ORDER GRANTING MOTION FOR DE NOVO REVIEW AND HOLDING THAT GOVERNMENT MAY WITHHOLD MATERIALS

This is a long-standing FOIA case involving a convicted LSD manufacturer’s search for information about a confidential informant who testified against him. The particular motion that is pending, however—Defendant United States Department of Justice’s Second Motion for De Novo Determination of Dispositive Matter Referred to Magistrate Judge, 2d Mot. for De Novo Review (dkt. 260)—involves information that the parties agree is already known, because a confidential informant has already disclosed it. The motion challenges an order by Magistrate Judge Na-thanael M. Cousins holding that none of the government’s claimed FOIA exemptions apply, and ordering released the three categories of materials that Plaintiff William L. Pickard currently seeks: (1) confidential informant Gordon Skinner’s name, (2) information Skinner has voluntarily disclosed to the public, and (3) Skinner’s NADDIS number.1 See generally Order to Release (dkt. 243).

*1083That Pickard only currently seeks the three categories that he does makes the Court’s task unusual. Ordinarily, it is clear to the Court that its rulings -will have some impact on the parties before it. That Pick-ard only currently seeks the three categories that he does also makes the Court’s task more difficult. While the Court has the benefit of the government’s Vaughn index, and a set of documents compiled by the government in response to Pickard’s broader initial FOIA request, the Court does not know which portions of which documents represent material that “Skinner has voluntarily disclosed to the public.” Accordingly, the Court cannot do a meaningful in camera review of the relevant materials.

Nevertheless, and in the absence of controlling authority in the Ninth Circuit, the Court concludes that the government may withhold Skinner’s name and the information that he voluntarily disclosed to the public under FOIA Exemption 7(D), which pertains to confidential informants. The Court does not reach the question of whether the same materials could also be withheld under Exemption 7(F), which pertains to safety, or Exemption 7(C), which pertains to privacy interests. The Court further holds that the government may withhold Skinner’s NADDIS number under Exemption 7(E), which pertains tó law enforcement techniques.

I. BACKGROUND

Plaintiff is an inmate at the U.S. Penitentiary in Tucson, Arizona, having been convicted in 2003 of offenses relating to LSD, and sentenced to life in prison. D MSJ (dkt. 184) at 1. In January 2005, Plaintiff submitted a request to the Drug Enforcement Administration (“DEA”) seeking information and documents pertaining to DEA informant Skinner. Id. at 2. Specifically, he.sought any information on

(1) Skinner’s criminal history (including records of arrests, convictions, warrants, or other pending cases), (2) records of all case names, numbers, and judicial districts where he testified under oath, (3) records of all monies paid in his capacity as a federal government informant, (4) all records of instances where the DEA intervened on his behalf to assist him in avoiding criminal prosecution, (5) all records of administrative sanctions imposed for dishonesty, false claims, or other deceit, (6) all records of any benefits of any nature conferred, (7) all records of deactivation as a confidential informant and the reasons for deactivation, and (8) all records concerning Skinner’s participation in criminal investigations.

Id. In February 2005, the DEA denied this request, citing FOIA Exemptions 6 and 7(C), without confirming or denying the existence of any records about Skinner. Id. The Office of Information and Privacy upheld that response. Id.

Plaintiff then brought suit in this court. Id. The government moved for summary judgment, and the Court denied the motion without prejudice, holding that the DEA had not adequately demonstrated that a Glomar response (a refusal to confirm or deny the existence of records pertaining to an individual) was appropriate. Order Denying MSJ (dkt. 62) at 5-6. The government then brought a second motion for summary judgment, fully briefing the Glomar response issue. See Pickard v. Dep’t of Justice, 653 F.3d 782, 784-85 (9th Cir. 2011). The Court granted that motion, finding that Skinner’s identity as a confidential informant had not been “officially confirmed” under the Privacy Act, and that a Glomar response was appropriate *1084under Exemptions 7(C) and 7(D). Id. at 785.

In July 2011, the Ninth Circuit reversed and remanded, holding that, because the government had publicly disclosed Skinner’s status as a confidential informant in open court in the course of official proceedings, a Glomar response was no longer appropriate. Id. at 787-88. The court explained, “[t]his is not to say that the DEA is now required to disclose any of the particular information requested by Pickard.” Id. at 788. The government was to produce a Vaughn index, “raise whatever other exemptions may be appropriate, and let the district court determine whether the contents, as distinguished from the existence, of the officially confirmed records may be protected from disclosure under the DEA’s claimed exemptions.” Id.

In March 2012, the government filed its third Motion for Summary Judgment but did not file a Vaughn index. See generally D 3rd MSJ (dkt. 140). Plaintiff filed a cross-motion for summary judgment. See generally P 3rd MSJ (dkt. 152). The Court denied both motions and ordered the government to file a Vaughn index within 5 days. See Minutes (dkt. 165). The government did so. See Vaughn Index (dkt. 166).

