[Android Q&A, Help & Troubleshooting] HpNoTiQ:
I think I've found the smali files to reverse engineer :

.class public Lcom/google/android/gms/common/GoogleSignatureVerifier;
.super Ljava/lang/Object;

# static fields
.field private static final zzaqd:Lcom/google/android/gms/common/GoogleSignatureVerifier;

# direct methods
.method static constructor <clinit>()V
.locals 1

new-instance v0, Lcom/google/android/gms/common/GoogleSignatureVerifier;

invoke-direct {v0}, Lcom/google/android/gms/common/GoogleSignatureVerifier;-><init>()V

sput-object v0, Lcom/google/android/gms/common/GoogleSignatureVerifier;->zzaqd:Lcom/google/android/gms/common/GoogleSignatureVerifier;

return-void
.end method

.method private constructor <init>()V
.locals 0

invoke-direct {p0}, Ljava/lang/Object;-><init>()V

return-void
.end method

.method public static getInstance()Lcom/google/android/gms/common/GoogleSignatureVerifier;
.locals 1

sget-object v0, Lcom/google/android/gms/common/GoogleSignatureVerifier;->zzaqd:Lcom/google/android/gms/common/GoogleSignatureVerifier;

return-object v0
.end method

.method private zzb(Landroid/content/pm/PackageInfo;Z)Z
.locals 5

const/4 v2, 0x1

const/4 v1, 0x0

iget-object v0, p1, Landroid/content/pm/PackageInfo;->signatures:[Landroid/content/pm/Signature;

array-length v0, v0

if-eq v0, v2, :cond_0

const-string/jumbo v0, "GoogleSignatureVerifier"

const-string/jumbo v2, "Package has more than one signature."

invoke-static {v0, v2}, Landroid/util/Log;->w(Ljava/lang/String;Ljava/lang/String;)I

move v0, v1

:goto_0
return v0

:cond_0
new-instance v3, Lcom/google/android/gms/common/zzc$zzb;

iget-object v0, p1, Landroid/content/pm/PackageInfo;->signatures:[Landroid/content/pm/Signature;

aget-object v0, v0, v1

invoke-virtual {v0}, Landroid/content/pm/Signature;->toByteArray()[B

move-result-object v0

invoke-direct {v3, v0}, Lcom/google/android/gms/common/zzc$zzb;-><init>([B)V

if-eqz p2, :cond_1

invoke-static {}, Lcom/google/android/gms/common/zzc;->zzpc()Ljava/util/Set;

move-result-object v0

:goto_1
invoke-interface {v0, v3}, Ljava/util/Set;->contains(Ljava/lang/Object;)Z

move-result v0

if-eqz v0, :cond_2

move v0, v2

goto :goto_0

:cond_1
invoke-static {}, Lcom/google/android/gms/common/zzc;->zzpd()Ljava/util/Set;

move-result-object v0

goto :goto_1

:cond_2
const-string/jumbo v0, "GoogleSignatureVerifier"

const/4 v2, 0x2

invoke-static {v0, v2}, Landroid/util/Log;->isLoggable(Ljava/lang/String;I)Z

move-result v0

if-eqz v0, :cond_3

const-string/jumbo v0, "GoogleSignatureVerifier"

new-instance v2, Ljava/lang/StringBuilder;

invoke-direct {v2}, Ljava/lang/StringBuilder;-><init>()V

const-string/jumbo v4, "Signature not valid. Found: \n"

invoke-virtual {v2, v4}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

move-result-object v2

invoke-virtual {v3}, Lcom/google/android/gms/common/zzc$zza;->getBytes()[B

move-result-object v3

invoke-static {v3, v1}, Landroid/util/Base64;->encodeToString([BI)Ljava/lang/String;

move-result-object v3

invoke-virtual {v2, v3}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

move-result-object v2

invoke-virtual {v2}, Ljava/lang/StringBuilder;->toString()Ljava/lang/String;

move-result-object v2

invoke-static {v0, v2}, Landroid/util/Log;->v(Ljava/lang/String;Ljava/lang/String;)I

