KO | EN

GitLite

Minimalist Open Source Repository Search Engine

gitlite — search

#typescript #ai-agents #cli #claude-code #codex #developer-tools #ai #dsh-plugin #ai-agent #mcp #deepseek-harness #windows

gsalogin

★ 81 Open GitHub ↗

iOS/macOS login algorithm gsa

// repository documentation

Was this content helpful?

★ 0 (0 ratings)

# gsalogin
  apple account login srp-6a protocol

The following is a description of SRP-6 and 6a, the latest versions of SRP:

N    A large safe prime (N = 2q+1, where q is prime)
	       All arithmetic is done modulo N.
	  g    A generator modulo N
	  k    Multiplier parameter (k = H(N, g) in SRP-6a, k = 3 for legacy SRP-6)
	  s    User's salt
	  I    Username
	  p    Cleartext Password
	  H()  One-way hash function
	  ^    (Modular) Exponentiation
	  u    Random scrambling parameter
	  a,b  Secret ephemeral values
	  A,B  Public ephemeral values
	  x    Private key (derived from p and s)
	  v    Password verifier
	The host stores passwords using the following formula:
	  x = H(s, p)               (s is chosen randomly)
	  v = g^x                   (computes password verifier)
	The host then keeps {I, s, v} in its password database. The authentication protocol itself goes as follows:
	User -> Host:  I, A = g^a                  (identifies self, a = random number)
	Host -> User:  s, B = kv + g^b             (sends salt, b = random number)

Both:  u = H(A, B)

User:  x = H(s, p)                 (user enters password)
        User:  S = (B - kg^x) ^ (a + ux)   (computes session key)
        User:  K = H(S)

Host:  S = (Av^u) ^ b              (computes session key)
        Host:  K = H(S)
# Diff between standard and apple
	 u = H(A,B)  ==> u = sha256(A+B) 
	 k = H(N,g)  ==>  k = sha256(N+g)  N is 256byte big-endian order,  g is256 byte big-endian order bytes
	 x = H(s,p)  ==> apple's s => H(":"+P) without username
	 P password field P = hmac(pass, salt, iter) where pass = sha256(password_text)
# Apple M1 field 
	i = H(g) xor H(N)
	M1 = H(i) + H(I) + H(salt) + H(A) + H(B) + H(K) 
	+  ==>  sha256_update
 # x-apple-i-md pairs
 	It's apple device time based token pairs. the time base is updated every 30 seconds, aligned to the
 	half-minute boundary. the token ticket is stored on akd-container-data//Library/adi.pb
  	This file can store one or more  accounts device token ticket. when a device is newly active the akd process
   	exchange an apple signed binary blob. the ticket is based on adid process but the code is heavily
	obfuscated, so it's hard to know what happened in the adid.
	The adi.pb storage rules vary slightly across platforms, but overall the file is encrypted, and the core
	dependency is the input device information.
	Reversing this part of the algorithm is extremely difficult: so far, no one has published a human-readable
	reconstruction of the algorithm after stripping its OLLVM obfuscation.
	If you are interested in this part, refer to the mwpcheung/akikit project, which provides a stable and
	general-purpose interface you can use. By leveraging CPU virtualization technology, akikit can emulate the
	computation across different platforms (iOS, macOS, Linux-Android, Windows) with stable, high-performance
	results, at around 300ms per computation. The latency mainly comes from loading and parsing the binary
	file, the instruction warm-up, and the extremely heavy computation of the OLLVM-obfuscated code.

gsalogin

Explore Similar Repositories

Was this content helpful?

Recent Feedback

Download README