In May 2014, the Court denied the government’s fourth motion for summary judgment after finding its Vaughn index “supremely unhelpful.” MSJ Order (dkt. 198) at 1, 7, 11. The Court also denied Pickard’s cross-motion for summary judgment, which requested release of the same three categories of information at issue in the present motion. Id. at 11; P MSJ Reply (dkt. 191) at 3. The Court found that without an adequate Vaughn index, “the Court [could not] know if releasing something as basic as Skinner’s name would compromise an important privacy interest, endanger any individual’s (including Skinner’s) physical safety, or run afoul of one of the other claimed exemptions.” MSJ Order at 9. The Court then ordered the government “to submit (1) an adequate Vaughn index and (2) all of the responsive documents that the government continues to withhold in full or in part to Magistrate Judge Nathanael Cousins for review of ‘whether the contents, as distinguished from the existence, of the officially confirmed records may be protected from disclosure under the DEA’s claimed exemptions.’ ” Id. at 11 (citations omitted).

On December 24, 2015, Judge Cousins issued a tentative ruling, concluding that “the government has provided no evidence to carry its burden of proving that documents in the three categories qualify for exemptions,” and ordered the release of documents in the three categories. See Tentative Ruling (dkt. 227) at 1. The parties submitted additional briefing and an additional declaration, and on May 2, 2016, Judge Cousins issued an order releasing the three categories of documents. See generally Order to Release. The order explained that “the government may not offer only general government interests that are present in virtually all cases.” Id. at 2. It relied on United States v. Apperson, 642 Fed.Appx. 892 (10th Cir. 2016), which involved Pickard’s challenge to a Kansas district court’s denial of his motion to unseal Skinner’s confidential informant file. Id. at 2-3. Although Judge Cousins recognized that a motion to unseal a file “applies a different standard than a FOIA request,” he nonetheless found Apperson relevant because it, too, found the government’s articulated interests to be too generalized. Id. at 3.2 Judge Cousins also cited to a case *1085that this Court decided about Vaughn indexes, see Order at 2 (citing Muchnick v. Dep’t of Homeland Sec., No. CV 15-3060 CRB, 2016 WL 730291, at *3 (N.D. Cal. Feb. 24, 2016) (holding that boilerplate explanations for withholdings are improper)), although Judge Cousins had already found the Vaughn index in this case sufficient, see generally Order Finding Vaughn Index Sufficient (dkt. 219). The order did not discuss any documents or any claimed exemptions. See generally Order to Release. Judge Cousins ordered the parties to meet by May 16, 2016, to determine what information had been publicly disclosed, but the parties did not meet. Order to Release at 3; Response to Order Requesting Additional Information (dkt. 253) at 1 (explaining that because the government moved for De Novo determination, the parties have not conferred).3

The government filed a Motion for De Novo Determination of Dispositive Matter Referred to Magistrate Judge as to whether the government must release the withheld documents. See generally D Mot. De Novo (dkt. 244). Pickard opposed. P Opp’n to D Mot. De Novo (dkt. 246) at 1-2. However, the Court required the parties to re-file, as their briefs inappropriately incorporated previous briefs. See Order Terminating Motion, Vacating Hearing, Directing Filing of New Briefs, and Setting New Hearing Date (dkt. 255) at 2 (“Endless references to past briefs require the Court to scour the docket to determine what the parties are actually arguing.”). The government re-filed a Motion for De Novo Review of Judge Cousins’s order, 2d Mot. for De Novo Review, Pickard has opposed that motion, Opp’n to 2d Mot. for De Novo Review (dkt. 264), and the government has replied, Reply re 2d Mot. for De Novo Review (dkt. 265).

II. LEGAL STANDARD

“The Freedom of Information Act was enacted to facilitate public access to Government documents.” United States Dep’t of State v. Ray, 502 U.S. 164, 173, 112 S.Ct. 541, 116 L.Ed.2d 526 (1991). The purpose of the Act is “ ‘to pierce the veil of administrative secrecy and to open agency action to the light of public scrutiny.’ ” Id. (citing Dep’t of Air Force v. Rose, 425 U.S. 352, 361, 96 S.Ct. 1592, 48 L.Ed.2d 11 (1976)). “Consistently with this purpose, as well as the plain language of the Act, the strong presumption in favor of disclosure places the burden on the agency to justify the withholding of any requested documents.” Id.

“Pursuant to 28 U.S.C. § 636(b)(1), Federal Rule of Civil Procedure 72(b), and Civil Local Rule 72-3, a party may object to a magistrate judge’s proposed findings and recommendations by filing a motion for a de novo determination of a dispositive matterf ] referred to a magistrate judge.” REO Capital Fund 4, LLC v. Fuller, No. 15-cv-03252-JST, 2015 WL 4941742, at *1 *1086(N.D. Cal. Aug. 19, 2015). The motion “must be filed within fourteen days of the magistrate’s recommendation and must specifically identify the portions of the findings and recommendations to which the party objects, and the reasons for the objection(s).” Id. Upon the filing of such a motion, the court “shall make a de novo determination of those portions of the report or specified proposed findings or recommendations to which objection is made. A judge of the court may accept, reject, or modify, in whole or in part, the findings or recommendations made by the magistrate judge.” See 28 U.S.C.A. § 636(b)(1). While Judge Cousins issued an order rather than a recommendation, the order references Fed. R. Civ. P. 72(b) regarding dispositive matters. See Order to Release at 4.