:cond_3
move v0, v1

goto :goto_0
.end method

# virtual methods
.method public isPackageGoogleSigned(Landroid/content/pm/PackageManager;Landroid/content/pm/PackageInfo;)Z
.locals 3
.param p1, "packageManager" # Landroid/content/pm/PackageManager;
.param p2, "packageInfo" # Landroid/content/pm/PackageInfo;

.prologue
const/4 v2, 0x1

const/4 v0, 0x0

if-nez p2, :cond_1

:cond_0
:goto_0
return v0

:cond_1
invoke-static {p1}, Lcom/google/android/gms/common/GooglePlayServicesUtilLight;->honorsDebugCertificates(Landroid/content/pm/PackageManager;)Z

move-result v1

if-eqz v1, :cond_2

invoke-direct {p0, p2, v2}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->zzb(Landroid/content/pm/PackageInfo;Z)Z

move-result v0

goto :goto_0

:cond_2
invoke-direct {p0, p2, v0}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->zzb(Landroid/content/pm/PackageInfo;Z)Z

move-result v0

if-nez v0, :cond_0

invoke-direct {p0, p2, v2}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->zzb(Landroid/content/pm/PackageInfo;Z)Z

move-result v1

if-eqz v1, :cond_0

const-string/jumbo v1, "GoogleSignatureVerifier"

const-string/jumbo v2, "Test-keys aren\'t accepted on this build."

invoke-static {v1, v2}, Landroid/util/Log;->w(Ljava/lang/String;Ljava/lang/String;)I

goto :goto_0
.end method

.method public isPackageGoogleSigned(Landroid/content/pm/PackageManager;Ljava/lang/String;)Z
.locals 3
.param p1, "packageManager" # Landroid/content/pm/PackageManager;
.param p2, "callingPackage" # Ljava/lang/String;

.prologue
const/16 v0, 0x40

:try_start_0
invoke-virtual {p1, p2, v0}, Landroid/content/pm/PackageManager;->getPackageInfo(Ljava/lang/String;I)Landroid/content/pm/PackageInfo;
:try_end_0
.catch Landroid/content/pm/PackageManager$NameNotFoundException; {:try_start_0 .. :try_end_0} :catch_0

move-result-object v0

invoke-virtual {p0, p1, v0}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->isPackageGoogleSigned(Landroid/content/pm/PackageManager;Landroid/content/pm/PackageInfo;)Z

move-result v0

:goto_0
return v0

:catch_0
move-exception v0

const-string/jumbo v0, "GoogleSignatureVerifier"

const/4 v1, 0x3

invoke-static {v0, v1}, Landroid/util/Log;->isLoggable(Ljava/lang/String;I)Z

move-result v0

if-eqz v0, :cond_0

const-string/jumbo v0, "GoogleSignatureVerifier"

new-instance v1, Ljava/lang/StringBuilder;

invoke-direct {v1}, Ljava/lang/StringBuilder;-><init>()V

const-string/jumbo v2, "Package manager can\'t find package "

invoke-virtual {v1, v2}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

move-result-object v1

invoke-virtual {v1, p2}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

move-result-object v1

const-string/jumbo v2, ", defaulting to false"

invoke-virtual {v1, v2}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

move-result-object v1

invoke-virtual {v1}, Ljava/lang/StringBuilder;->toString()Ljava/lang/String;

move-result-object v1

invoke-static {v0, v1}, Landroid/util/Log;->d(Ljava/lang/String;Ljava/lang/String;)I

:cond_0
const/4 v0, 0x0

goto :goto_0
.end method

.method public isUidGoogleSigned(Landroid/content/pm/PackageManager;I)Z
.locals 5
.param p1, "packageManager" # Landroid/content/pm/PackageManager;
.param p2, "uid" # I

