`, the more restrictive `*ThisDeviceOnly` variants, and biometric- or passcode-gated `kSecAccessControl` constraints that require Face ID/Touch ID or the device passcode for each read. Common pitfalls in mobile AppSec include using too-permissive accessibility (e.g. `WhenUnlocked` without `ThisDeviceOnly`, which lets the item iCloud-sync across devices), storing high-entropy bearer tokens that don't need device-bound protection, and skipping `SecAccessControl` for credentials worth biometric-gating. Frida-based attacks on jailbroken devices can dump the Keychain unless items also carry hardware-bound access control. OWASP MASVS controls MSTG-CRYPTO and MSTG-STORAGE map directly to correct Keychain usage.

示例

  1. 01

    A banking app stores its OAuth refresh token with `kSecAttrAccessibleWhenUnlockedThisDeviceOnly` and `kSecAccessControlBiometryCurrentSet`, requiring fresh Face ID on every read.

  2. 02

    An audit finds an app storing API keys with `kSecAttrAccessibleAlways`, allowing extraction from a backup; the finding maps to MASVS MSTG-STORAGE-2.

常见问题

iOS Keychain 是什么?

Apple's encrypted credential store on iOS, iPadOS, and macOS, backed by the Secure Enclave and graded by per-item accessibility classes that bind decryption to device unlock, passcode, biometric, or hardware-bound state. 它属于网络安全的 移动安全 分类。

iOS Keychain 是什么意思?

Apple's encrypted credential store on iOS, iPadOS, and macOS, backed by the Secure Enclave and graded by per-item accessibility classes that bind decryption to device unlock, passcode, biometric, or hardware-bound state.

iOS Keychain 是如何工作的?

The iOS Keychain is the OS-level encrypted credential and secret store used by iOS, iPadOS, macOS, watchOS, and tvOS, accessed via the SecItem* APIs. Items are encrypted with keys ultimately rooted in the Secure Enclave's hardware key and tied to the device's UID, so a Keychain database extracted off the device cannot be decrypted on different hardware. Each Keychain item carries an accessibility class that controls when it can be unlocked: `kSecAttrAccessibleWhenUnlocked`, `kSecAttrAccessibleAfterFirstUnlock`, the more restrictive `*ThisDeviceOnly` variants, and biometric- or passcode-gated `kSecAccessControl` constraints that require Face ID/Touch ID or the device passcode for each read. Common pitfalls in mobile AppSec include using too-permissive accessibility (e.g. `WhenUnlocked` without `ThisDeviceOnly`, which lets the item iCloud-sync across devices), storing high-entropy bearer tokens that don't need device-bound protection, and skipping `SecAccessControl` for credentials worth biometric-gating. Frida-based attacks on jailbroken devices can dump the Keychain unless items also carry hardware-bound access control. OWASP MASVS controls MSTG-CRYPTO and MSTG-STORAGE map directly to correct Keychain usage.

如何防御 iOS Keychain?

针对 iOS Keychain 的防御通常结合技术控制与运营实践,详见上方完整定义。

iOS Keychain 还有哪些其他名称?

常见的别称包括: Apple Keychain, iOS Keychain Services。

相关术语

参见