III. DISCUSSION

The government argues that Judge Cousins erred in ordering the release of the three categories of material sought, because (A) official confirmation does not require any records to be released; (B) the threshold requirement of Exemption 7 has been met; (C) Exemption 7(D) applies to Skinner’s name and the materials he disclosed; (D) Exemptions 7(F) and 7(C) apply to Skinner’s name and the materials he disclosed; and (E) Exemption 7(E) applies to Skinner’s NADDIS number. See generally 2d Mot. for De Novo Review. This order concludes that withholding is proper under Exemptions 7(D) and 7(E).

A. Official Acknowledgment4

The government argues that official acknowledgment does not require the release of any of the materials in this case for two reasons: first, because “the Ninth Circuit already rejected [that argument] in this very case,” and second, because Pickard has not made the showing required. 2d Mot. for De Novo Review at 6-7. Pickard responds that the Ninth Circuit did not mean what it said about official confirmation, and that it is the government’s fault that he is unable to make the required showing. Opp’n to 2d Mot. for De Novo Review at 13-15.

1. Holding in Pickard re Official Acknowledgment

As to the Ninth Circuit’s holding in this case, the court explained: “[W]hen information has been either ‘officially acknowledged’ or ‘officially confirmed,’ an agency is not precluded from withholding information pursuant to an otherwise valid exemption claim; however, a Glomar response is no longer appropriate-” Pickard, 653 F.3d at 786 (emphasis added). The Ninth Circuit went on to cite to Wolf v. CIA, 473 F.3d 370, 379 (D.C. Cir. 2007), for the proposition that official acknowledgment related only to the existence or nonexistence of records, and that the government was to either disclose any officially acknowledged records or establish that the contents are exempt and that exemption had not been waived. Id. It also cited Benavides v. DEA, 968 F.2d 1243, 1248 (D.C. Cir. 1992), for the proposition that “Congress intended to permit the DEA to withhold documents under 7(C) and 7(D), even if the agency must, under subsection (c)(2) acknowledge their existence.” Id. Both Wolf and Benavides therefore recognize that official confirmation does not necessarily negate the application of other exemptions.

Pickard argues that the sentence the government relies on from Pickard “is dicta” and “likely the product of a drafting error.” Opp’n to 2d at 14. The sentence is not dicta—it was central to the court’s ruling both that a Glomar response was *1087inappropriate once the government officially confirmed Skinner’s status as a confidential informant, and that the parties were required to return to this Court and litigate the validity of any claimed exemptions. Nor is there any plausible drafting error. The cited portion of Wolf does not “state[] precisely the opposite” of what the court ordered here. See id. Rather, Wolf envisions that officially acknowledged records might still be subject to valid exemptions. See Wolf, 473 F.3d at 379. That is what the Pickard court held as well. See Pickard, 653 F.3d at 786. Further undercutting the idea of a “drafting error,” the court in Pickard repeated the same point a couple of pages later, explaining that while a Glomar response was “no longer available,” “[t]his is not to say that the DEA is now required to disclose any of the particular information requested by Pickard.” Pickard, 653 F.3d at 788. It explained that, having officially confirmed Skinner as an informant, the government was to produce a Vaughn index, “raise whatever other exemptions may be appropriate, and let the district court determine whether the contents, as distinguished from the existence, of the officially confirmed records may be protected from disclosure under the DEA’s claimed exemptions.” Id. (citing Wolf and Benavides). The government is therefore correct that the ruling in this case defeats the argument that official confirmation of Skinner as a confidential informant merits the disclosure of all of the information Pickard seeks. If the Ninth Circuit had believed that official confirmation worked as Pickard suggests, it could easily have said so.

2. Requirements for Official Acknowledgment

As to the required showing for official acknowledgment, the court in Pickard explained:

A fact is deemed “officially acknowledged” only if it meets three criteria: First, the information requested must be as specific as the information previously released. Second, the information requested must match the information previously disclosed; we noted, for example, that official disclosure did not waive the protection to be accorded information that pertained to a later time period. Third, we held that the information requested must already have been made public through an official and documented disclosure.

Pickard, 653 F.3d at 786 (citing Fitzgibbon v. CIA, 911 F.2d 755, 765 (D.C. Cir. 1990)). It is the plaintiffs burden to point to specific information in the public domain that appears to duplicate that being withheld. See Davis v. Dep’t of Justice, 968 F.2d 1276, 1279 (D.C. Cir. 1992) (explaining that the ultimate burden of persuasion rests with the government but that a party who asserts a claim of prior disclosure must bear the initial burden or pointing to specific information). “This is so because the task of proving the negative—that information has not been revealed—might require the government to undertake an exhaustive, potentially limitless search.” Id. at 1279.

There is no question that Pickard has successfully pointed to Skinner’s name, which the government officially acknowledged. See Pickard, 653 F.3d at 784 (“the government officially confirmed Skinner’s status as an informant in open court in the course of official proceedings”). But the Court does not imagine that what Pickard seeks are entire documents with everything redacted but Skinner’s name. Moreover, as discussed below, Exemption 7(D) presents a formidable hurdle to disclosing even Skinner’s name.