.prologue
const/4 v0, 0x0

invoke-virtual {p1, p2}, Landroid/content/pm/PackageManager;->getPackagesForUid(I)[Ljava/lang/String;

move-result-object v2

if-eqz v2, :cond_0

array-length v1, v2

if-nez v1, :cond_1

:cond_0
:goto_0
return v0

:cond_1
array-length v3, v2

move v1, v0

:goto_1
if-ge v1, v3, :cond_0

aget-object v4, v2, v1

invoke-virtual {p0, p1, v4}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->isPackageGoogleSigned(Landroid/content/pm/PackageManager;Ljava/lang/String;)Z

move-result v4

if-eqz v4, :cond_2

const/4 v0, 0x1

goto :goto_0

:cond_2
add-int/lit8 v1, v1, 0x1

goto :goto_1
.end method

.method public verifyPackageIsGoogleSigned(Landroid/content/pm/PackageManager;Ljava/lang/String;)V
.locals 3
.param p1, "packageManager" # Landroid/content/pm/PackageManager;
.param p2, "callingPackage" # Ljava/lang/String;
.annotation system Ldalvik/annotation/Throws;
value = {
Ljava/lang/SecurityException;
}
.end annotation

.prologue
invoke-virtual {p0, p1, p2}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->isPackageGoogleSigned(Landroid/content/pm/PackageManager;Ljava/lang/String;)Z

move-result v0

if-nez v0, :cond_0

new-instance v0, Ljava/lang/SecurityException;

new-instance v1, Ljava/lang/StringBuilder;

invoke-direct {v1}, Ljava/lang/StringBuilder;-><init>()V

const-string/jumbo v2, "Signature check failed for "

invoke-virtual {v1, v2}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

move-result-object v1

invoke-virtual {v1, p2}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

move-result-object v1

invoke-virtual {v1}, Ljava/lang/StringBuilder;->toString()Ljava/lang/String;

move-result-object v1

invoke-direct {v0, v1}, Ljava/lang/SecurityException;-><init>(Ljava/lang/String;)V

throw v0

:cond_0
return-void
.end method

.method public verifyUidIsGoogleSigned(Landroid/content/pm/PackageManager;I)V
.locals 2
.param p1, "packageManager" # Landroid/content/pm/PackageManager;
.param p2, "uid" # I
.annotation system Ldalvik/annotation/Throws;
value = {
Ljava/lang/SecurityException;
}
.end annotation

.prologue
if-nez p1, :cond_0

new-instance v0, Ljava/lang/SecurityException;

const-string/jumbo v1, "Unknown error: invalid Package Manager"

invoke-direct {v0, v1}, Ljava/lang/SecurityException;-><init>(Ljava/lang/String;)V

throw v0

:cond_0
invoke-virtual {p0, p1, p2}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->isUidGoogleSigned(Landroid/content/pm/PackageManager;I)Z

move-result v0

if-nez v0, :cond_1

new-instance v0, Ljava/lang/SecurityException;

const-string/jumbo v1, "Uid is not Google Signed"

invoke-direct {v0, v1}, Ljava/lang/SecurityException;-><init>(Ljava/lang/String;)V

throw v0

:cond_1
return-void
.end method

.method varargs zza(Landroid/content/pm/PackageInfo;[Lcom/google/android/gms/common/zzc$zza;)Lcom/google/android/gms/common/zzc$zza;
.locals 6

const/4 v2, 0x0

const/4 v1, 0x0

iget-object v0, p1, Landroid/content/pm/PackageInfo;->signatures:[Landroid/content/pm/Signature;

array-length v0, v0

const/4 v3, 0x1

if-eq v0, v3, :cond_0

const-string/jumbo v0, "GoogleSignatureVerifier"

const-string/jumbo v1, "Package has more than one signature."

invoke-static {v0, v1}, Landroid/util/Log;->w(Ljava/lang/String;Ljava/lang/String;)I

move-object v0, v2

:goto_0
return-object v0

:cond_0
new-instance v3, Lcom/google/android/gms/common/zzc$zzb;

iget-object v0, p1, Landroid/content/pm/PackageInfo;->signatures:[Landroid/content/pm/Signature;

aget-object v0, v0, v1

invoke-virtual {v0}, Landroid/content/pm/Signature;->toByteArray()[B

move-result-object v0

invoke-direct {v3, v0}, Lcom/google/android/gms/common/zzc$zzb;-><init>([B)V

move v0, v1

:goto_1
array-length v4, p2

if-ge v0, v4, :cond_2

aget-object v4, p2, v0

invoke-virtual {v4, v3}, Lcom/google/android/gms/common/zzc$zza;->equals(Ljava/lang/Object;)Z