In his effort to obtain information Skinner has already disclosed and Skinner’s NADDIS number, Pickard has failed entirely to point to specific information that *1088the government is withholding and that matches information previously disclosed. See Pickard, 653 F.3d at 786. The government asserts: “he simply points to literally thousands of pages of Skinner’s transcripts and court filings and asks this Court to order information released if it matches based on the government’s review.” 2d Mot. for De Novo Review at 7 (noting that there are ten volumes of testimony from Pickard’s criminal trial, another transcript from the District of Kansas case, and 41 exhibits from a Northern District of Oklahoma case). Pickard disputes this, saying that he “has repeatedly directed the government’s attention to (1) the five days of public testimony Skinner provided ... and (2) the numerous documents from Skinner’s informant file (provided to him by the government) that Skinner has published in public court filings,” see Opp’n to 2d Mot. for De Novo Review, but he has neither directed the Court to such materials, nor specified which materials overlap.5 Pickard actually agrees that he “is unable to tie specific portions of Skinner’s public testimony to specific withheld documents,” but he argues that this “is not a fault owing to Mr. Pickard. Rather, the govern-merit’s refusal to provide specific descriptions of the withheld records renders such a task impossible.” Id. at 14-15. This argument, which Pickard repeated at the motion hearing, fails because the Court has found the Vaughn index in this case acceptable. See generally Order Finding Vaughn Index Sufficient; Order Denying Mot. (dkt. 222). It is also curious that Pickard cannot make such a showing if in fact he already has access to an unredact-ed copy of Skinner’s file from the District of Kansas/Tenth Circuit litigation. See Apperson, 642 Fed.Appx. at 893.

Because Pickard has failed to make an adequate showing of official acknowledgment, the Court will proceed to analyzing the claimed exemptions.6

B. Threshold Requirement

All of the government’s claimed exemptions in this case arise under Exemption 7, which pertains to documents “compiled for law enforcement purposes.” See generally 2d Mot. for De Novo Review (claiming application of Exemptions 7(D), 7(F), 7(C), and 7(E)); FBI v. Abramson, 456 U.S. 615, 622, 102 S.Ct. 2054, 72 L.Ed.2d 376 (1982). *1089This Court has abeady held that the documents were all compiled for law enforcement purposes. See Order Granting Defendant’s Motion for Summary Judgment at 6 (“In view of the nature of plaintiffs FOIA request and the descriptions of the systems of records where responsive records likely would be located, the court is satisfied that any responsive records would be law enforcement records covered by FOIA Exemption 7.”). The evidence continues to support that conclusion. See Tenth Supp. Little Decl. (dkt. 288-1) ¶ 7 (“The records requested by plaintiff were law enforcement records gathered in accordance with DEA’s responsibilities under the Comprehensive Drug Abuse Prevention and Control Act of 1970.”).

Pickard acknowledges that the government has satisfied the Exemption 7 threshold requbement for all the documents but one: “a letter written by the DEA to the CHP that describes one instance of the DEA intervening on Skinner’s behalf to avoid criminal charges.” Opp’n to 2d Mot. for De Novo Review at 15. Pickard argues that because the government represents that “it is not the practice of DEA to intervene on behalf of any individual to assist them in avoiding criminal prosecution,” then “the letter falls outside DEA’s practices and law enforcement mandate.” Id. (citing Pratt v. Webster, 673 F.2d 408, 420-21 (D.C. Cb. 1982); Taylor v. DOJ, 257 F.Supp.2d 101, 108 (D.D.C. 2003)).

This argument is unpersuasive for two reasons. Fbst, having reviewed the document, the Court observes that it was plausibly compiled for law enforcement purposes. Second, as Pickard is only currently seeking materials that Skinner disclosed, and the only disclosure of this information appears to have come from Skinner’s wife, see Rumold Deck Ex. E at 63, the document is not subject to disclosure in this motion. Accordingly, the government has met the threshold requbement of Exemption 7—that the relevant documents be compiled for law enforcement purposes— and so the Court will turn to the individual claimed exemptions.

C. Exemption 7(D)

The fbst individual exemption the government asserts is Exemption 7(D). Exemption 7(D) allows the government to withhold law enforcement records or information if it “could reasonably be expected to disclose the identity of a confidential source... and, in the case of a record or information compiled by criminal law enforcement authority in the course of a criminal investigation,.. .information furnished by a confidential source.” 5 U.S.C. § 552(b)(7)(D). The government argues here that “[u]nder the plain language of the statute, Skinner’s name is properly withheld because it would literally disclose the identity of a confidential source, and information Skinner provided is properly withheld, even if he later testified about it, because it would literally disclose information furnished by a confidential source.” 2d Mot. for De Novo Review at 8. The government asserts: “Exemption 7(D) cannot be waived.” Id. Pickard disagrees, arguing that because the government officially confirmed Skinner as a DEA informant, because Skinner testified, and because the government provided documents to Skinner, “continued withholding ... under Exemption 7(D) is improper.” Opp’n to 2d Mot. for De Novo Review at 16. The Court agrees with the government.

1. Ninth Circuit Authority on Exemption 7(D)

Unfortunately, there is no particularly relevant precedent from the Ninth Cbcuit on Exemption 7(D).

Pickard asserts that “In this cbcuit, an informant’s public testimony waives Exemption 7(D)’s protection for all information provided by the informant—even if that information was not disclosed at tri*1090al.” See Opp’n to 2d Mot. for De Novo Review at 16 (citing Van Bourg, Allen, Weinberg & Roger v. NLRB, 751 F.2d 982, 986 (9th Cir. 1986)). That assertion misrepresents Van Bourg, however, which involved a labor investigation, not a criminal investigation, and which turned on whether the informant was truly a confidential source. See 751 F.2d at 986 (“for exemption 7(D) to be applicable, there must be a finding that the source of the affidavit was explicitly or implicitly guaranteed confidentiality.”). Van Bourg provides no support for Pickard’s argument at the motion hearing that once an informant testifies, he loses his expectation of confidentiality; instead Van Bourg focuses on the informant’s understanding at the time that he provided information to the government. The Ninth Circuit noted that individuals who submit affidavits to the NLRB “have no reasonable expectation of confidentiality and should expect their names and testimony to be revealed if the investigation results in a formal healing.” Id. In other words, there was no confidential source in Van Bourg to begin with.7 That is an altogether different scenario than this case, in which there is no question that Skinner was a confidential informant in a criminal investigation. See Pickard, 653 F.3d at 788 (referencing “Skinner’s status as a confidential informant in Pickard’s case”).8

The government claims that Prudential Locations LLC v. Dept. of Housing & Urban Development, 739 F.3d 424 (9th Cir. 2013), serves as precedent, but that case was primarily about Exemption 6. The Ninth Circuit in Prudential Locations explained that, under Exemption 7(D), “[i]f the individual is a ‘confidential source,’ that is the end of the matter; there is no need to balance the individual’s privacy interest against the public interest in disclosure, as is required under Exemption 6.” 739 F.3d at 434. The government clings to the “end of the matter” language, and also relies on the language from Church of Scientology of Cal. v. Dep’t of Justice, 612 F.2d 417, 426-27 (9th Cir. 1979), stating that Exemption 7(D) must be interpreted according to its “plain meaning.” See 2d Mot. for De Novo Review at 8. While both cases mildly support the government’s position, neither involves a confidential informant who has testified in criminal proceedings and disclosed some information.

2. Out-of-Circuit Authority on Exemption 7(D)

More helpful is authority from other circuits.

The landmark case about Exemption 7(D) is the en banc decision in Irons v. FBI, 880 F.2d 1446 (1st Cir. 1989), which both the government and Pickard rely on in support of their positions. See 2d Mot. for De Novo Review at 8, 10-11; Opp’n to 2d Mot. for De Novo Review at 16-17, 19. Importantly, the court in Irons explicitly did not rule on whether public testimony *1091could waive Exemption 7(D) protection for information publicly disclosed at trial. See Irons, 880 F.2d at 1448.9 The court’s holding, which Pickard’s counsel read aloud at the motion hearing, was “that public testimony by ‘confidential sources’ cannot ‘waive’ the FBI’s right under the second clause of exemption 7(D) to withhold ‘information furnished by a confidential source’ and not actually revealed in public.” Id. at 1456-57 (emphasis added). The court noted, however, that some courts have held that even information disclosed at trial is protected under Exemption 7(D). See id. at 1448 (citing L & C Marine Transport, Ltd. v. United States, 740 F.2d 919, 925 (11th Cir. 1984); Lame v. Dep’t of Justice, 654 F.2d 917, 925 n.8 (3d Cir. 1981); Lesar v. Dep’t of Justice, 636 F.2d 472, 491 (D.C. Cir. 1980)).

Even though Irons did not reach the issue of materials publicly disclosed by an informant, it unambiguously held that Exemption 7(D) cannot be waived, and it provided extensive support for that conclusion. See Irons, 880 F.2d at 1448-49. First, the court noted that neither the plain language of Exemption 7(D) “nor any other relevant language, says anything at all about ‘waiver.’ Other courts (indeed virtually all other courts) have interpreted the statute’s language literally in this respect.” Id. at 1449. The court cited approvingly to Lame, 654 F.2d at 925, which held that “all the information given by a confidential source is exempt,” and that “the subsequent disclosure of information originally given in confidence does not render non-confidential any of the information originally provided.” Id. Second, the court examined the legislative history, concluding that Congress intended “a literal interpretation,” as it intended the exemption “to help law enforcement agencies to recruit, and to maintain, confidential sources; its object was not simply to protect the source, but also to protect the flow of information to the law. enforcement agency.” Id.10Third, the court observed that circuits have “specifically interpreted the ‘information furnished’ exemption to apply irrespective of subsequent public identification of the source” and “irrespective of the nature of the information (so long as the information meets the criteria in the exemption).” Id. at 1452. Fourth, the. court explained that, “while courts in some exemption 7(D) cases have used the word ‘waiver,’ ... they have not used that word in any context or in any way that argues for application of a ‘waiver doctrine’ in the type of case before us.” Id.11 Fifth, the *1092court held that creating a waiver exception would “run[ ] afoul of the statute’s intent to provide ‘workable’ rules.” Id. at 1455-56 (internal quotation marks omitted).

Irons did not, as Pickard claims, “[find] that Exemption 7(D) did not apply to (1) the identity of an informant ...; and (2) information that was actually disclosed by the informant in public testimony.” See Opp’n to Mot. for De Novo Review at 17; Moffat v. Dep’t of Justice, 716 F.3d 244, 253 (1st Cir. 2013) (observing that Irons “reserved the question of whether 7(D) continues to apply to the specific information that has already been publically disclosed”). Moreover, given its logic and reasoning, the most plausible reading of Irons is that Exemption 7(D) applies to such information. See Irons, 880 F.2d at 1456 (“exemption 7(D) contains language that, without qualification, exempts from disclosure ‘information furnished by a confidential source.’ ”).