move-result v4

if-eqz v4, :cond_1

aget-object v0, p2, v0

goto :goto_0

:cond_1
add-int/lit8 v0, v0, 0x1

goto :goto_1

:cond_2
const-string/jumbo v0, "GoogleSignatureVerifier"

const/4 v4, 0x2

invoke-static {v0, v4}, Landroid/util/Log;->isLoggable(Ljava/lang/String;I)Z

move-result v0

if-eqz v0, :cond_3

const-string/jumbo v0, "GoogleSignatureVerifier"

new-instance v4, Ljava/lang/StringBuilder;

invoke-direct {v4}, Ljava/lang/StringBuilder;-><init>()V

const-string/jumbo v5, "Signature not valid. Found: \n"

invoke-virtual {v4, v5}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

move-result-object v4

invoke-virtual {v3}, Lcom/google/android/gms/common/zzc$zza;->getBytes()[B

move-result-object v3

invoke-static {v3, v1}, Landroid/util/Base64;->encodeToString([BI)Ljava/lang/String;

move-result-object v1

invoke-virtual {v4, v1}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;

move-result-object v1

invoke-virtual {v1}, Ljava/lang/StringBuilder;->toString()Ljava/lang/String;

move-result-object v1

invoke-static {v0, v1}, Landroid/util/Log;->v(Ljava/lang/String;Ljava/lang/String;)I

:cond_3
move-object v0, v2

goto :goto_0
.end method

.method public zza(Landroid/content/pm/PackageInfo;Z)Z
.locals 4

const/4 v0, 0x1

const/4 v1, 0x0

if-eqz p1, :cond_1

iget-object v2, p1, Landroid/content/pm/PackageInfo;->signatures:[Landroid/content/pm/Signature;

if-eqz v2, :cond_1

if-eqz p2, :cond_0

sget-object v2, Lcom/google/android/gms/common/zzc$zzcm;->zzapV:[Lcom/google/android/gms/common/zzc$zza;

invoke-virtual {p0, p1, v2}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->zza(Landroid/content/pm/PackageInfo;[Lcom/google/android/gms/common/zzc$zza;)Lcom/google/android/gms/common/zzc$zza;

move-result-object v2

:goto_0
if-eqz v2, :cond_1

:goto_1
return v0

:cond_0
new-array v2, v0, [Lcom/google/android/gms/common/zzc$zza;

sget-object v3, Lcom/google/android/gms/common/zzc$zzcm;->zzapV:[Lcom/google/android/gms/common/zzc$zza;

aget-object v3, v3, v1

aput-object v3, v2, v1

invoke-virtual {p0, p1, v2}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->zza(Landroid/content/pm/PackageInfo;[Lcom/google/android/gms/common/zzc$zza;)Lcom/google/android/gms/common/zzc$zza;

move-result-object v2

goto :goto_0

:cond_1
move v0, v1

goto :goto_1
.end method

.method public zza(Landroid/content/pm/PackageManager;Landroid/content/pm/PackageInfo;)Z
.locals 3

const/4 v2, 0x1

const/4 v0, 0x0

if-nez p2, :cond_1

:cond_0
:goto_0
return v0

:cond_1
invoke-static {p1}, Lcom/google/android/gms/common/GooglePlayServicesUtilLight;->honorsDebugCertificates(Landroid/content/pm/PackageManager;)Z

move-result v1

if-eqz v1, :cond_2

invoke-virtual {p0, p2, v2}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->zza(Landroid/content/pm/PackageInfo;Z)Z

move-result v0

goto :goto_0

:cond_2
invoke-virtual {p0, p2, v0}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->zza(Landroid/content/pm/PackageInfo;Z)Z

move-result v0

if-nez v0, :cond_0

invoke-virtual {p0, p2, v2}, Lcom/google/android/gms/common/GoogleSignatureVerifier;->zza(Landroid/content/pm/PackageInfo;Z)Z

move-result v1

if-eqz v1, :cond_0

const-string/jumbo v1, "GoogleSignatureVerifier"

const-string/jumbo v2, "Test-keys aren\'t accepted on this build."

invoke-static {v1, v2}, Landroid/util/Log;->w(Ljava/lang/String;Ljava/lang/String;)I

goto :goto_0
.end method