Other courts to actually address the issue of information derived from a confidential source and subsequently publicly disclosed have held that Exemption 7(D) applied.12 In Ferguson v. FBI, 957 F.2d 1059, 1068 (2d Cir. 1992), the Second Circuit endorsed the reasoning in Irons and “reject[ed] the idea that subsequent disclosures of the identity of the confidential source or of some of the information provided by a confidential source requires full disclosure of information provided by such a source.” The court explained that “Exemption 7(D) is concerned not with the content of the information, but only with the circumstances in which the information was obtained.” Id. at 1069. In Parker v. Dep’t of Justice, 934 F.2d 375, 380 (D.C. Cir. 1991), the D.C. Circuit held that “once an agency establishes that it received the requested information in confidence, ‘the source will be deemed a confidential one, and both the identity of the source and the information he or she provided will be immune from FOIA disclosure.’ ” In Lame, 654 F.2d at 925, one of the cases discussed in Irons, the Third Circuit explained that “once there has been an expressed or implied assurance of confidentiality, a subsequent release or publication by the government of a portion of the information does not negate the exemption for any of the information originally given.” 13 In Neely v. FBI, 208 F.3d 461, 466 *1093(4th Cir. 2000), the Fourth Circuit relied on the Supreme Court’s explanation of “confidential source” in Department of Justice v. Landano, 508 U.S. 165, 113 S.Ct. 2014, 124 L.Ed.2d 84 (1993), concluding that “in Landano, the Supreme Court defined ‘confidential source’ in terms of the ‘understanding’ reached between the informant and the FBI at the time the information was communicated to the FBI, not in terms of whether the information subsequently remained non-public.” The Fourth Circuit held that “a source could remain a ‘confidential source’ for purposes of Exemption 7(D), even if the source’s communication with the FBI is subsequently disclosed at trial or pursuant to the government’s Brady obligations.” Id. (citing Landano, 508 U.S. at 173-74, 113 S.Ct. 2014). See also Kimberlin v. Dep’t of Treasury, 774 F.2d 204, 209 (7th Cir. 1985) (“The disclosure of information given in confidence does not render non-confidential any of the information originally provided.”); Kiraly v. FBI, 728 F.2d 273, 278 (6th Cir. 1984) (discussing legislative intent behind Exemption 7(D) and concluding that it “protects without exception and without limitation the identity of informers,” even where individual’s identity as FBI informant was already known).

Pickard tries to steer the Court away from the weight of the authority on this issue with two arguments: one involves trying to distinguish that authority, and the other involves the D.C. Circuit, which has held that official acknowledgment can waive Exemption 7(D).

Pickard first tries to distinguish Ferguson, 957 F.2d 1059, Kiraly, 728 F.2d 273, and Parker, 934 F.2d 375, just three of the cases upon which the government relies. See Opp’n to 2d Mot. for De Novo Review at 18-19. Pickard asserts that in these cases, state governments were eliciting testimony about a federal confidential informant, and that “no informant was ever confirmed by the federal government.” Id. However, courts do not seem to focus on the state/federal dynamic, or on whether it was the informants or the government that revealed the informants’ status. In fact, the Ferguson court explained that “[t]he statutory language does not leave room for a judicial balancing of the equities, or for a determination of whether any harm would result from disallowing an exemption.” Ferguson, 957 F.2d at 1069. By that reasoning, Exemption 7(D) would still cover information disclosed publicly even if doing so seemed meaningless. Further, the Irons court noted that “[t]he words ‘furnished by a confidential source’ do not mean that the information or identity of the source is secret; they simply mean that the information was ‘provided in confidence’ at the time it was communicated to the [DEA].” See Irons, 880 F.2d at 1448. Accordingly, Pickard’s attempt to distinguish some of the relevant authority is unpersuasive.

More significant is Davis, 968 F.2d 1276, which Pickard just briefly mentions. Davis chiefly concerned the burden of proof when the government asserted a number of exemptions, including Exemption 7(D), and the plaintiff claimed that the tapes at issue had already been publicly disclosed at trial. 968 F.2d at 1279. The court noted that the government was willing to give the plaintiff “only exactly what he can find in hard copy,” requiring “the requester to point to ‘specific’ information identical to that being withheld.” Id. at 1280. “It does *1094not suffice to show ... that some of the tapes were played to shift the burden to the government”—the plaintiff had to “point to specific information in the public domain.” Id. The court in Davis agreed that because the informant was a confidential source, “the application of Exemption 7(D) is automatic.” Id. at 1281. It observed that “[e]ven when the source testifies in open court.. .he does not thereby ‘waive the [government’s] right to invoke Exemption 7(D) to withhold.. .information furnished by a confidential source not actually revealed in public.” Id. (citing Parker, 934 F.2d at 379-80). It went on to hold, however, that “[t]he government is obliged to disclose only the ‘exact information’ to which the source actually testified.” Id. (citing Dow Jones & Co. v. Dep’t of Justice, 917 F.2d 571, 577 (D.C. Cir. 1990)).

The court in Dow Jones & Co., had held that in extraordinary circumstances, “if the exact information given to the FBI has already become public, and the fact that the informant gave the same information to the FBI is also public, there would be no grounds to withhold.” 917 F.2d at 577. However, “[t]he requester will rarely, if ever, have absolutely solid evidence showing that the source of an FBI interview in a law enforcement investigation has manifested complete disregard for confidentiality.” See id. at 577, n.5 (“One can imagine, for instance, a source falsely describing publicly what he or she told the FBI privately.”).14 And indeed, in Davis, the court explained that “[w]hat that means for this case, essentially, is that the government is entitled to withhold the tapes obtained through the informant’s assistance unless it is specifically shown that those tapes, or portions of them, were played during the informant’s testimony.” 968 F.2d at 1281.

Davis therefore shows the D.C. Circuit recognizing the application of the official acknowledgment doctrine to Exemption 7(D). See also Cobar v. Dep’t of Justice, 81 F.Supp.3d 64, 72 (D.D.C. 2015) (relying on Parker and Irons, holding in Exemption 7(D) context that “for information or a record to lose its protected status based on public disclosure, the information must truly be in the public domain and there must be an exact identity between the publicly disclosed information or document and the information or documents sought under the FOIA.”).15 Other circuits have not so held. See, e.g., Lame, 654 F.2d at 925 (citation omitted) (“once there has been an expressed or implied assurance of confidentiality, a subsequent release or publication by the government of a portion of information does not negate the exemption for any of the information originally given.”). And the Ninth Circuit has not reached the issue.

Because this Court finds persuasive the numerous courts to focus on whether information was originally given in confidence, regardless of whether or not that information later becomes public, this Court holds that Exemption 7(D) justifies the withholding of Skinner’s name and the information he has publicly disclosed.16 *1095The Court notes that because it does not know which portions of which of the documents in the in camera materials are “information Skinner has publicly disclosed,” the Court cannot independently verify whether all such information is covered by Exemption 7(D), However, the government represented to the Court at the motion hearing that all of the “information Skinner has publicly disclosed” is covered by Exemption 7(D), the Court’s in camera review of the broader set of responsive materials gives it no reason to doubt this characterization, and—though he contends that the government/Skinner has waived Exemption 7(D)—Pickard has not disputed that the relevant materials “could reasonably be expected to disclose the identity of a confidential source” or constitute “information furnished by a confidential source.” See 5 U.S.C. § 552(b)(7)(D).

D. Exemptions 7(F) and 7(C)

The next individual exemptions the government asserts for Skinner’s name and the information he has publicly disclosed are Exemptions 7(F) and 7(C). Exemption 7(F) allows the government to, withhold law.enforcement records or information if they “could reasonably be expected to endanger the life or physical safety of any individual.” See 5 U.S.C. § 552(b)(7)(F). Exemption 7(C) allows the government to withhold law enforcement records or information if they “could reasonably be expected to constitute an unwarranted invasion of personal privacy.” See 5 U.S.C. § 552(b)(7)(C). Both of these exemptions require the Court to do a document-by-document review—in the case of 7(F), to determine whether material in one document might endanger Skinner’s life but material in another might not, and in the case of 7(C), to balance the relevant privacy and public interests implicated by material in each document. See Van Bourg v. NLRB, 656 F.2d 1356, 1358 (9th Cir. 1981) (courts are to “state in reasonable detail the reasons for its decision as to each document in dispute”).

Because the Court does not know which portions of which of the documents in the in camera materials are “information Skinner has publicly disclosed,” the Court cannot conduct such a review. The Court is also concerned that Pickard’s request, which would require the government to compile a subset of the in camera documents in a form that is presently unavailable to the general public, is problematic under Department of Justice v. Reporters Committee For Freedom of the Press, 489 U.S. 749, 109 S.Ct. 1468, 103 L.Ed.2d 774 (1989).17 Accordingly, rather than opine on matters in the abstract, the Court does not reach the parties’ arguments as to Exemptions 7(F) or 7(C).

E. Exemption 7(E)

Finally, the government asserts Exemption 7(E) as the basis for its withholding of Skinner’s NADDIS number. 2d Mot. for De Novo Review at 18-20. Exemption 7(E) allows the government to withhold law enforcement records or infor*1096mation if they “would disclose techniques and procedures for law enforcement investigations or prosecutions, or would disclose guidelines for law enforcement investigations or prosecutions if such disclosure could reasonably be expected to risk circumvention of the law.” 5 U.S.C. § 552(b)(7)(E). The Ninth Circuit recently clarified that the restrictive language, “if such disclosure could reasonably be expected to risk circumvention of the law,” only applies to the second clause, which means that the first clause, “would disclose techniques and procedures for law enforcement investigations or prosecutions,” is sufficient for withholding. See Hamdan v. Dep’t of Justice, 797 F.3d 759, 778 (9th Cir. 2015). In other words, the first clause “provides categorical protection for techniques and procedures used in law enforcement investigations or prosecutions” and “requires no demonstration of harm or balancing of interests.” See Keys v. Dep’t of Homeland Sec., 510 F.Supp.2d 121, 129 (D.D.C. 2007) (internal quotation marks, citations and brackets omitted). However, “7(E) only exempts investigative techniques not generally known to the public.” See Rosenfeld v. Dep’t of Justice, 57 F.3d 803, 815 (9th Cir. 1995) (affirming the district court’s decision that a pretext phone call is a well-known investigative technique, and thus not protected by exemption 7(E)).

The government argues that disclosing Skinner’s NADDIS number would disclose a law enforcement technique, and that the use of NADDIS numbers is not generally known to the public. 2d Mot. for De Novo Review at 19. In support of those assertions, the government relies primarily on their agent’s declaration. Id. The declaration states that NADDIS numbers are a part of the DEA’s procedure; they are “part of the DEA’s system of identifying information and individuals” and are used “within the DEA investigative records system as directed by the DEA Agents Manual.” Tenth Supp. Little Decl. ¶ 17. NADDIS numbers are “assigned to drug violators and suspected drug violators known to DEA and entities that are of investigative interest. Each number is unique and is assigned only to one violator within DEA NADDIS indices.” Id. ¶ 19. They “are assigned by DEA for internal use only” and “relate solely to internal DEA investigative practices and guidelines.” Id ¶ 17. “The precise manner in which NADDIS functions and the manner in which NADDIS numbers are assigned and utilized by DEA is not commonly known to the general public.” Id. ¶ 21.

At the motion hearing, the Court challenged the notion that disclosing a single NADDIS number really “would disclose techniques and procedures.” See 5 U.S.C. § 552(b)(7)(E). Pickard had argued in his briefing that he does not “seek information about how the government uses the NAD-DIS system... only ... the release of a single number.” Opp’n to 2d Mot. for De Novo Review at 25. At first blush, it appeared that the government had disclosed more information about the NADDIS procedures in its declaration in this case than would be disclosed if the government were to simply release Skinner’s NADDIS number to Pickard. But the government argued persuasively that the DEA uses a particular method to assign NADDIS numbers, and that the more NADDIS numbers get out, the more people will be able to discern that methodology. Documents released pursuant to FOIA are released to all of the world; the Court must therefore consider the release of Skinner’s NADDIS number not only to Pickard but to “the general public.” See Lahr v. NTSB, 569 F.3d 964, 977 n.12 (9th Cir. 2009). If Skinner’s number is released, and other numbers are released, then the public might be able to deduce, for example, that the DEA assigns individuals NADDIS numbers starting with 1 if those individu*1097als are cooperating with the government, or live in a particular state, or have a criminal history, or have a particular racial makeup, or any number of other characteristics.

Pickard argues that a NADDIS number is a technique generally known to the public. See Response to Tentative at 8 (dkt. 237).18 He cites to a few instances in which NADDIS numbers have surfaced, although that evidence does not support his position. See Opp’n to 2d Mot. for De Novo Review at 25. In Zavala v. DEA, 667 F.Supp.2d 85, 97 (D.D.C. 2009), the court did refer to an individual’s NADDIS number—by number—but held that NADDIS numbers properly and “routinely are withheld” under Exemption 2. Rumold Deck Ex. J, which pertained to the purported NADDIS number of an individual named Owsley Stanley involves a deceased individual; moreover, the government objects to this evidence as unauthenticated, see 2d Mot. for De Novo Review at 20, re doc. # 173-1, Ex 1, Ex. A. And in Marino v. DEA, 15 F.Supp.3d 141, 146 (D.D.C. 2014), while the court observed that “Marino suspected that 3049901 was the NADDIS number assigned to Lopez, and therefore, his request effectively sought the DEA’s investigative file on Lopez,” the court did not disclose (or confirm) the NADDIS number and merely held that the government could not use a Glomar response. None of Pick-ard’s cases involve courts granting FOIA requests to disclose NADDIS numbers.

On the other hand, there is precedent for withholding NADDIS numbers under Exemption 7(E). In Miller v. Dep’t of Justice, 872 F.Supp.2d 12, 29 (D.D.C. 2012), the court stated that “[b]ecause the NAD-DIS numbers were created for a law enforcement purpose and their disclosure may disclose techniques and procedures for law enforcement investigation, this Court finds that they are properly withheld under Exemption 7(E).” The court also observed that NADDIS numbers “reflect procedures prescribed by the DEA Agents Manual, which according to defendant, identify law enforcement techniques.” Id. at 28-29 (internal quotation marks omitted). Other courts have also so held. See, e.g., Dorsey v. Executive Office for U.S. Attorneys, 83 F.Supp.3d 347, 357 (D.D.C. 2015); Ortiz v. Dep’t of Justice, 67 F.Supp.3d 109, 123 (D.D.C. 2014); Higgins v. Dep’t of Justice, 919 F.Supp.2d 131, 150-51 (D.D.C. 2013).19 And the Ninth Circuit appears to have adopted its reasoning on this exemption from the D.C. district courts. See Rosenfeld, 57 F.3d at 815 (citing D.C. district court opinions, stating, “[w]e agree with these courts’ reasoning, and adopt it as the law of this Circuit.”).

Because the Court concludes that disclosing Skinner’s NADDIS number would *1098reveal techniques and procedures that are not generally known to the public, the Court holds that withholding is proper under Exemption 7(E).

IV. CONCLUSION

For the foregoing reasons, the Court GRANTS the motion for de novo review, and HOLDS that the government may withhold (1) Skinner’s name and information Skinner has publicly released under Exemption 7(D), and (2) Skinner’s NAD-DIS number under Exemption 7(E).

IT IS SO ORDERED.